Oracle® Fusion Middleware

Developing Oracle WebLogic Tuxedo Connector Applications for Oracle WebLogic Server

12c (12.2.1.2.0)

E78037-02

December 2016

This document introduces the Oracle WebLogic Tuxedo Connector application development environment. It describes how to develop EJBs that allow Oracle WebLogic Server to interoperate with Oracle Tuxedo objects.

Oracle Fusion Middleware Developing Oracle WebLogic Tuxedo Connector Applications for Oracle WebLogic Server, 12c (12.2.1.2.0)

E78037-02

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Contents

Preface

- Documentation Accessibility

- Conventions

1 Introduction to Oracle WebLogic Tuxedo Connector Programming

- 1.1 Guide to this Document

- 1.2 Developing Oracle WebLogic Tuxedo Connector Applications

- 1.2.1 Developing Oracle WebLogic Tuxedo Connector Clients

- 1.2.2 Developing Oracle WebLogic Tuxedo Connector Servers

- 1.2.3 Oracle WebLogic Tuxedo Connector Interoperability with Oracle Tuxedo CORBA objects

- 1.3 Oracle WebLogic Tuxedo Connector JATMI Primitives

- 1.4 Oracle WebLogic Tuxedo Connector TypedBuffers

- 1.5 New and Changed WTC Features for this Release

2 Developing Oracle WebLogic Tuxedo Connector Client EJBs

- 2.1 Joining and Leaving Applications

- 2.1.1 Joining an Application

- 2.1.2 Leaving an Application

- 2.2 Basic Client Operation

- 2.2.1 Get an Oracle Tuxedo Object

- 2.2.2 Perform Message Buffering

- 2.2.3 Send and Receive Messages

- 2.2.3.1 Request/Response Communication

- 2.2.3.1.1 Using Synchronous Service Calls

- 2.2.3.1.2 Using Deferred Synchronous Service Calls

- 2.2.3.1.3 Using Asynchronous Calls

- 2.2.3.2 Conversational Communication

- 2.2.3.3 Enqueuing and Dequeuing Messages

- 2.2.4 Close a Connection to an Oracle Tuxedo Object

- 2.3 Example Client EJB

3 Developing Oracle WebLogic Tuxedo Connector Service EJBs

- 3.1 Basic Service EJB Operation

- 3.1.1 Access Service Information

- 3.1.2 Buffer Messages

- 3.1.3 Perform the Requested Service

- 3.1.3.1 Return Client Messages for Request/Response Communication

- 3.1.3.2 Use tpsend and tprecv for Conversational Communication

- 3.2 Example Service EJB

4 Using Oracle WebLogic Tuxedo Connector for RMI/IIOP and CORBA Interoperability

- 4.1 How to Develop Oracle WebLogic Tuxedo Connector Client Beans using the CORBA Java API

- 4.1.1 Using CosNaming Service

- 4.1.1.1 Example ToupperCorbaBean.java Code

- 4.1.2 Using FactoryFinder

- 4.1.2.1 WLEC to Oracle WebLogic Tuxedo Connector Migration

- 4.1.2.2 Example Code

- 4.2 How to Develop RMI/IIOP Applications for the Oracle WebLogic Tuxedo Connector

- 4.2.1 How to Modify Inbound RMI/IIOP Applications to use the Oracle WebLogic Tuxedo Connector

- 4.2.2 How to Develop Outbound RMI/IIOP Applications to use the Oracle WebLogic Tuxedo Connector

- 4.2.2.1 How to Modify the ejb-jar.xml File to Pass a FederationURL to EJBs

- 4.2.2.1.1 Assign env-entry-name

- 4.2.2.1.2 Assign env-entry-type

- 4.2.2.1.3 Assign env-entry-value

- 4.2.2.2 How to Modify EJBs to Use FederationURL to Access an Object

- 4.3 How to Use FederationURL Formats

- 4.3.1 Using corbaloc URL Format

- 4.3.1.1 Examples of corbaloc:tgiop

- 4.3.1.2 Examples using -ORBInitRef

- 4.3.1.3 Examples Using -ORBDefaultInitRef

- 4.3.2 Using the corbaname URL Format

- 4.3.2.1 Examples Using -ORBInitRef

- 4.4 How to Manage Transactions for Oracle Tuxedo CORBA Applications

5 Oracle WebLogic Tuxedo Connector JATMI Transactions

- 5.1 Global Transactions

- 5.2 JTA Transaction API

- 5.2.1 Types of JTA Interfaces

- 5.2.1.1 Transaction

- 5.2.1.2 TransactionManager

- 5.2.1.3 UserTransaction

- 5.2.2 JTA Transaction Primitives

- 5.3 Defining a Transaction

- 5.3.1 Starting a Transaction

- 5.3.1.1 Using TPNOTRAN

- 5.3.2 Terminating a Transaction

- 5.4 Oracle WebLogic Tuxedo Connector Transaction Rules

- 5.5 Example Transaction Code

6 Oracle WebLogic Tuxedo Connector JATMI Conversations

- 6.1 Overview of Oracle WebLogic Tuxedo Connector Conversational Communication

- 6.2 Oracle WebLogic Tuxedo Connector Conversation Characteristics

- 6.3 Oracle WebLogic Tuxedo Connector JATMI Conversation Primitives

- 6.4 Creating Oracle WebLogic Tuxedo Connector Conversational Clients and Servers

- 6.4.1 Creating Conversational Clients

- 6.4.1.1 Establishing a Connection to an Oracle Tuxedo Conversational Service

- 6.4.1.2 Example TuxedoConversationBean.java Code

- 6.4.2 Creating Oracle WebLogic Tuxedo Connector Conversational Servers

- 6.5 Sending and Receiving Messages

- 6.5.1 Sending Messages

- 6.5.2 Receiving Messages

- 6.6 Ending a Conversation

- 6.6.1 Oracle Tuxedo Application Originates Conversation

- 6.6.2 Oracle WebLogic Tuxedo Connector Application Originates Conversation

- 6.6.3 Ending Hierarchical Conversations

- 6.7 Executing a Disorderly Disconnect

- 6.8 Understanding Conversational Communication Events

- 6.9 Oracle WebLogic Tuxedo Connector Conversation Guidelines

7 Using FML with Oracle WebLogic Tuxedo Connector

- 7.1 Overview of FML

- 7.2 The Oracle WebLogic Tuxedo Connector FML API

- 7.3 FML Field Table Administration

- 7.3.1 Using the DynRdHdr Property for mkfldclass32 Class

- 7.4 Using TypedFML32 Constructors

- 7.4.1 Gaining TypedFML32 Performance Improvements

- 7.5 tBridge XML/FML32 Translation

- 7.5.1 FLAT

- 7.5.2 NO

- 7.5.3 FML32 Considerations

- 7.6 Using the XmlFmlCnv Class for XML to and From FML/FML32 Translation

- 7.6.1 Limitations of XmlFmlCnv Class

- 7.7 MBSTRING Usage

- 7.7.1 Sending MBSTRING Data to an Oracle Tuxedo Domain

- 7.7.2 Receiving MBSTRING Data from an Oracle Tuxedo Domain

- 7.7.3 Using FML with Oracle WebLogic Tuxedo Connector

8 Oracle WebLogic Tuxedo Connector JATMI VIEWs

- 8.1 Overview of Oracle WebLogic Tuxedo Connector VIEW Buffers

- 8.2 How to Create a VIEW Description File

- 8.2.1 Example VIEW Description File

- 8.3 How to Use the viewj Compiler

- 8.4 How to Pass Information to and from a VIEW Buffer

- 8.5 How to Use VIEW Buffers in JATMI Applications

- 8.5.1 How to Get VIEW32 Data In and Out of FML32 Buffers

- 8.6 Using the XmlViewCnv Class for XML to and From View/View(32) Translation

- 8.6.1 Translating Nested Views

9 How to Create a Custom AppKey Plug-in

- 9.1 How to Create a Custom Plug-In

- 9.2 Example Custom Plug-in

10 Application Error Management

- 10.1 Testing for Application Errors

- 10.1.1 Exception Classes

- 10.1.2 Fatal Transaction Errors

- 10.2 Oracle WebLogic Tuxedo Connector Time-Out Conditions

- 10.2.1 Blocking vs. Transaction Time-out

- 10.2.2 Effect on commit()

- 10.2.3 Effect of TPNOTRAN

- 10.3 Guidelines for Tracking Application Events

Preface

This preface describes the document accessibility features and conventions used in this guide—.

Documentation Accessibility

For information about Oracle's commitment to accessibility, visit the Oracle Accessibility Program website at http://www.oracle.com/pls/topic/lookup?ctx=acc&id=docacc.

Access to Oracle Support

Oracle customers that have purchased support have access to electronic support through My Oracle Support. For information, visit http://www.oracle.com/pls/topic/lookup?ctx=acc&id=info or visit http://www.oracle.com/pls/topic/lookup?ctx=acc&id=trs if you are hearing impaired.

Conventions

The following text conventions are used in this document:

Convention

Meaning

boldface

Boldface type indicates graphical user interface elements associated with an action, or terms defined in text or the glossary.

italic

Italic type indicates book titles, emphasis, or placeholder variables for which you supply particular values.

monospace

Monospace type indicates commands within a paragraph, URLs, code in examples, text that appears on the screen, or text that you enter.

1 Introduction to Oracle WebLogic Tuxedo Connector Programming

This chapter provides information about the development environment you will be using to write code for applications that interoperate between Oracle WebLogic Server and Oracle Tuxedo.

This chapter includes the following sections:

- Guide to this Document

- Developing Oracle WebLogic Tuxedo Connector Applications

- Oracle WebLogic Tuxedo Connector JATMI Primitives

- Oracle WebLogic Tuxedo Connector TypedBuffers

- New and Changed WTC Features for this Release.

Note:

For information on how to develop Oracle WebLogic Server Enterprise JavaBeans (EJBs), see Developing Enterprise JavaBeans, Version 2.1, for Oracle WebLogic Server.

1.1 Guide to this Document

This document introduces the Oracle WebLogic Tuxedo Connector application development environment. It describes how to develop EJBs that allow Oracle WebLogic Server to interoperate with Oracle Tuxedo objects.

The document is organized as follows:

- Introduction to Oracle WebLogic Tuxedo Connector Programming, provides information about the development environment you will be using to write code for applications that interoperate between Oracle WebLogic Server and Oracle Tuxedo.

- Developing Oracle WebLogic Tuxedo Connector Client EJBs, provides information on how to create client EJBs.

- Developing Oracle WebLogic Tuxedo Connector Service EJBs, provides information on how to create service EJBs.

- Using Oracle WebLogic Tuxedo Connector for RMI/IIOP and CORBA Interoperability, provides information on how to develop CORBA applications for the Oracle WebLogic Tuxedo Connector.

- Oracle WebLogic Tuxedo Connector JATMI Transactions, provides information on global transactions and how to define and manage them in your applications.

- Oracle WebLogic Tuxedo Connector JATMI Conversations, provides information on conversations and how to define and manage them in your applications.

- Using FML with Oracle WebLogic Tuxedo Connector, discusses the Field Manipulation Language (FML) and describes how the Oracle WebLogic Tuxedo Connector uses FML.

- Oracle WebLogic Tuxedo Connector JATMI VIEWs, provides information on View buffers and how to define and manage them in your applications.

- How to Create a Custom AppKey Plug-in, provides information on how to develop a Custom AppKey Plug-in.

- Application Error Management, provide mechanisms to manage and interpret error conditions.

1.2 Developing Oracle WebLogic Tuxedo Connector Applications

Note:

For more information on the Oracle WebLogic Tuxedo Connector JATMI, view the Javadocs for WebLogic Classes. The Oracle WebLogic Tuxedo Connector classes are located in the weblogic.wtc.jatmi and weblogic.wtc.gwt packages.

In addition to the Java code that expresses the logic of your application, you will be using the Java Application -to-Transaction Monitor Interface (JATMI) to provide the interface between Oracle WebLogic Server and Oracle Tuxedo.

1.2.1 Developing Oracle WebLogic Tuxedo Connector Clients

Note:

For more information, see Developing Oracle WebLogic Tuxedo Connector Client EJBs.

A client process takes user input and sends a service request to a server process that offers the requested service. Oracle WebLogic Tuxedo Connector JATMI client classes are used to create clients that access services found in Oracle Tuxedo. These client classes are available to any service that is made available through a the Oracle WebLogic Tuxedo Connector WTCServer MBean.

1.2.2 Developing Oracle WebLogic Tuxedo Connector Servers

Note:

For more information, see Developing Oracle WebLogic Tuxedo Connector Service EJBs.

Servers are processes that provide one or more services. They continually check their message queue for service requests and dispatch them to the appropriate service subroutines. Oracle WebLogic Tuxedo Connector uses EJBs to implement services which Oracle Tuxedo clients invoke.

1.2.3 Oracle WebLogic Tuxedo Connector Interoperability with Oracle Tuxedo CORBA objects

Note:

For more information, see Using Oracle WebLogic Tuxedo Connector for RMI/IIOP and CORBA Interoperability.

The Oracle WebLogic Tuxedo Connector provides bi-directional interoperability between Oracle WebLogic Server and Oracle Tuxedo CORBA objects. The Oracle WebLogic Tuxedo Connector:

- Enables Oracle Tuxedo CORBA objects to invoke upon EJBs deployed in Oracle WebLogic Server using the RMI/IIOP API (Inbound).

- Enables objects (such as EJBs or RMI objects) to invoke upon CORBA objects deployed in Oracle Tuxedo using the RMI/IIOP API (Outbound).

- Enables objects (such as EJBs or RMI objects) to invoke upon CORBA objects deployed in Oracle Tuxedo using a CORBA Java API (Outbound).

1.3 Oracle WebLogic Tuxedo Connector JATMI Primitives

The JATMI is a set of primitives used to begin and end transactions, allocate and free buffers, and provide the communication between clients and servers.

Table 1-1 JATMI Primitives

Name

Operation

tpacall

Use for asynchronous invocations of an Oracle Tuxedo service during request/response communication.tpacall has two forms:

- deferred synchronous

- asynchronous

tpacall

Use for synchronous invocation of an Oracle Tuxedo service during request/response communication.

tpconnect

Use to establish a connection to an Oracle Tuxedo conversational service.

tpdiscon

Use to abort a conversational connection and generate a TPEV_DISCONIMM event when executed by the process controlling the conversation.

tpdequeue

Use for receiving messages from an Oracle Tuxedo /Q during request/response communication.

tpenqueue

Use for placing a message on an Oracle Tuxedo /Q during request/response communication.

tpgetrply

Use for retrieving replies from an Oracle Tuxedo service during request/response communication.

tprecv

Use to receive data across an open connection from an Oracle Tuxedo application during conversational communication.

tpsend

Use to send data across a open connection to an Oracle Tuxedo application during conversational communication.

tpterm

Use to close a connection to an Oracle Tuxedo object.

1.4 Oracle WebLogic Tuxedo Connector TypedBuffers

Oracle WebLogic Tuxedo Connector provides an interface called TypedBuffers that corresponds to Oracle Tuxedo typed buffers. Messages are passed to servers in typed buffers. The Oracle WebLogic Tuxedo Connector provides the following buffer types:

Table 1-2 TypedBuffers

Buffer Type

Description

TypedString

Buffer type used when the data is an array of characters that terminates with the null character. Oracle Tuxedo equivalent: STRING.

TypedCArray

Buffer type used when the data is an undefined array of characters (byte array), any of which can be null. Oracle Tuxedo equivalent: CARRAY.

TypedFML

Buffer type used when the data is self-defined. Each data field carries its own identifier, an occurrence number, and possibly a length indicator. Oracle Tuxedo equivalent: FML.

TypedFML32

Buffer type similar to TypeFML but allows for larger character fields, more fields, and larger overall buffers. Oracle Tuxedo equivalent: FML32.

TypedXML

Buffer type used when data is an XML based message. Oracle Tuxedo equivalent: XML for Tuxedo Release 7.1 and higher.

TypedView

Buffer type used when the application uses a Java structure to define the buffer structure using a view description file. Oracle Tuxedo equivalent: VIEW

TypedView32

Buffer type similar to View but allows for larger character fields, more fields, and larger overall buffers. Oracle Tuxedo equivalent: VIEW32.

TypedMBString

Buffer type used when the data is a wide array of characters to support multi-byte characters. Oracle Tuxedo equivalent: MBSTRING.

1.5 New and Changed WTC Features for this Release

For a comprehensive listing of the new WebLogic Server features introduced in this release, see What's New in Oracle WebLogic Server 12.2.1.2.0.

2 Developing Oracle WebLogic Tuxedo Connector Client EJBs

This chapter describes how to create Oracle WebLogic Tuxedo Connector client EJBs. These client EJBs take user input and send service requests to a server process or outbound object that offers a requested service. Oracle WebLogic Tuxedo Connector JATMI client classes are used to create clients that access services found in Oracle Tuxedo.

This chapter includes the following sections:

- Joining and Leaving Applications

- Basic Client Operation

- Example Client EJB

Note:

For more information on the Oracle WebLogic Tuxedo Connector JATMI, view the Javadocs for WebLogic Classes. The Oracle WebLogic Tuxedo Connector classes are located in the weblogic.wtc.jatmi and weblogic.wtc.gwt packages.

2.1 Joining and Leaving Applications

Oracle Tuxedo and Oracle WebLogic Tuxedo Connector have different approaches to connect to services.

2.1.1 Joining an Application

The following section compares how Oracle Tuxedo and Oracle WebLogic Tuxedo Connector join an application:

- Oracle Tuxedo uses tpinit() to join an application.

- Oracle WebLogic Tuxedo Connector uses a WTCServer MBean to provide information required to create a path to the Oracle Tuxedo service. Security and client authentication is provided by configuring the Remote TDM and Imported Services MBean components of a WTCServer MBean. This pathway is created when the Oracle WebLogic Server is started and a WTCServer MBean is present in the config.xml file and assigned (targeted) to a server.

- Oracle WebLogic Tuxedo Connector uses TuxedoConnectionFactory to get a TuxedoConnection object and then uses getTuxedoConnection() to make a connection to the Oracle Tuxedo object. The following example shows how a Oracle WebLogic Server application joins an Oracle Tuxedo application using Oracle WebLogic Tuxedo Connector.

Example 2-1 Example Client Code to Join an Oracle Tuxedo Application

.
.
.
try {
ctx = new InitialContext();
tcf =
(TuxedoConnectionFactory)
ctx.lookup("tuxedo.services.TuxedoConnection");
} catch (NamingException ne) {

// Could not get the tuxedo object, throw TPENOENT
throw new TPException(TPException.TPENOENT,
"Could not get TuxedoConnectionFactory : " + ne);
}

myTux = tcf.getTuxedoConnection();
.
.
.

2.1.2 Leaving an Application

The following section compares how Oracle Tuxedo and Oracle WebLogic Tuxedo Connector leave an application:

- Oracle Tuxedo uses tpterm() to leave an application.

- Oracle WebLogic Tuxedo Connector uses the JATMI primitive tpterm() to close a connection to an Oracle Tuxedo object.

- Oracle WebLogic Tuxedo Connector closes the pathway to an Oracle Tuxedo service when a WTCServer MBean is assigned a new target server or the server is shutdown.

2.2 Basic Client Operation

A client process uses Java and JATMI primitives to provide the following basic application tasks:

- Get an Oracle Tuxedo Object

- Perform Message Buffering

- Send and Receive Messages

- Close a Connection to an Oracle Tuxedo Object

A client may send and receive any number of service requests before leaving the application.

2.2.1 Get an Oracle Tuxedo Object

Establish a connection to a remote domain by looking up tuxedo.services.TuxedoConnection in the JNDI tree to get TuxedoConnectionFactory, and use it to get a TuxedoConnection object.

2.2.2 Perform Message Buffering

Use the following TypedBuffers when sending and receiving messages between your application and Oracle Tuxedo:

Table 2-1 TypedBuffers

Buffer Type

Description

TypedString

Buffer type used when the data is an array of characters that terminates with the null character. Oracle Tuxedo equivalent: STRING.

TypedCArray

Buffer type used when the data is an undefined array of characters (byte array), any of which can be null. Oracle Tuxedo equivalent: CARRAY.

TypedFML

Buffer type used when the data is self-defined. Each data field carries its own identifier, an occurrence number, and possibly a length indicator. Oracle Tuxedo equivalent: FML.

TypedFML32

Buffer type similar to TypeFML but allows for larger character fields, more fields, and larger overall buffers. Oracle Tuxedo equivalent: FML32.

TypedXML

Buffer type used when data is an XML based message. Oracle Tuxedo equivalent: XML for Tuxedo Release 7.1 and higher.

TypedView

Buffer type used when the application uses a Java structure to define the buffer structure using a view description file. Oracle Tuxedo equivalent: View

TypedView32

Buffer type similar to View but allows for larger character fields, more fields, and larger overall buffers. Oracle Tuxedo equivalent: View32.

TypedMBString

Buffer type used when the data is a wide array of characters to support multi-byte characters. Oracle Tuxedo equivalent: MBSTRING.

2.2.3 Send and Receive Messages

Oracle WebLogic Tuxedo Connector clients support three types of communications with Oracle Tuxedo service applications:

- Request/Response Communication

- Conversational Communication

- Enqueuing and Dequeuing Messages

2.2.3.1 Request/Response Communication

Note:

Oracle WebLogic Tuxedo Connector does not provide a JATMI primitive to support setting the priority of a message request. All messages originating from a Oracle WebLogic Tuxedo Connector client have a message priority of 50.

Use the following JATMI primitives to request and receive response messages between your Oracle WebLogic Tuxedo Connector client application and Oracle Tuxedo:

Table 2-2 JATMI Primitives

Name

Operation

tpacall

Use for asynchronous invocations of an Oracle Tuxedo service.This JATMI primitive has two forms:

- deferred synchronous

- asynchronous

tpacall

Use for synchronous invocation of an Oracle Tuxedo service.

tpgetrply

Use for retrieving replies from deferred synchronous calls to an Oracle Tuxedo service.

tpcancel

Use to cancel an outstanding message reply for a call descriptor returned by tpacall.

Note: You can not use tpcancel to cancel a call descriptor associated with a transaction.

2.2.3.1.1 Using Synchronous Service Calls

Use tpcall to send a request to a service and synchronously await for the reply. The service specified must be advertised by your Oracle Tuxedo application. Logically, tpcall() has the same functionality as calling tpacall() and immediately calling tpgetreply().

2.2.3.1.2 Using Deferred Synchronous Service Calls

A deferred synchronous tpacall allows you to send a request to an Oracle Tuxedo service and not immediately wait for the reply. This allows you to send a request, perform other work, and then retrieve the reply.

A deferred tpacall() service call sends a request to an Oracle Tuxedo service and immediately returns from the call. The service specified must be advertised by your Oracle Tuxedo application. Upon successful completion of the call, tpacall() returns an object that serves as a descriptor. The calling thread is now available to perform other tasks. You can use the call descriptor to:

- Get the correct reply for the sent request using tpgetreply()

- Cancel an outstanding message reply using tpcancel().

When you are ready to retrieve the reply, use tpgetreply() to dequeue the reply using the call descriptor returned by tpacall(). If the reply is not immediately available, the calling thread polls for the reply.

If tpacall() is in a transaction, you must receive the reply using tpgetreply() before the transaction can commit. You can not use tpcancel to cancel a call descriptor associated with a transaction. For example: If you make three tpacall() requests in a transaction, you must make three tpgetreply() calls and successfully dequeue a reply for each of the three requests for the transaction to commit.

2.2.3.1.3 Using Asynchronous Calls

The asynchronous tpacall allows you to send a request to an Oracle Tuxedo service and release the thread resource that performed the call to the thread pool. This allows a very large number of outstanding requests to be serviced with a much smaller number of threads.

An asynchronous tpacall() service call sends a request to an Oracle Tuxedo service. The service specified must be advertised by your Oracle Tuxedo application. Upon successful completion of the call, asynchronous tpacall() returns an object that serves as a descriptor. The calling thread is now available to perform other tasks. You can use the call descriptor to identify the correct message reply from TpacallAsynchReply for a sent message request or cancel an outstanding message reply using tpcancel().

Note:

You can not use the call descriptor to invoke tpgetreply().

When the service reply is ready, the callback object is invoked on a different thread. If the original request succeeded, the TpacallAsynchReply.sucess method returns the reply from the service. If the original request failed, the TpacallAsynchReply.failure method returns a failure code.

You should implement the callback object using the following guidelines:

- The reply thread is obtained from the threadpool. The thread making the asynchronous tpacall() does not wait for the reply message.

- The user context of the reply thread will be restored to that of the original caller of asynchronous tpacall().

- It is up to the callback object to restore any additional context and resume whatever processing was interrupted when the original asynchronous tpacall() was made.

- It is up to you to synchronize work within the multi threaded environment. For example: If an asynchronous tpacall() request is made and the reply is returned immediately, it is possible for the call back object to be modified by the reply thread before the calling thread has finished.

- The reply thread will not retain the transaction context of the calling thread.

- If asynchronous tpacall() is in a transaction, you must receive the reply using TpacallAsynchReply before the transaction can commit. You can not use tpcancel to cancel a call descriptor associated with a transaction.

2.2.3.2 Conversational Communication

Note:

For more information on Conversational Communication, see Oracle WebLogic Tuxedo Connector JATMI Conversations.

Use the following conversational primitives when creating conversational clients that communicate with Oracle Tuxedo services:

Table 2-3 Oracle WebLogic Tuxedo Connector Conversational Client Primitives

Name

Operation

tpconnect

Use to establish a connection to an Oracle Tuxedo conversational service.

tpdiscon

Use to abort a connection and generate a TPEV_DISCONIMM event when executed by the process controlling the conversation.

tprecv

Use to receive data across an open connection from an Oracle Tuxedo application.

tpsend

Use to send data across an open connection to an Oracle Tuxedo application.

2.2.3.3 Enqueuing and Dequeuing Messages

Use the following JATMI primitives to enqueue and dequeue messages between your Oracle WebLogic Tuxedo Connector client application and Oracle Tuxedo:

Table 2-4 JATMI Primitives

Name

Operation

tpdequeue

Use for receiving messages from an Oracle Tuxedo /Q.

tpenqueue

Use for placing a message on an Oracle Tuxedo /Q.

2.2.4 Close a Connection to an Oracle Tuxedo Object

Use tpterm() to close a connection to an object and prevent future operations on this object.

2.3 Example Client EJB

The following Java code provides an example of the ToupperBean.java client EJB which sends a string argument to a server and receives a reply string from the server.

Example 2-2 Example Client Application

.
.
.
public String Toupper(String toConvert)
throws TPException, TPReplyException
{
Context ctx;
TuxedoConnectionFactory tcf;
TuxedoConnection myTux;
TypedString myData;
Reply myRtn;
int status;

log("toupper called, converting " + toConvert);

try {
ctx = new InitialContext();
tcf = (TuxedoConnectionFactory) ctx.lookup(
"tuxedo.services.TuxedoConnection");
}
catch (NamingException ne) {
// Could not get the tuxedo object, throw TPENOENT
throw new TPException(TPException.TPENOENT, "Could not get
TuxedoConnectionFactory : " + ne);
}

myTux = tcf.getTuxedoConnection();

myData = new TypedString(toConvert);

log("About to call tpcall");
try {
myRtn = myTux.tpcall("TOUPPER", myData, 0);
}
catch (TPReplyException tre) {
log("tpcall threw TPReplyExcption " + tre);
throw tre;
}
catch (TPException te) {
log("tpcall threw TPException " + te);
throw te;
}
catch (Exception ee) {
log("tpcall threw exception: " + ee);
throw new TPException(TPException.TPESYSTEM, "Exception: " + ee);
}
log("tpcall successfull!");

myData = (TypedString) myRtn.getReplyBuffer();

myTux.tpterm();// Closing the association with Tuxedo

return (myData.toString());
}
.
.
.

3 Developing Oracle WebLogic Tuxedo Connector Service EJBs

This chapter describes how to create Oracle WebLogic Tuxedo Connector service EJBs.

This chapter includes the following sections:

- Basic Service EJB Operation

- Example Service EJB

3.1 Basic Service EJB Operation

A service application uses Java and JATMI primitives to provide the following tasks:

- Access Service Information

- Buffer Messages

- Perform the Requested Service

3.1.1 Access Service Information

Use the TPServiceInformation class to access service information sent by the Oracle Tuxedo client to run the service.

Table 3-1 JATMI TPServiceInformation Primitives

Buffer Type

Description

getServiceData()

Use to return the service data sent from the Oracle Tuxedo Client.

getServiceFlags()

Use to return the service flags sent from the Oracle Tuxedo Client.

getServiceName()

Use to return the service name that was called.

3.1.2 Buffer Messages

Use the following TypedBuffers when sending and receiving messages between your application and Oracle Tuxedo:

Table 3-2 TypedBuffers

Buffer Type

Description

TypedString

Buffer type used when the data is an array of characters that terminates with the null character. Oracle Tuxedo equivalent: STRING.

TypedCArray

Buffer type used when the data is an undefined array of characters (byte array), any of which can be null. Oracle Tuxedo equivalent: CARRAY.

TypedFML

Buffer type used when the data is self-defined. Each data field carries its own identifier, an occurrence number, and possibly a length indicator. Oracle Tuxedo equivalent: FML.

TypedFML32

Buffer type similar to TypeFML but allows for larger character fields, more fields, and larger overall buffers. Oracle Tuxedo equivalent: FML32.

TypedXML

Buffer type used when data is an XML based message. Oracle Tuxedo equivalent: XML for Tuxedo Release 7.1 and higher.

TypedView

Buffer type used when the application uses a Java structure to define the buffer structure using a view description file. Tuxedo equivalent: VIEW

TypedView32

Buffer type similar to View but allows for larger character fields, more fields, and larger overall buffers. Oracle Tuxedo equivalent: VIEW32.

TypedXOctet

Buffer type used when the data is an undefined array of characters (byte array) any of which can be null. X_OCTET is identical in semantics to CARRAY. Oracle Tuxedo equivalent: X_OCTET.

TypedXCommon

Buffer type identical in semantics to View. Oracle Tuxedo equivalent: VIEW.

TypedXCType

Buffer type identical in semantics to View. Oracle Tuxedo equivalent: VIEW.

TypedMBString

Buffer type used when the data is a wide array of characters to support multi-byte characters. Oracle Tuxedo equivalent: MBSTRING.

3.1.3 Perform the Requested Service

Use Java code to express the logic required to provide your service.

3.1.3.1 Return Client Messages for Request/Response Communication

Use the TuxedoReply class setReplyBuffer() method to respond to client requests.

3.1.3.2 Use tpsend and tprecv for Conversational Communication

Note:

For more information on Conversational Communication, see Oracle WebLogic Tuxedo Connector JATMI Conversations.

Use the following JATMI primitives when creating conversational servers that communicate with Oracle Tuxedo clients:

Table 3-3 Oracle WebLogic Tuxedo Connector Conversational Client Primitives

Name

Operation

tpconnect

Use to establish a connection to an Oracle Tuxedo conversational service.

tpdiscon

Use to abort a connection and generate a TPEV_DISCONIMM event when executed by the process controlling the conversation.

tprecv

Use to receive data across an open connection from an Oracle Tuxedo application.

tpsend

Use to send data across a open connection to an Oracle Tuxedo application.

3.2 Example Service EJB

The following provides an example of the TolowerBean.java service EJB which receives a string argument, converts the string to all lower case, and returns the converted string to the client.

Example 3-1 Example Service EJB

.
.
.

public Reply service(TPServiceInformation mydata) throws TPException {
TypedString data;
String lowered;
TypedString return_data;

log("service tolower called");

data = (TypedString) mydata.getServiceData();
lowered = data.toString().toLowerCase();
return_data = new TypedString(lowered);

mydata.setReplyBuffer(return_data);
return (mydata);
}
.
.
.

4 Using Oracle WebLogic Tuxedo Connector for RMI/IIOP and CORBA Interoperability

This chapter describes how to modify applications to use Oracle WebLogic Tuxedo Connector to support interoperability between Oracle WebLogic Server and Oracle Tuxedo CORBA objects.

This chapter includes the following sections:

- How to Develop Oracle WebLogic Tuxedo Connector Client Beans using the CORBA Java API

- How to Develop RMI/IIOP Applications for the Oracle WebLogic Tuxedo Connector

- How to Use FederationURL Formats

- How to Manage Transactions for Oracle Tuxedo CORBA Applications

Note:

You will need to perform some administration tasks to configure the Oracle WebLogic Tuxedo Connector for CORBA interoperability. For information on how to administer the Oracle WebLogic Tuxedo Connector for CORBA interoperability, see Administration of Corba Applications in Administering WebLogic Tuxedo Connector for Oracle WebLogic Server.

For information on how to develop Oracle Tuxedo CORBA applications, see CORBA Programming at http://docs.oracle.com/cd/E13203_01/tuxedo/tux100/interm/corbaprog.html.

4.1 How to Develop Oracle WebLogic Tuxedo Connector Client Beans using the CORBA Java API

The Oracle WebLogic Tuxedo Connector enables objects (such as EJBs or RMI objects) to invoke upon CORBA objects deployed in Oracle Tuxedo using the CORBA Java API (Outbound). Oracle WebLogic Tuxedo Connector implements a WTC ORB which uses Oracle WebLogic Server RMI-IIOP runtime and CORBA support. This enhancement provides the following features:

- Support of out and inout parameters

- Support for a call a CORBA service from Oracle WebLogic Server using transactions and security.

- Support for an ORB hosted in JNDI rather than an instance of the JDK ORB used in previous releases.

- A wrapper is provided to allow users with legacy applications to use the new ORB without modifying their existing applications. Oracle recommends that users migrate to the new method of looking up the ORB in JNDI instead of doing:

ORB orb = ORB.init(args, Prop);

To use CORBA Java API, you must use the WTC ORB. Use one of the following methods to obtain an ORB in your Bean:

Properties Prop;
Prop = new Properties();
Prop.put("org.omg.CORBA.ORBClass","weblogic.wtc.corba.ORB");
ORB orb = ORB.init(new String[0], Prop);

or

ORB orb = (ORB)(new InitialContext().lookup("java:comp/ORB"));

or

ORB orb = ORB.init();

You can use either of the following methods to reference objects deployed in Oracle Tuxedo:

- Using CosNaming Service

- Using FactoryFinder

4.1.1 Using CosNaming Service

Note:

For more information on object references, see How to Use FederationURL Formats.

1. The Oracle WebLogic Tuxedo Connector uses the CosNaming service to get a reference to an object in the remote Oracle Tuxedo CORBA domain. This is accomplished by using a corbaloc:tgiop or corbaname:tgiop object reference. The following statements use the CosNaming service to get a reference to an Oracle Tuxedo CORBA Object:

// Get the simple factory.
org.omg.CORBA.Object simple_fact_oref =
orb.string_to_object("corbaname:tgiop:simpapp#simple_factory");

Where:

- simpapp is the domain id of the Oracle Tuxedo domain specified in the Oracle Tuxedo UBB.

- simple_factory is the name that the object reference was bound to in the Oracle Tuxedo CORBA CosNaming server.

4.1.1.1 Example ToupperCorbaBean.java Code

Note:

For an example on how to develop client beans for outbound Oracle Tuxedo CORBA objects, see the ORACLE_HOME\wlserver\samples\server\wtc\corba\simpappcns package in your Oracle WebLogic Server examples distribution. For more information on the WebLogic Server code examples, see Sample Applications and Code Examples in Understanding Oracle WebLogic Server.

The following ToupperCorbaBean.java code provides an example of how to call the WTC ORB and get an object reference using the COSNaming Service.

Example 4-1 Example Service Application

.
.
.
public String Toupper(String toConvert)
throws RemoteException
{
log("toupper called, converting " + toConvert);

try {
// Initialize the ORB.
String args[] = null;
Properties Prop;
Prop = new Properties();
Prop.put("org.omg.CORBA.ORBClass",
"weblogic.wtc.corba.ORB");

ORB orb = (ORB) new InitialContext().lookup("java:comp/ORB");

// Get the simple factory.
org.omg.CORBA.Object simple_fact_oref =
orb.string_to_object("corbaname:tgiop:simpapp#simple_factory");

//Narrow the simple factory.
SimpleFactory simple_factory_ref =
SimpleFactoryHelper.narrow(simple_fact_oref);

// Find the simple object.
Simple simple = simple_factory_ref.find_simple();

// Convert the string to upper case.
org.omg.CORBA.StringHolder buf =
new org.omg.CORBA.StringHolder(toConvert);
simple.to_upper(buf);
return buf.value;
}
catch (Exception e) {
throw new RemoteException("Can't call TUXEDO CORBA server: " +e);
}
}
.
.
.

4.1.2 Using FactoryFinder

Note:

For more information on object references, see How to Use FederationURL Formats.

Oracle WebLogic Tuxedo Connector provides support for FactoryFinder objects using the find_one_factory_by_id method. This is accomplished by using a corbaloc:tgiop or corbaname:tgiop object reference. Use the following method to obtain the FactoryFinder object using the ORB:

// String to Object.
org.omg.CORBA.Object fact_finder_oref =
orb.string_to_object("corbaloc:tgiop:simpapp/FactoryFinder");

// Narrow the factory finder.
FactoryFinder fact_finder_ref =
FactoryFinderHelper.narrow(fact_finder_oref);

// Use the factory finder to find the simple factory.
org.omg.CORBA.Object simple_fact_oref =
fact_finder_ref.find_one_factory_by_id(SimpleFactoryHelper.id());

Where:

- simpapp is the domain id of the Oracle Tuxedo domain specified in the Oracle Tuxedo UBB.

- FactoryFinder is the name that the object reference was bound to in the Oracle Tuxedo CORBA server.

4.1.2.1 WLEC to Oracle WebLogic Tuxedo Connector Migration

WLEC is no longer available or supported in Oracle WebLogic Server. WLEC users should migrate their applications to Oracle WebLogic Tuxedo Connector.

4.1.2.2 Example Code

The following code provides an example of how to call the WTC ORB and get an object reference using FactoryFinder.

Example 4-2 Example FactoryFinder Code

.
.
.
public ConverterResult convert (String changeCase, String mixed)
throws ProcessingErrorException
{
String result;
try {
// Initialize the ORB.
String args[] = null;
Properties Prop;
Prop = new Properties();
Prop.put("org.omg.CORBA.ORBClass","weblogic.wtc.corba.ORB");
ORB orb = (ORB)new InitialContext().lookup("java:comp/ORB");

org.omg.CORBA.Object fact_finder_oref =
orb.string_to_object("corbaloc:tgiop:simpapp/FactoryFinder");

// Narrow the factory finder.
FactoryFinder fact_finder_ref =
FactoryFinderHelper.narrow(fact_finder_oref);

// find_one_factory_by_id
org.omg.CORBA.Object simple_fact_oref =
fact_finder_ref.find_one_factory_by_id(FactoryFinderHelper.id());

// Narrow the simple factory.
SimpleFactory simple_factory_ref =
SimpleFactoryHelper.narrow(simple_fact_oref);

// Find the simple object.
Simple simple = simple_factory_ref.find_simple();

if (changeCase.equals("UPPER")) {
// Invoke the to_upper opeation on M3 Simple object
org.omg.CORBA.StringHolder buf =
new org.omg.CORBA.StringHolder(mixed);
simple.to_upper(buf);
result = buf.value;
}
else
{
result = simple.to_lower(mixed);
}

}
catch (org.omg.CORBA.SystemException e) {e.printStackTrace();

throw new ProcessingErrorException("Converter error: Corba system exception: " + e);
}
catch (Exception e) {
e.printStackTrace();
throw new ProcessingErrorException("Converter error: " + e);
}
return new ConverterResult(result);
}
.
.
.

4.2 How to Develop RMI/IIOP Applications for the Oracle WebLogic Tuxedo Connector

Note:

For more information on how to develop RMI/IIOP applications, see Developing RMI Applications for Oracle WebLogic Server.

RMI over IIOP (Internet Inter-ORB Protocol) extends RMI so that Java programs can interact with Common Object Request Broker Architecture (CORBA) clients and execute CORBA objects. The Oracle WebLogic Tuxedo Connector:

- Enables Oracle Tuxedo CORBA objects to invoke upon EJBs deployed in Oracle WebLogic Server (Inbound).

- Enables objects (such as EJBs or RMI objects) to invoke upon CORBA objects deployed in Oracle Tuxedo (Outbound).

The following sections provide information on how to modify RMI/IIOP applications to use the Oracle WebLogic Tuxedo Connector to interoperate with Oracle Tuxedo CORBA applications:

- How to Modify Inbound RMI/IIOP Applications to use the Oracle WebLogic Tuxedo Connector

- How to Develop Outbound RMI/IIOP Applications to use the Oracle WebLogic Tuxedo Connector

4.2.1 How to Modify Inbound RMI/IIOP Applications to use the Oracle WebLogic Tuxedo Connector

A client must pass the correct name to which the Oracle WebLogic Server's name service has been bound to the COSNaming Service.

The following code provides an example for obtaining a naming context. "WLS" is the bind name specified in the cnsbind command detailed in Administration of Corba Applications in Administering WebLogic Tuxedo Connector for Oracle WebLogic Server.

Example 4-3 Example Code to Obtain a Naming Context

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.
.
// obtain a naming context
TP::userlog("Narrowing to a naming context");
CosNaming::NamingContext_var context =
CosNaming::NamingContext::_narrow(o);
CosNaming::Name name;
name.length(1);
name[0].id = CORBA::string_dup("WLS");
name[0].kind = CORBA::string_dup("");
.
.
.

4.2.2 How to Develop Outbound RMI/IIOP Applications to use the Oracle WebLogic Tuxedo Connector

An EJB must use a FederationURL to obtain the initial context used to access a remote Oracle Tuxedo CORBA object. Use the following sections to modify outbound RMI/IIOP applications to use the Oracle WebLogic Tuxedo Connector:

- How to Modify the ejb-jar.xml File to Pass a FederationURL to EJBs

- How to Modify EJBs to Use FederationURL to Access an Object

4.2.2.1 How to Modify the ejb-jar.xml File to Pass a FederationURL to EJBs

The following code provides an example of how to configure an ejb-jar.xml file to pass a FederationURL format to the EJB at run-time.

Example 4-4 Example ejb-jar.xml File Passing a FederationURL to an EJB

<?xml version="1.0"?>

<!DOCTYPE ejb-jar PUBLIC '-//Sun Microsystems, Inc.//DTD Enterprise JavaBeans
1.1//EN' 'http://java.sun.com/j2ee/dtds/ejb-jar_1_1.dtd'>

<ejb-jar>
<small-icon>images/green-cube.gif</small-icon>
<enterprise-beans>
<session>
<small-icon>images/orange-cube.gif</small-icon>
<ejb-name>IIOPStatelessSession</ejb-name>
<home>examples.iiop.ejb.stateless.TraderHome</home>
<remote>examples.iiop.ejb.stateless.Trader</remote>
<ejb-class>examples.iiop.ejb.stateless.TraderBean</ejb-class>
<session-type>Stateless</session-type>
<transaction-type>Container</transaction-type>
<env-entry>
<env-entry-name>foreignOrb</env-entry-name>
<env-entry-type>java.lang.String </env-entry-type>
<env-entry-value>corbaloc:tgiop:simpapp</env-entry-value>
</env-entry>
<env-entry>
<env-entry-name>WEBL</env-entry-name>
<env-entry-type>java.lang.Double </env-entry-type>
<env-entry-value>10.0</env-entry-value>
</env-entry>
<env-entry>
<env-entry-name>INTL</env-entry-name>
<env-entry-type>java.lang.Double </env-entry-type>
<env-entry-value>15.0</env-entry-value>
</env-entry>
<env-entry>
<env-entry-name>tradeLimit</env-entry-name>
<env-entry-type>java.lang.Integer </env-entry-type>
<env-entry-value>500</env-entry-value>
</env-entry>
</session>
</enterprise-beans>
<assembly-descriptor>
<container-transaction>
<method>
<ejb-name>IIOPStatelessSession</ejb-name>
<method-intf>Remote</method-intf>
<method-name>*</method-name>
</method>
<trans-attribute>NotSupported</trans-attribute>
</container-transaction>
</assembly-descriptor>
</ejb-jar>

To pass the FederationURL to the EJB at run-time, add an env-entry for the EJB in the ejb-jar.xml file for your application. You must assign the following env-entry sub-elements:

- Assign env-entry-name

- Assign env-entry-type

- Assign env-entry-value

4.2.2.1.1 Assign env-entry-name

The env-entry-name element is used to specify the name of the variable used to pass the value in the env-entry-value element to the EJB. The example code shown in Example 4-4 specifies the env-entry-name as foreignOrb.

4.2.2.1.2 Assign env-entry-type

The env-entry-type element is used to specify the data type (example String, Integer, Double) of the env-entry-value element that is passed to the EJB. The example code shown in Example 4-4 specifies that the foreignOrb variable passes String data to the EJB.

4.2.2.1.3 Assign env-entry-value

The env-entry-value element is used to specify the data that is passed to the EJB. The example code shown in Example 4-4 specifies that the foreignOrb variable passes the following FederationURL format to the EJB:

corbaloc:tgiop:simpapp

Where simpapp is the DOMAINID of the Oracle Tuxedo remote service specified in the Oracle Tuxedo UBB.

4.2.2.2 How to Modify EJBs to Use FederationURL to Access an Object

This section provides information on how to use the FederationURL to obtain the InitialContext used to access a remote Oracle Tuxedo CORBA object.

The following code provides an example of how to use FederationURL to get an InitialContext.

1. Retrieve the FederationURL format defined in the ejb-jar.xml file.

Example:

"ic.lookup("java:/comp/env/foreignOrb")

The example code shown in Example 4-4 specifies that the foreignOrb variable passes the following FederationURL format to the EJB:

corbaloc:tgiop:simpapp

2. Concatenate the FederationURL format with "/NameService" to form the FederationURL.

Example:

"ic.lookup("java:/comp/env/foreignOrb") + "/NameService"

The resulting FederationURL is:

corbaloc:tgiop:simpapp/NameService

3. Get the InitialContext.

Example:

env.put(Context.PROVIDER_URL, (String)
ic.lookup("java:/comp/env/foreignOrb") + "/NameService");
InitialContext cos = new InitialContext(env);

The result is the InitialContext of the Oracle Tuxedo CORBA object.

Example 4-5 Example TraderBean.java Code to get InitialContext

.
.
.
public void createRemote() throws CreateException {
log("createRemote() called");

try {
InitialContext ic = new InitialContext();

// Lookup a EJB-like CORBA server in a remote CORBA domain
Hashtable env = new Hashtable();
env.put(Context.PROVIDER_URL, (String)
ic.lookup("java:/comp/env/foreignOrb")
+ "/NameService");

InitialContext cos = new InitialContext(env);
TraderHome thome =
(TraderHome)PortableRemoteObject.narrow(
cos.lookup("TraderHome_iiop"),TraderHome.class);
remoteTrader = thome.create();
}
catch (NamingException ne) {
throw new CreateException("Failed to find value "+ne);
}
catch (RemoteException re) {
throw new CreateException("Error creating remote ejb "+re);
}
}
.
.
.

Use the following steps to use FederationURL to obtain an InitialContext for a remote Oracle Tuxedo CORBA object:

4.3 How to Use FederationURL Formats

This section provides information on the syntax for the following FederationURL formats:

- The CORBA URL syntax is described in the CORBA specification. For more information, see the OMG Web Site at http://www.omg.org/.

- The corbaloc:tgiop form is specific to the Oracle tgiop protocol.

4.3.1 Using corbaloc URL Format

This section provides the syntax for corbaloc URL format:

<corbaloc> = "corbaloc:tgiop":[<version>] <domain>["/"<key_string>]
<version> = <major> "." <minor> "@" | empty_string
<domain> = TUXEDO CORBA domain name
<major> = number
<minor> = number
<key_string> = <string> | empty_string

4.3.1.1 Examples of corbaloc:tgiop

This section provides examples on how to use corbaloc:tgiop.

orb.string_to_object("corbaloc:tgiop:simpapp/NameService");
orb.string_to_object("corbaloc:tgiop:simpapp/FactoryFinder");
orb.string_to_object("corbaloc:tgiop:simpapp/InterfaceRepository");
orb.string_to_object("corbaloc:tgiop:simpapp/Tobj_SimpleEventsService");
orb.string_to_object("corbaloc:tgiop:simpapp/NotificationService");
orb.string_to_object("corbaloc:tgiop:1.1@simpapp/NotificationService);

4.3.1.2 Examples using -ORBInitRef

You can also use the -ORBInitRef option to orb.init and resolve_initial_reference.

Given the following -ORBInitRef definitions:

-ORBInitRef FactoryFinder=corbaloc:tgiop:simp/FactoryFinder
-ORBInitRef InterfaceRepository=corbaloc:tgiop:simp/InterfaceRepository
-ORBInitRef Tobj_SimpleEventService=corbaloc:tgiop:simp/Tobj_SimpleEventsService
-ORBInitRef NotificationService=corbaloc:tgiop:simp/NotificationService

then:

orb.resolve_initial_references("NameService");
orb.resolve_initial_references("FactoryFinder");
orb.resolve_initial_references("InterfaceRepository");
orb.resolve_initial_references("Tobj_SimpleEventService");
orb.resolve_initial_references("NotificationService");

4.3.1.3 Examples Using -ORBDefaultInitRef

You can use the -ORBDefaultInitRef and resolve_initial_reference.

Given the following -ORBDefaultInitRef definition:

-ORBDefaultInitRef corbaloc:tgiop:simpapp

then:

orb.resolve_initial_references("NameService");

4.3.2 Using the corbaname URL Format

You can also use the corbaname format instead of the corbaloc format.

4.3.2.1 Examples Using -ORBInitRef

Given the following -ORBInitRef definition:

-ORBInitRef NameService=corbaloc:tgiop:simpapp/NameService

then:

orb.string_to_object("corbaname:rir:#simple_factory");
orb.string_to_object("corbaname:tgiop:simpapp#simple_factory");
orb.string_to_object("corbaname:tgiop:1.1@simpapp#simple_factory");
orb.string_to_object("corbaname:tgiop:simpapp#simple/simple_factory");

4.4 How to Manage Transactions for Oracle Tuxedo CORBA Applications

Note:

For more information on managing transactions in Oracle Tuxedo CORBA applications, see Overview of Transactions in Tuxedo CORBA Applications in Using CORBA Transactions at http://docs.oracle.com/cd/E13203_01/tuxedo/tux100/trans/gstrx.html.

The Oracle WebLogic Tuxedo Connector uses the Java Transaction API (JTA) to manage transactions with Oracle Tuxedo Corba Applications. For more detailed information, see:

- Developing JTA Applications for Oracle WebLogic Server

- Transaction Design and Management Options in Developing Enterprise JavaBeans, Version 2.1, for Oracle WebLogic Server

5 Oracle WebLogic Tuxedo Connector JATMI Transactions

This chapter describes how to define and manage Oracle WebLogic Tuxedo Connector global transactions using the Java Transaction API (JTA).

This chapter includes the following sections:

- Global Transactions

- JTA Transaction API

- Defining a Transaction

- Oracle WebLogic Tuxedo Connector Transaction Rules

- Example Transaction Code

5.1 Global Transactions

A global transaction is a transaction that allows work involving more than one resource manager and spanning more than one physical site to be treated as one logical unit. A global transaction is always treated as a specific sequence of operations that is characterized by the following four properties:

- Atomicity: All portions either succeed or have no effect.

- Consistency: Operations are performed that correctly transform the resources from one consistent state to another.

- Isolation: Intermediate results are not accessible to other transactions, although other processes in the same transaction may access the data.

- Durability: All effects of a completed sequence cannot be altered by any kind of failure.

5.2 JTA Transaction API

Note:

For more detailed information, see the JTA API at http://www.oracle.com/technetwork/java/javaee/jta/index.html.

The Oracle WebLogic Tuxedo Connector uses the Java Transaction API (JTA) to manage transactions.

5.2.1 Types of JTA Interfaces

JTA offers three types of transaction interfaces:

- Transaction

- TransactionManager

- UserTransaction

5.2.1.1 Transaction

The Transaction interface allows operations to be performed against a transaction in the target Transaction object. A transaction object is created to correspond to each global transaction created. Use the Transaction interface to enlist resources, synchronize registration, and perform transaction completion and status query operations.

5.2.1.2 TransactionManager

The TransactionManager interface allows the application server to communicate to the Transaction Manager for transaction boundaries demarcation on behalf of the application. Use the TransactionManager interface to communicate to the transaction manager on behalf of container-managed EJB components.

5.2.1.3 UserTransaction

The UserTransaction interface is a subset of the TransactionManager interface. Use the UserTransaction interface when it is necessary to restrict access to Transaction object.

5.2.2 JTA Transaction Primitives

The following table maps the functionality of Oracle Tuxedo transaction primitives to equivalent JTA transaction primitives.

Table 5-1 Mapping Oracle Tuxedo Transaction Primitives to JTA Equivalents

Oracle Tuxedo

Oracle Tuxedo Functionality

JTA Equivalent

tpabort

Use to end a transaction.

or rollback

tpcommit

Use to complete a transaction.

commit

tpgetlev

Use to determine if a service routine is in transaction mode.

getStatus

tpbegin

Use to begin a transaction.

setTransactionTimeout
begin

5.3 Defining a Transaction

Transactions can be defined in either client or server processes. A transaction has three parts: a starting point, the program statements that are in transaction mode, and a termination point.

To explicitly define a transaction, call the begin() method. The same process that makes the call, the initiator, must also be the one that terminates it by invoking a commit(), setRollbackOnly(), or rollback(). Any service subroutines that are called between the transaction delimiter become part of the current transaction.

5.3.1 Starting a Transaction

Note:

Setting setTransactionTimeout() to unrealistically large values delays system detection and reporting of errors. Use time-out values to ensure response to service requests occur within a reasonable time and to terminate transactions that have encountered problem, such as a network failure. For productions environments, adjust the time-out value to accommodate expected delays due to system load and database contention.

A transaction is started by a call to begin(). To specify a time-out value, precede the begin() statement with a setTransactionTimeout(int seconds) statement.

To propagate the transaction to Oracle Tuxedo, you must do the following:

- Look up a TuxedoConnectionFactory object in the JNDI.

- Get a TuxedoConnection object using getTuxedoConnection().

5.3.1.1 Using TPNOTRAN

Service routines that are called within the transaction delimiter are part of the current transaction. However, if tpcall() or tpacall() have the flags parameter set to TPNOTRAN, the operations performed by the called service do not become part of that transaction. As a result, services performed by the called process are not affected by the outcome of the current transaction.

5.3.2 Terminating a Transaction

A transaction is terminated by a call to commit(), rollback(), or setRollbackOnly(). When commit() returns successfully, all changes to the resource as a result of the current transaction become permanent. In order for a commit() to succeed, the following two conditions must be met:

- The calling process must be the same one that initiated the transaction with a begin()

- The calling process must have no transaction replies outstanding

If either condition is not true, the call fails and an exception is thrown.

setRollbackOnly() and rollback() are used to indicate an abnormal condition and to roll back any call descriptors to their original state.

- Use setRollbackOnly() if further processing or cleanup is needed before rolling back the transaction.

- Use rollback() if no further processing or cleanup is required before rolling back the transaction.

5.4 Oracle WebLogic Tuxedo Connector Transaction Rules

You must follow certain rules while in transaction mode to insure successful completion of a transaction. The basic rules of etiquette that must be observed while in a transaction mode follow:

- You must propagate the transaction to Oracle Tuxedo using a TuxedoConnection object after you initiate a transaction with a begin().

- tpterm() closes a connection to an object and prevents future operations on this object.

- Processes that are participants in the same transaction must require replies for their requests.

- Requests requiring no reply can be made only if the flags parameter of tpacall() is set to TPNOREPLY.

- A service must retrieve all asynchronous transaction replies before calling commit().

- The initiator must retrieve all asynchronous transaction replies before calling begin().

- The asynchronous replies that must be retrieved include those that are expected from non-participants of the transaction, that is, replies expected for requests made with a tpacall() suppressing the transaction but not the reply.

- If a transaction has not timed out but is marked abort-only, further communication should be performed with the TPNOTRAN flag set so that the work done as a result of the communication has lasting effect after the transaction is rolled back.

- If a transaction has timed out:

- the descriptor for the timed out call becomes stale and any further reference to it will return TPEBADDESC.

- further calls to tpgetrply() or tprecv() for any outstanding descriptors will return the global state of transaction time-out by setting tperrono to TPETIME.

- asynchronous calls can be make with the flags parameter of tpacall() set to TPNOREPLY | TPNOBLOCK | TPNOTRAN.

- Once a transaction has been marked abort-only for reasons other than time-out, a call to tpgetrply() will return whatever represents the local state of the call, that is, it can either return success or an error code that represents the local condition.

- Once a descriptor is used with tpgetrply() to retrieve a reply, it becomes invalid and any further reference to it will return TPEBADDESC.

- Once a descriptor is used with tpsend() or tprecv() to report an error condition, it becomes invalid and any further reference to it will return TPEV_DISCONIMM.

- Once a transaction is aborted, all outstanding transaction call descriptions (made without the TPNOTRAN flag) become stale, and any further reference to them will return TPEBADDESC.

- Oracle WebLogic Tuxedo Connector does not guarantee that all calls for a particular transaction Id are routed to a particular server instance when load balancing. Load balancing is performed on a per call basis.

5.5 Example Transaction Code

The following provides a code example for a transaction:

Example 5-1 Example Transaction Code

public class TransactionSampleBean implements SessionBean {

.....

public int transaction_sample () {

int ret = 0;
try {
javax.naming.Context myContext = new InitialContext();
TransactionManager tm = (javax.transaction.TransactionManager)
myContext.lookup("javax.transaction.TransactionManager");

// Begin Transaction
tm.begin ();

TuxedoConnectionFactory tuxConFactory = (TuxedoConnectionFactory)
ctxt.lookup("tuxedo.services.TuxedoConnection");

// You could do a local JDBC/XA-database operation here
// which will be part of this transaction.
.....

// NOTE 1: Get the Tuxedo Connection only after
// you begin the transaction if you want the
// Tuxedo call to be part of the transaction!

// NOTE 2: If you get the Tuxedo Connection before
// the transaction was started, all calls made from
// that Tuxedo Connection are out of scope of the
// transaction.

TuxedoConnection myTux = tuxConFactory.getTuxedoConnection();

// Do a tpcall. This tpcall is part of the transaction.
TypedString depositData = new TypedString("somecharacters,5000.00");

Reply depositReply = myTux.tpcall("DEPOSIT", depositData, 0);

// You could also do tpcalls which are not part of
// transaction (For example, Logging all attempted
// operations etc.) by setting the TPNOTRAN Flag!
TypedString logData =
new TypedString("DEPOSIT:somecharacters,5000.00");

Reply logReply = myTux.tpcall("LOGTRAN", logData,
ApplicationToMonitorInterface.TPNOTRAN);

// Done with the Tuxedo Connection. Do tpterm.
myTux.tpterm ();

// Commit Transaction...
tm.commit ();

// NOTE: The TuxedoConnection object which has been
// used in this transaction, can be used after the
// transaction only if TPNOTRAN flag is set.
}
catch (NamingException ne) {
System.out.println ("ERROR: Naming Exception looking up JNDI: " + ne);
ret = -1;
}
catch (RollbackException re) {
System.out.println("ERROR: TRANSACTION ROLLED BACK: " + re);
ret = 0;
}
catch (TPException te) {
System.out.println("ERROR: tpcall failed: TpException: " + te);
ret = -1;
}
catch (Exception e) {
log ("ERROR: Exception: " + e);
ret = -1;
}

return ret;
}

6 Oracle WebLogic Tuxedo Connector JATMI Conversations

This chapter describes how to define and manage Oracle Tuxedo conversations in your applications. Tuxedo conversations are a supported method for message exchange between Oracle WebLogic Server and Oracle Tuxedo applications.

This chapter includes the following sections:

- Overview of Oracle WebLogic Tuxedo Connector Conversational Communication

- Oracle WebLogic Tuxedo Connector Conversation Characteristics

- Oracle WebLogic Tuxedo Connector JATMI Conversation Primitives

- Creating Oracle WebLogic Tuxedo Connector Conversational Clients and Servers

- Sending and Receiving Messages

- Ending a Conversation

- Executing a Disorderly Disconnect

- Understanding Conversational Communication Events

- Oracle WebLogic Tuxedo Connector Conversation Guidelines

Note:

For more information on conversational communications for Oracle Tuxedo, see Writing Conversational Clients and Servers in Programming a Tuxedo ATMI Application in C at http://docs.oracle.com/cd/E13203_01/tuxedo/tux100/pgc/pgconv.html.

6.1 Overview of Oracle WebLogic Tuxedo Connector Conversational Communication

Oracle WebLogic Tuxedo Connector supports Oracle Tuxedo conversations as a method to exchange messages between Oracle WebLogic Server and Oracle Tuxedo applications. In this form of communication, a virtual connection is maintained between the client and the server and each side maintains information about the state of the conversation. The process that opens a connection and starts a conversation is the originator of the conversation. The process with control of the connection is the initiator; the process without control is called the subordinate. The connection remains active until an event occurs to terminate it.

During conversational communication, a half-duplex connection is established between the initiator and the subordinate. Control of the connection is passed between the initiator and the subordinate. The process that has control can send messages (the initiator); the process that does not have control can only receive messages (the subordinate).

6.2 Oracle WebLogic Tuxedo Connector Conversation Characteristics

Oracle WebLogic Tuxedo Connector JATMI conversations have the following characteristics:

- Data is passed using TypedBuffers. The type and sub-type of the data must match one of the types and sub-types recognized by the service.

- The logical connection between the conversational client and the conversational server remains active until it is terminated.

- Any number of messages can be transmitted across a connection between a conversational client and the conversational server.

- A Oracle WebLogic Tuxedo Connector conversational client initiates a request for service using tpconnect rather than a tpcall or tpacall.

- Oracle WebLogic Tuxedo Connector conversational clients and servers use the JATMI primitives tpsend to send data and tprecv to receive data.

- A conversational client only sends service requests to a conversational server.

- Conversational servers are prohibited from making calls to tpforward.

6.3 Oracle WebLogic Tuxedo Connector JATMI Conversation Primitives

Use the following Oracle WebLogic Tuxedo Connector primitives when creating conversational clients and servers that communicate between Oracle WebLogic Server and Oracle Tuxedo:

Table 6-1 Oracle WebLogic Tuxedo Connector Conversational Client Primitives

Name

Operation

tpconnect

Use to establish a connection to an Oracle Tuxedo conversational service.

tpdiscon

Use to abort a connection and generate a TPEV_DISCONIMM event.

tprecv

Use to receive data across an open connection from an Oracle Tuxedo application.

tpsend

Use to send data across a open connection to an Oracle Tuxedo application.

6.4 Creating Oracle WebLogic Tuxedo Connector Conversational Clients and Servers

The following sections provide information on how to create conversational clients and servers.

6.4.1 Creating Conversational Clients

Follow the steps outlined in Developing Oracle WebLogic Tuxedo Connector Client EJBs to create Oracle WebLogic Tuxedo Connector conversational clients. The following section provide information on how to use tpconnect to open a connection and start a conversation.

6.4.1.1 Establishing a Connection to an Oracle Tuxedo Conversational Service

A Oracle WebLogic Tuxedo Connector conversational client must establish a connection to the Oracle Tuxedo conversational service. Use the JATMI primitive tpconnect to open a connection and start a conversation. A successful call returns an object that can be used to send and receive data for a conversation.

The following table describes tpconnect parameters:

Table 6-2 Oracle WebLogic Tuxedo Connector JATMI tpconnect Parameters

Parameter

Description

svc

Character pointer to a conversational service name. If you do not specify a svc, the call will fail and TPException is set to TPEV_DISCONIMM.

data

Pointer to the data buffer. When establishing a connection, you can send data simultaneously by setting the data parameter to point to a buffer. The type and subtype of the buffer must be recognized by the service being called. You can set the value of data to NULL to specify that no data is to be sent.

flags

Use flags or combinations of flags as required by your application needs. Valid flag values are:

TPSENDONLY: specifies that the control is being retained by the originator. The called service is subordinate and can only receive data. Do not use in combination with TPRECVONLY.

TPRECVONLY: specifies that control is being passed to the called service.The originator becomes subordinate and can only receive data. Do not use in combination with TPSENDONLY.

TPNOTRAN: specifies that when svc is invoked and the originator is transaction mode, svc is not part of the originator's transaction. A call remains subject to transaction timeouts. If svc fails, the originator's transaction is unaffected.

TPNOBLOCK: specifies that a request is not sent if a blocking condition exists. If TPNOBLOCK is not specified, the originator blocks until the condition subsides, a transaction timeout occurs, or a blocking timeout occurs.

TPNOTIME: specifies that the originator will block indefinitely and is immune to blocking timeouts. If the originator is in transaction mode, the call is subject to transaction timeouts.

6.4.1.2 Example TuxedoConversationBean.java Code

The following provides a code example to use tpconnect to start a conversation:

Example 6-1 Example Conversation Code

.
.
.
Context ctx;
Conversation myConv;
TuxedoConnection myTux;
TuxedoConnectionFactory tcf;
.
.
.
ctx = new InitialContext();
tcf = (TuxedoConnectionFactory) ctx.lookup ("tuxedo.services.TuxedoConnection");
myTux = tcf.getTuxedoConnection();
flags =ApplicationToMonitorInterface.TPSENDONLY;
myConv = myTux.tpconnect("CONNECT_SVC",null,flags);
.
.
.

6.4.2 Creating Oracle WebLogic Tuxedo Connector Conversational Servers

Follow the steps outlined in Developing Oracle WebLogic Tuxedo Connector Service EJBs, to create Oracle WebLogic Tuxedo Connector conversational servers.

6.5 Sending and Receiving Messages

Once a conversational connection is established between a Oracle WebLogic Server application and an Oracle Tuxedo application, the communication between the initiator (sends message) and subordinate (receives message) is accomplished using send and receive calls. The following sections describe how Oracle WebLogic Tuxedo Connector applications use the JATMI primitives tpsend and tprecv:

- Sending Messages

- Receiving Messages

6.5.1 Sending Messages

Use the JATMI primitive tpsend to send a message to an Oracle Tuxedo application.

The following table describes tpsend parameters:

Table 6-3 Oracle WebLogic Tuxedo Connector JATMI tpconnect Parameters

Parameter

Description

data

Pointer to the buffer containing the data sent with this conversation.

flags

The flag can be one of the following:

TPRECVONLY: specifies that after the initiator's data is sent, the initiator gives up control of the connection. The initiator becomes subordinate and can only receive data.

TPNOBLOCK: specifies that the request is not sent if a blocking condition exists. If TPNOBLOCK is not specified, the originator blocks until the condition subsides, a transaction timeout occurs, or a blocking timeout occurs.

TPNOTIME: specifies that an initiator is willing to block indefinitely and is immune from blocking timeouts. The call is subject to transaction timeouts.

6.5.2 Receiving Messages

Use the JATMI primitive tprecv to receive messages from an Oracle Tuxedo application.

The following table describes tprecv parameters:

Table 6-4 Oracle WebLogic Tuxedo Connector JATMI tprec Parameters

Parameter

Description

flags

The flag can be one of the following:

TPNOBLOCK: specifies that tprecv does not wait for a reply to arrive. If a reply is available, tprecv gets the reply and returns. If this flag is not specified and a reply is not available, tprecv waits for one of the following to occur: a reply, a transaction timeout, or a blocking timeout.

TPNOTIME: specifies that tprecv waits indefinitely for a reply. With this flag, tprecv is immuned from blocking timeouts but is still subject to transaction timeouts.

A flag value of 0 specifies that the initiator blocks until the condition subsides or a timeout occurs.

6.6 Ending a Conversation

A conversation between Oracle WebLogic Server and Oracle Tuxedo ends when the server process successfully completes its tasks. The following sections describe how a conversation ends:

- Oracle Tuxedo Application Originates Conversation

- Oracle WebLogic Tuxedo Connector Application Originates Conversation

- Ending Hierarchical Conversations

6.6.1 Oracle Tuxedo Application Originates Conversation

An Oracle WebLogic Server conversational server ends a conversation by a successful call to return. A TPEV_SVCSUCC event is sent to the Oracle Tuxedo client that originated connection to indicate that the service finished successfully. The connection is then disconnected in an orderly manner.

6.6.2 Oracle WebLogic Tuxedo Connector Application Originates Conversation

An Oracle Tuxedo conversational server ends a conversation by a successful call to tpreturn. A TPEV_SVCSUCC event is sent to the Oracle WebLogic Tuxedo Connector client that originated connection to indicate that the service finished successfully. The connection is then disconnected in an orderly manner.

6.6.3 Ending Hierarchical Conversations

The order in which an conversation ends is important to gracefully end hierarchal conversations.

Assume there are two active connections: A-B and B-C. If B is a Oracle WebLogic Tuxedo Connector application in control of both connections, a call to return has the following effect: the call fails and a TPEV_SVCERR event is posted on all open connections, and the connections are closed in a disorderly manner.

In order to terminate both connections in an orderly manner, the application must execute the following sequence:

1. B calls tpsend with TPRECVONLY to transfer control of the B-C connection to the Oracle Tuxedo application C.

2. C calls departure with rval set to TPSUCCESS, TPFAIL, or TPEXIT.

3. B calls return and posts an event (TPEV_SVCSUCC or TPEV_SVCFAIL) for A.

Conversational services can make request/response calls. Therefore, in the preceding example, the calls from B to C may be executed using tpacall() or tpcall() instead of tpconnect. Conversational services are not permitted to make calls to tpforward.

6.7 Executing a Disorderly Disconnect

Oracle WebLogic Server conversational clients or servers execute a disorderly disconnect is through a call to tpdiscon. This is the equivalent of "pulling the plug" on a connection.

A call to tpdiscon:

- Immediately tears down the connection and generates a TPEV_DISCONIMM at the other end of the connection. Any data that has not yet reached its destination may be lost. If the conversation is part of a transaction, the transaction must be rolled back.

- Can only be called by the initiator of the conversation.

6.8 Understanding Conversational Communication Events

Oracle WebLogic Tuxedo Connector JATMI uses five events to manage conversational communication. The following table lists the events, the functions for which they are returned, and a detailed description of each.

Table 6-5 Oracle WebLogic Tuxedo Connector Conversational Communication Events

Event

Received by

Description

TPEV_SENDONLY

Tuxedo tprecv

Control of the connection has passed; this Oracle Tuxedo process can now call tpsend

TPEV_SENDONLY

JATMI tprecv

Control of the connection has passed; this JATMI process can now call tpsend

TPEV_DISCONIMM

Tuxedo tprecv, tpsend, tpreturn

The connection has been torn down and no further communication is possible. The JATMI tpdiscon posts this event in the originator of the connection. The originator sends it to all open connections when tpreturn is called. Connections are closed in a disorderly manner and if a transaction exists, it is aborted.

TPEV_DISCONIMM

JATMI tprecv, tpsend, return

The connection has been torn down and no further communication is possible. The Oracle Tuxedo tpdiscon posts this event in the originator of the connection. The originator sends it to all open connections when return is called. Connections are closed in a disorderly manner and if a transaction exists, it is aborted.

TPEV_SVCERR

Tuxedo tpsend or JATMI tpsend

Received by the originator of the connection indicating that the subordinate program issued a tpreturn (Oracle Tuxedo) or return (JATMI) and ended without control of the connection.

TPEV_SVCERR

Tuxedo tprecv or JATMI tprecv

Received by the originator of the connection indicating that the subordinate program issued a successful tpreturn (Oracle Tuxedo) or a successful return (JATMI) without control of the connection, but an error occurred before the call completed.

TPEV_SVCSUCC

Tuxedo tprecv

Received by the originator of the connection, indicating that the subordinate service finished successfully; that is, return was successfully called.

TPEV_SVCSUCC

JATMI tprecv

Received by the originator of the connection, indicating that the subordinate service finished successfully; that is, tpreturn was called with TPSUCCESS.

TPEV_SVCFAIL

Tuxedo tpsend or JATMI tpsend

Received by the originator of the connection indicating that the subordinate program issued a tpreturn (Oracle Tuxedo) or return (JATMI) and ended without control of the connection. The service completed with status of TPFAIL or TPEXIT and the data is set to null.

TPEV_SVCFAIL

Tuxedo tprecv or JATMI tprecv

Received by the originator of the connection indicating that the subordinate program finished unsuccessfully. The service completed with status of TPFAIL or TPEXIT.

6.9 Oracle WebLogic Tuxedo Connector Conversation Guidelines

Use the following guidelines while in conversation mode to insure successful completion of a conversation:

- Use the JATMI conversational primitives as defined in the Oracle WebLogic Tuxedo Connector Conversation interface and ApplicationToMonitorInterface interface.

- Always use a flag.

- Only use flags defined in the Oracle WebLogic Tuxedo Connector JATMI.

- Oracle WebLogic Tuxedo Connector does not have a parameter that can be used to limit the number of simultaneous conversations to prevent overloading the Oracle WebLogic Server network.

- If Oracle Tuxedo exceeds the maximum number of possible conversations (defined by the MAXCONV parameter), TPEV_DISCONIMM is the expected Oracle WebLogic Tuxedo Connector exception value.

- A tprecv to an unauthorized Oracle Tuxedo service results in a TPEV_DISCONIMM exception value.

- If a Oracle WebLogic Tuxedo Connector client is connected to an Oracle Tuxedo conversational service which does tpforward to another conversational service, TPEV_DISCONIMM is the expected Oracle WebLogic Tuxedo Connector exception value.

- Conversations may be initiated within a transaction. Start the conversation as part of the program statements in transaction mode. For more information on transactions, see Oracle WebLogic Tuxedo Connector JATMI Transactions.

- If an Oracle WebLogic Tuxedo Connector remote domain experiences a TPENOENT, the remote domain will send back a disconnect event message and be caught on the Oracle WebLogic Tuxedo Connector application tprecv as a TPEV_DISCONIMM exception.

7 Using FML with Oracle WebLogic Tuxedo Connector

This chapter describes how Oracle WebLogic Tuxedo Connector uses the Field Manipulation Language (FML).

This chapter includes the following sections:

- Overview of FML

- The Oracle WebLogic Tuxedo Connector FML API

- FML Field Table Administration

- tBridge XML/FML32 Translation

- Using the XmlFmlCnv Class for XML to and From FML/FML32 Translation

- MBSTRING Usage

7.1 Overview of FML

Note:

For more information about using FML, see Programming a Tuxedo ATMI Application Using FML at http://docs.oracle.com/cd/E13203_01/tuxedo/tux100/fml/fml01.html.

FML is a set of java language functions for defining and manipulating storage structures called fielded buffers. Each fielded buffer contains attribute-value pairs in fields. For each field:

- The attribute is the field's identifier.

- The associated value represents the field's data content.

- An occurrence number.

There are two types of FML:

- FML16 based on 16-bit values for field lengths and identifiers. It is limited to 8191 unique fields, individual field lengths of 64K bytes, and a total fielded buffer size of 64K bytes.

- FML32 based on 32-bit values for the field lengths and identifiers. It allows for about 30 million fields, and field and buffer lengths of about 2 billion bytes.

7.2 The Oracle WebLogic Tuxedo Connector FML API

Note:

The Oracle WebLogic Tuxedo Connector implements a subset of FML functionality. For more information regarding FML32, refer to FML32 Considerations.

The FML application program interface (API) is documented in the weblogic.wtc.jatmi package included in the Javadocs for WebLogic Server Classes.

7.3 FML Field Table Administration

Field tables are generated in a manner similar to Oracle Tuxedo field tables. The field tables are text files that provide the field name definitions, field types, and identification numbers that are common between the two systems. To interoperate with an Oracle Tuxedo system using FML, the following steps are required:

1. Copy the field tables from the Oracle Tuxedo system to Oracle WebLogic Tuxedo Connector environment.

For example: Your Oracle Tuxedo distribution contains a bank application example called bankapp. It contains a file called bankflds that has the following structure:

#Copyright (c) 1990 Unix System Laboratories, Inc.
#All rights reserved
#ident  "@(#) apps/bankapp/bankflds     $Revision: 1.3 $"
# Fields for database bankdb
# name                         number  type    flags   comments
ACCOUNT_ID                     110     long    -       -
ACCT_TYPE                      112     char    -       -
ADDRESS                        109     string  -       -
.
.
.

2. Converted the field table definition into Java source files. Use the mkfldclass utility supplied in the weblogic.wtc.jatmi package. This class is a utility function that reads a FML32 Field Table and produces a Java file which implements the FldTbl interface. There are two instances of this utility:

- mkfldclass

- mkfldclass32

Use the correct instance of the command to convert the bankflds field table into FML32 java source. The following example uses mkfldclass.

java weblogic.wtc.jatmi.mkfldclass bankflds

The resulting file is called bankflds.java and has the following structure:

import java.io.*;
import java.lang.*;
import java.util.*;
import weblogic.wtc.jatmi.*;

public final class bankflds
implements weblogic.wtc.jatmi.FldTbl
{
/** number: 110  type: long */
public final static int ACCOUNT_ID = 33554542;
/** number: 112  type: char */
public final static int ACCT_TYPE = 67108976;
/** number: 109  type: string */
public final static int ADDRESS = 167772269;
/** number: 117  type: float */
.
.
.

3. Compile the resulting bankflds.java file using the following command:

javac bankflds.java

The result is a bankflds.class file. When loaded, the Oracle WebLogic Tuxedo Connector uses the class file to add, retrieve and delete field entries from an FML32 field.

4. Add the field table class file to your application CLASSPATH.

5. Update your WTCServer MBean.

- Update the WTCResources MBean to reflect the fully qualified location of the field table class file.

- Use the keywords required to describe the FML buffer type: fml16 or fml32.

- You can enter multiple field table classes in a comma separated list.

For example:

<wtc-resources>
<name>BankappResources</name>
<fld-tbl16-class>my.bankflds</fld-tbl16-class>
<fld-tbl16-class>your.bankflds</fld-tbl16-class>
<fld-tbl16-class>more.bankflds</fld-tbl16-class>
</wtc-resources>

6. Restart your Oracle WebLogic Server to load the field table class definitions.

7.3.1 Using the DynRdHdr Property for mkfldclass32 Class

Oracle WebLogic Tuxedo Connector provides a property that provides an alternate method to compile FML tables. You may need to use the DynRdHdr utility if:

- You are using very large FML tables and the .java method created by the mkfldclass32 class exceeds the internal Java Virtual Machine limit on the total complexity of a single class or interface.

- You are using very large FML tables and are unable to load the class created when compiling the .java method.

Use the following steps to use the DynRdHdr property when compiling your FML tables:

1. Convert the field table definition into Java source files.

java -DDynRdHdr=Path_to_Your_FML_Table weblogic.wtc.jatmi.mkfldclass32 userTable

The arguments for this command are defined as follows:

Attribute

Description

-DDynRdHdr

Oracle WebLogic Tuxedo Connector property used to compile an FML table.

Path_to_Your_FML_Table

Path name of your FML table. This may be either a fully qualified path or a relative path that can be found as a resource file using the server's CLASSPATH.

weblogic.wtc.jatmi.mkfldclass32

This class is a utility function that reads an FML32 Field Table and produces a Java file which implements the FldTbl interface.

userTable

Name of the .java method created by the mkfldclass32 class.

2. Compile the userTable file using the following command:

javac userTable.java

3. Add the userTable.class file to your application CLASSPATH.

4. Update the WTCResources MBean to reflect the fully qualified location of the userTable.class file.

5. Target your WTC server. The userTable.class is loaded when the WTCServer service starts.

Once you have created the userTable.class file, you can modify the FML table and deploy the changes without having to manually create an updated userTable.class. When the WTC server is started, Oracle WebLogic Tuxedo Connector will load the updated FML table using the location specified in the Resources tab of your WTC server configuration. If the Path_to_Your_FML_Table attribute changes, you will need to use the preceding procedure to update your userTable.java and userTable.class files.

7.4 Using TypedFML32 Constructors

Two new constructors for TypedFML32 are available to improve performance. The following topic provides explanation as to when to use these constructors.

The constructors are defined in the Javadocs for WebLogic Server Classes.

7.4.1 Gaining TypedFML32 Performance Improvements

To gain TypedFML32 performance improvements, you can choose to give size hints to TypedFML32 constructors. There are two parameters that are available to those constructor:

- A parameter that hints for maximum number of fields. This includes all the occurrences.

- A parameter for the total number of field IDs used in the buffer.

For instance, a field table used by the buffer contains 20 field IDs, and each field can occur 20 times. In this case, the first parameter should be 400 for the maximum number of fields. The second parameter should be 20 for the total number of field IDs.

TypeFML32 mybuffer = new TypeFML32(400, 20);

Note:

This usually works well with any size of buffer; however, it does not work well with extremely small buffers.

If you have an extremely small buffer, use those constructor without hints. An example of an extremely small buffer is a buffer with less than 16 total occurrences. If the buffer is extremely large, for example contains more than 250000 total field occurrences, then the application should consider splitting it into several buffers smaller than 250000 total field occurrences.

7.5 tBridge XML/FML32 Translation

Note:

The data type specified must be FLAT or NO. If any other data type is specified, the redirection fails.

The TranslateFML element of the WTCtBridgeRedirect MBean is used to indicate if FML32 translation is performed on the message payload. There are two types of FML32 translation: FLAT and NO.

7.5.1 FLAT

The message payload is translated using the Oracle WebLogic Tuxedo Connector internal FML32/XML translator. Fields are converted field-by-field values without knowledge of the message structure (hierarchy) and repeated grouping.

In order to convert an FML32 buffer to XML, the tBridge pulls each instance of each field in the FML32 buffer, converts it to a string, and places it within a tag consisting of the field name. All of these fields are placed within a tag consisting of the service name. For example, an FML32 buffer consisting of the following fields:

NAME          JOE
ADDRESS       CENTRAL CITY
PRODUCTNAME   BOLT
PRICE         1.95
PRODUCTNAME   SCREW
PRICE         2.50

The resulting XML buffer would be:

<FML32>
<NAME>JOE</NAME>
<ADDRESS>CENTRAL CITY</ADDRESS>
<PRODUCTNAME>BOLT</PRODUCTNAME>
<PRODUCTNAME>SCREW</PRODUCTNAME>
<PRICE>1.95</PRICE>
<PRICE>2.50</PRICE>
</FML32>

7.5.2 NO

No translation is used.

For JMS to Oracle Tuxedo, the tBridge maps a JMS TextMessage into an Oracle Tuxedo TypedBuffer (TypedString) and vice versa depending on the direction of the redirection. JMS BytesMessage are mapped into Oracle Tuxedo TypedBuffer (TypedCarray) and vice versa.

For Oracle Tuxedo to JMS, passing an FML/FML32 buffer behaves as if translateFML is set to FLAT. Therefore, in this case, setting translateFML to NO has no effect and if the Oracle Tuxedo buffer is of type FML/FML32, the translation takes place automatically.

7.5.3 FML32 Considerations

Remember to consider the following information when working with FML32:

- For XML input, the root element is required but ignored.

- For XML output, the root element is always <FML32>.

- The field table names must be loaded as described in FML Field Table Administration.

- The tBridge translator is capable of only "flat" or linear grouping. This means that information describing FML32 ordering is not maintained, therefore buffers that contain a series of repeating data could be presented in an unexpected fashion. For example, consider a FML32 buffer that contains a list of parts and their associated price. The expectation would be PART A, PRICE A, PART B, PRICE B, etc. however since there is no structural group information contained within the tBridge, the resulting XML could be PART A, PART B, etc., PRICE A, PRICE B, etc.

- When translating XML into FML32, the translator ignores STRING values. For example, <STRING></STRING> is skipped in the resulting FML32 buffer. All other types cause WTC to log an error resulting in translation failure.

- Embedded FML is not supported in this release.

- Embedded VIEW fields within FML32 buffers are supported in this release.

- TypedCArray is supported for FML/FML32 to XML conversion. Select from the following list of supported field types:

- SHORT

- LONG

- CHAR

- FLOAT

- DOUBLE

- STRING

- CARRAY

- INT (FML32)

- DECIMAL (FML32)

- If you need to pass binary data, encode to a field type of your choice and decode the XML on the receiving side.

- If you need to use CARRAY fields in an XML input buffer, you must first encode the content using base64. You must decode the base64 data after it is received and before it is processed by an application.

7.6 Using the XmlFmlCnv Class for XML to and From FML/FML32 Translation

An alternative option to using the tBridge to automatically translate XML buffers to and from FML/FML32 is to use the XmlFmlCnv class which supports ordering, grouping and beautifying functionality. The following code listing is an example that uses the XmlFmlCnv class for conversion to and from XML buffer formats.

import weblogic.wtc.jatmi.TypedFML32;
import weblogic.wtc.jatmi.FldTbl;
import weblogic.wtc.gwt.XmlFmlCnv;

public class xml2fml
{
public static void main(String[] args) {
String xmlDoc = "<XML><MyString>hello</MyString></XML>";
TypedFML32 fmlBuffer = new TypedFML32(new MyFieldTable());
XmlFmlCnv c = new XmlFmlCnv();
fmlBuffer = c.XMLtoFML32(xmlDoc, fmlBuffer.getFieldTables());
String result = c.FML32toXML(fmlBuffer);
System.out.println(result);
}
}

See Class XmlFmlCnv.

7.6.1 Limitations of XmlFmlCnv Class

The FLD_MBSTRING field in FML32 is not supported by the XmlFmlCnv.FML32toXML method in this release.

7.7 MBSTRING Usage

A TypedMBString object can be used almost identically as a TypedString object in a WTC application code. The only difference is that TypedMBString has a codeset encoding name associated to the string data.

This section includes the following topics.

- Sending MBSTRING Data to an Oracle Tuxedo Domain

- Receiving MBSTRING Data from an Oracle Tuxedo Domain

- Using FML with Oracle WebLogic Tuxedo Connector

7.7.1 Sending MBSTRING Data to an Oracle Tuxedo Domain

When an Oracle Tuxedo message that contains an MBSTRING data is sent to another Oracle Tuxedo domain, TypedMBString uses the conversion function of java.lang.String class to convert between Unicode and an external encoding. The TypedMBString has a codeset encoding name associated to the string data.

When a TypedMBString object is created by a WTC application code, the encoding name is set to null. The null value of the encoding name means that the default encoding name is used for Unicode string to byte array conversion while sending the MBSTRING data to a remote domain. By default, the Java's default encoding name for byte array string is used for the default encoding name.You can specify encoding or accept the default encoding. The following order defines the order of precedence for TypedMBString.

1. Specify the encoding name by setMBEncoding() method.

2. Specify the encoding name through the setDefaultMBEncoding() method of weblogic.wtc.jatmi.MBEncoding class.

3. Specify the encoding name through the RemoteMBEncoding attribute of the WTCResourcesMBean.

4. MBENCODINGPROPERTY system property value.

5. Accept the Java default encoding name.

7.7.2 Receiving MBSTRING Data from an Oracle Tuxedo Domain

When an Oracle Tuxedo message that contains an MBSTRING data is received from a remote domain, the following actions take place.

1. WTC determines the encoding of the MBSTRING data by the codeset tcm in the received message.

2. WTC creates a TypedMBString object.
A TypedMBString object can be used almost identically as a TyepdString object in WTC application code. However, the TypedMBString has a codeset encoding name associated to the string data.

3. WTC passes the TypedMBString object to the WTC application code. The application code knows the encoding of the received MBSTRING data by the instance method getMBEncoding().

7.7.3 Using FML with Oracle WebLogic Tuxedo Connector

FLD_MBSTRING is a field type added to TypedFML32. In this case, a TypedMBString object is passed to the TypedFML32 method as the associated object type of FLD_MBSTRING. You can specify the encoding name used for the MBSTRING conversion for a FLD_MBSTRING field.

The following order defines the order of precedence for TypedFML32.

1. Specify the encoding name by setMBEncoding() method of the TypedMBString object for the field.

2. Specify the encoding name by setMBEncoding() method of the TypedFML32 object.

3. Specify the encoding name through the setDefaultMBEncoding() method of weblogic.wtc.jatmi.MBEncoding class.

4. Specify the encoding name through the RemoteMBEncoding attribute of the WTCResourcesMBean.

5. MBENCODINGPROPERTY system property value.

6. Accept the Java default encoding name.

Note:

The following methods must be updated when using FLD_MBSTRING: Fldtype(), Fchg(), Fadd(), Fget(), and Fdel().

The on-demand encoding methods and auto-conversion methods needed in Oracle Tuxedo, such as Fmbpack32() and Fmbunpack32() are not needed by Oracle WebLogic Tuxedo Connector.

8 Oracle WebLogic Tuxedo Connector JATMI VIEWs

This chapter describes how to use Oracle WebLogic Tuxedo Connector VIEW buffers.

This chapter includes the following sections:

- Overview of Oracle WebLogic Tuxedo Connector VIEW Buffers

- How to Create a VIEW Description File

- How to Use the viewj Compiler

- How to Pass Information to and from a VIEW Buffer

- How to Use VIEW Buffers in JATMI Applications

- Using the XmlViewCnv Class for XML to and From View/View(32) Translation

8.1 Overview of Oracle WebLogic Tuxedo Connector VIEW Buffers

Note:

For more information on Oracle Tuxedo VIEW buffers, see Using a VIEW Typed Buffer in Programming a Tuxedo ATMI Application Using C at http://docs.oracle.com/cd/E13203_01/tuxedo/tux100/pgc/pgbuf.html.

Oracle WebLogic Tuxedo Connector allows you to create a Java VIEW buffer type analogous to an Oracle Tuxedo VIEW buffer type derived from an independent C structure. This allows Oracle WebLogic Server applications and Oracle Tuxedo applications to pass information using a common structure. Oracle WebLogic Tuxedo Connector VIEW buffers do not support FML VIEWs or FML VIEWs/Java conversions.

8.2 How to Create a VIEW Description File

Note:

fbname and null fields are not relevant for independent Java and C structures and are ignored by the Java and C VIEW compiler. You must include a value (for example, a dash) as a placeholder in these fields.

Your Oracle WebLogic Server application and your Oracle Tuxedo application must share the same information structure as defined by the VIEW description. The following format is used for each structure in the VIEW description file:

$ /* VIEW structure */
VIEW viewname
type cname fbname count flag size null

where

- The file name is the same as the VIEW name.

- You can have only one VIEW description per file.

- The VIEW description file is the same file used for both the Oracle WebLogic Tuxedo Connector viewj compiler and the Oracle Tuxedo viewc compiler.

- viewname is the name of the information structure.

- You can include a comment line by prefixing it with the # or $ character.

- The following table describes the fields that must be specified in the VIEW description file for each structure.

Table 8-1 VIEW Description File Fields

Field

Description

type

Data type of the field. Can be set to short, long, float, double, char, string, carray, or dec_t (packed decimal).

cname

Name of the field as it appears in the information structure.

fbname

Ignored.

count

Number of times field occurs.

flag

Specifies any of the following optional flag settings:

- N—zero-way mapping

- C—generate additional field for associated count member (ACM)

- L—hold number of bytes transferred for STRING and CARRAY

size

For STRING and CARRAY buffer types, specifies the maximum length of the value. This field is ignored for all other buffer types.

null

User-specified NULL value, or minus sign (-) to indicate the default value for a field. NULL values are used in VIEW typed buffers to indicate empty C structure members.

The default NULL value for all numeric types is 0 (0.0 for dec_t). For character types, the default NULL value is `\0'. For STRING and CARRAY types, the default NULL value is " ".

Constants used, by convention, as escape characters can also be used to specify a NULL value. The VIEW compiler recognizes the following escape constants: \ddd (where d is an octal digit), \0, \n, \t, \v, \r, \f, \\, \', and \".

You may enclose STRING, CARRAY, and char NULL values in double or single quotes. The VIEW compiler does not accept unescaped quotes within a user-specified NULL value.

You can also specify the keyword NONE in the NULL field of a VIEW member description, which means that there is no NULL value for the member. The maximum size of default values for string and character array members is 2660 characters.

8.2.1 Example VIEW Description File

The following provides an example VIEW description which uses VIEW buffers to send information to and receive information from an Oracle Tuxedo application. The file name for this VIEW is infoenc.

Example 8-1 Example VIEW Description

VIEW infoenc
#type    cname    fbname  count flag size null
float    amount   AMOUNT  2     -    -    0.0
short    status   STATUS  2     -    -    0
int      term     TERM    2     -    -    0
char     mychar   MYCHAR  2     -    -    -
string   name     NAME    1     -    16   -
carray   carray1  CARRAY1 1     -    10   -
dec_t    decimal  DECIMAL 1     -    9    - #size ignored by viewj/viewj32
END

8.3 How to Use the viewj Compiler

To compile a VIEW typed buffer, run the viewj command, specifying the package name and the name of the VIEW description file as arguments. The output file is written to the current directory.

To use the viewj compiler, enter the following command:

java weblogic.wtc.jatmi.viewj [options] [package] viewfile

To use the viewj32 compiler, enter the following command:

java weblogic.wtc.jatmi.viewj32 [options] [package] viewfile

The arguments for this command are defined as follows:

Argument

Description

options

- -associated_fields:
Use to set AssociatedFieldHandling to true. This allows set and get accessor methods to use the values of the associated length and count fields if they are specified in the VIEW description file. If not specified, the default value for AssociatedFieldHandling is false.

- -bean_names:
Use to create set and get accessor names that follow JavaBeans naming conventions. The first character of the field name is changed to upper case before the set or get prefix is added. The signature of indexed set accessors for array fields changes from the default signature of void setAfield(T value, int index) to void setAfield(int index, T value).

- -compat_names:
Use to create set and get accessor names that are formed by taking the field name from the VIEW description file and adding a set or get prefix. Provides compatibility with releases prior to WebLogic Server 8.1 SP2. Default value is -compat_names if -bean_names or -compat_names is not specified.

- -modify_strings:
Use to generate different Java code for encoding strings sent to Oracle Tuxedo and decoding strings received from Oracle Tuxedo. Encoding code adds a null character to the end of each string. Decoding code truncates each string at the first null character received.

- -xcommon:
Use to generate output class as extending TypedXCommon instead of TypedView.

- -xtype:
Use to generate output class as extending TypedXCType instead of TypedView.

Note: -compat_names and -bean_names are mutually exclusive options.

package

The package name to be included in the .java source file.

Example: examples.wtc.atmi.simpview

viewfile

Name of the VIEW description file.

Example: Infoenc

For example:

- A VIEW buffer is compiled as follows:

java weblogic.wtc.jatmi.viewj -compat_names examples.wtc.atmi.simpview infoenc

- A VIEW32 buffer is compiled as follows:

java weblogic.wtc.jatmi.viewj32 -compat_names -modify_strings
examples.wtc.atmi.simpview infoenc

8.4 How to Pass Information to and from a VIEW Buffer

The output of the viewj and viewj32 command is a .java source file that contains set and get accessor methods for each field in the VIEW description file. Use these set and get accessor methods in your Java applications to pass information to and from a VIEW buffer.

The AssociatedFieldHandling flag is used to specify if the set and get methods use the values of the associated length and count fields if they are specified in the VIEW description file.

- set methods set the count for an array field and set the length for a string or carray field.

- Array get methods return an array that is at most the size of the associated count field.

- String and carray get methods return data that is at most the length of the associated length field.

Use one of the following to set or get the state of the AssociatedFieldHandling flag:

- Use the -associated_fields option for the viewj and viewj32 compiler to set the AssociatedFieldHandling flag to true.

- Invoke the void setAssociatedFieldHandling(boolean state) method in your Java application to set the state of the AssociatedFieldHandling flag.

- If false, the set and get methods ignore the length and count fields.

- If true, the set and get methods use the values of the associated length and count fields if they are specified in the VIEW description file.

- The default state is false.

- Invoke the boolean getAssociatedFieldHandling() method in your Java application to return the current state of AssociatedFieldHandling.

8.5 How to Use VIEW Buffers in JATMI Applications

Use the following steps when incorporating VIEW buffers in your JATMI applications:

1. Create a VIEW description file for your application as described in How to Create a VIEW Description File.

2. Compile the VIEW description file as described in How to Use the viewj Compiler.

3. Use the set and get accessor methods to pass information to and receive information from a VIEW buffer as described in How to Pass Information to and from a VIEW Buffer.

See the examples/wtc/atmi/simpview/ViewClient.java file in your Oracle WebLogic Server distribution for an example of how a client uses accessors to pass information to and from a VIEW buffer.

Please note that for this release, WTC samples are available on the BEA dev2dev website in the Code Library.

4. Import the output of the VIEW compiler into your source code.

5. If necessary, compile the VIEW description file for your Oracle Tuxedo application and include the output in your C source file as described in Using a VIEW Typed Buffer in Programming a Tuxedo ATMI Application Using C at http://docs.oracle.com/cd/E13203_01/tuxedo/tux100/pgc/pgbuf.html.

6. Configure a WTCServer MBean with a Resources Mbean that specifies the VIEW buffer type (VIEW or VIEW32) and the fully qualified class name of the compiled Java VIEW description file. The class of the compiled Java VIEW description file should be in your CLASSPATH.

7. Build and launch your Oracle Tuxedo application.

8. Build and launch your Oracle WebLogic Server Application.

8.5.1 How to Get VIEW32 Data In and Out of FML32 Buffers

A helper class is available to add and get VIEW32 data in and out of an FML32 buffer. The class name is wtc.jatmi.FViewFld. This class assists programmers in developing JATMI-based applications that use VIEW32 field type for FML32 buffers.

No change to configuration is required. You still configure the VIEW32 class path using the ViewTbl32Classes attribute in the WTCResources section of the WLS configuration file.

The following access methods are available in this helper class.

- FViewFld(String vname, TypedView32 vdata);

- FviewFld(FviewFld to_b_clone);

- void setViewName(String vname)

- String getViewName();

- void setViewData(TypedView32 vdata)

- void TypedView32 getViewData();

Example 8-2 How to Add and Retrieve an Embedded TypedView32 buffer in a TypedFML32 Buffer

String toConvert = new String("hello world");
TypedFML32 MyData = new TypedFML32(new MyFieldTable());
Long d1 = new Long(1234);
Float d2 = new Float(12.32);
MyView data = new myView();
FviewFld vfld;
data.setamount((float)100.96);
data.setstatus((short)3);
vfld = new FviewFld("myView", data);

try {
myData.Fchg(MyFieldTable.FLD0, 0, toConvert);
myData.Fchg(MyFieldTable.FLD1, 0, 1234);
myData.Fchg(MyFieldTable.FLD2, 0, d2);
myData.Fchg(MyFieldTable.myview, 0, vfld);
} catch (Ferror fe) {
log("An error occurred putting data into the FML32 buffer.  The error is " + fe);
}

try {
myRtn = myTux.tpcall("FMLVIEW", myData, 0);
} catch(TPReplyException tre) {
….
}
TypedFML32  myDataBack = (TypedFML32)myRtn.getReplyBuffer();
Integer myNewLong;
Float myNewFloat;
myView View;
String myNewString;

try {
myNewString = (String)myDataBack.Fget(MyFieldTable.FLD0, 0);
myNewLong = (Integer)myDataBack.Fget(MyFieldTable.FLD1, 0);
myNewFloat = (Float)myDataBack.Fget(MyFieldTable.FLD2, 0);
vfld = (FviewFld)myDataBack.Fget(MyFieldTable.myview, 0);
view = (myView)vfld.getViewData();
} catch (Ferror fe) {
….
}

The following code listing is an example FML Description(MyFieldTable) related to the example in Example 8-2.

*base 20000
#name    number  type   flags   comments
FLD0     10      string -       -
FLD1     20      long   -       -
FLD2     30      float  -       -
myview   50      view32 -       defined in View description file

8.6 Using the XmlViewCnv Class for XML to and From View/View(32) Translation

Use the XmlViewCnv class to perform XML to View /View(32) or View/View(32) to XML translation. The following code listing is an example that uses the XmlViewCnv class for conversion to and from XML buffer formats.

import examples.wtc.atmi.simpview.infoenc; // View class import
weblogic.wtc.gwt.XmlViewCnv;
import weblogic.wtc.jatmi.TypedBuffer;

public class xml2view
{
public static void main(String[] args) {
String xmlDoc =
"<VIEW32><infoenc><amount>1000.0</amount><infoenc></VIEW32>";

infoenc convertMe = new infoenc();
convertMe = (infoenc) XmlViewCnv.XMLToView(
xmlDoc,
convertMe.getClass(),
convertMe.getSubtype());

convertMe = (infoenc) echo.Echo(convertMe);

result = XmlViewCnv.ViewToXML(
(TypedBuffer) convertMe,
convertMe.getClass(),
true);

System.out.println(result);
}
}

8.6.1 Translating Nested Views

Nested views are views which contains one or more members of type struct, which are themselves a view. This section provides an example of converting a nested view to XML.

The following is a nested view file:

VIEW file
VIEW    MYVIEW1
#type   Cname   Fbname  Count   Flag    Size    null
long    long1   -       1       -       -       0
string  string1 -       1       -       20      '\0`
END

VIEW    MYVIEW2
#type   Cname   Fbname  Count   Flag    Size    null
long    long1   -       1       -       -       0
bool    bool1   -       1       -       -       0
signedchar      schar1   -       1       -       -       0
struct  MYVIEW1 myview1 2       -       -       NONE
END

The translated XML string is:

<VIEW32>
<MYVIEW2>
<bool1>true</bool1>
<long1>100</long1>
<myview1><VIEW32><MYVIEW1>
<string1>aa11</string1>
<long1>100</long1>
</MYVIEW1></VIEW32></myview1>
<myview1><VIEW32><MYVIEW1>
<string1>bb22</string1>
<long1>100</long1>
</MYVIEW1></VIEW32></myview1>
<schar1>100</schar1>
</MYVIEW2>
</VIEW32>

9 How to Create a Custom AppKey Plug-in

This chapter describes how to create custom AppKey generator plug-ins.

This chapter includes the following sections:

- How to Create a Custom Plug-In

- Example Custom Plug-in

9.1 How to Create a Custom Plug-In

Note:

You cannot customize Oracle Tuxedo AAA tokens.

1. Create your custom Java plug-in using the AppKey and UserRec interfaces. You can provide any required initialization parameters or a property file using the param parameter of the init method.

2. Compile your plug-in. Example:

javac exampleAppKey.java

3. Update your CLASSPATH to include the path to your compiled plug-in. Example:

export CLASSPATH=$CLASSPATH:/home/mywork

4. Start your server.

5. Configure your WTC server to use the Custom Plug-in. For more information, see the Custom Plug-in in Administering WebLogic Tuxedo Connector for Oracle WebLogic Server.

9.2 Example Custom Plug-in

The exampleAppKey.java file is an example of a custom plug-in. It utilizes a tpusrfile file as the database to store the AppKey.

Example 9-1 exampleAppKey.Java Custom Plug-In

import java.io.*;
import java.lang.*;
import java.util.*;
import java.security.Principal;
import weblogic.wtc.jatmi.AppKey;
import weblogic.wtc.jatmi.UserRec;
import weblogic.wtc.jatmi.DefaultUserRec;
import weblogic.wtc.jatmi.TPException;
import weblogic.security.acl.internal.AuthenticatedSubject;
import weblogic.security.WLSPrincipals;

/**
* @author Copyright (c) 2002 by BEA Systems, Inc. All Rights Reserved.
*/

/**
* @exclude
* Sample AppKey plug-in using TPUSRFILE as the database for APPKEY.
* It is installed through "Custom" option.
* The syntax for option custom plug parameter input contains the full
* pathname to the <tpusrfile>
*
* @author BEA Systems, Inc.
*/
public class exampleAppKey implements AppKey {
private String  anon_user = null;
private String  tpusrfile = null;
private File    myfile;
private HashMap userMap;
private long    l_time;
private int     dfltAppkey;
private boolean allowAnon;
private final static int USRIDX = 0;
private final static int PWDIDX = 1;
private final static int UIDIDX = 2;
private final static int GIDIDX = 3;
private final static int CLTIDX = 4;

private final static byte[] tpsysadm_string = {
(byte)'t', (byte)'p', (byte)'s', (byte)'y', (byte)'s',
(byte)'a', (byte)'d', (byte)'m' };
private final static byte[] tpsysop_string = {
(byte)'t', (byte)'p', (byte)'s', (byte)'y', (byte)'s', (byte)'o',
(byte)'p' };

public void init(String param, boolean anonAllowed, int dfltAppKey)
throws TPException {

if (param == null) {
System.out.println("Error: tpusrAppKey.init@param == null");
throw new TPException(TPException.TPESYSTEM,
"Invalid input parameter");
}

// get the tpusrfile name
parseParam(param);

myfile  = new File(tpusrfile);
if (myfile.exists() != true) {
System.out.println("Error: exampleAppKey.init@file \"" + param
+ "\" does not exist");
throw new TPException(TPException.TPESYSTEM,
"Failed to find TPUSR file");
}
if (myfile.isFile() != true) {
System.out.println("Error: exampleAppKey.init@the specified name \"" +
param + "\" is not a file");
throw new TPException(TPException.TPESYSTEM,
"Invalid TPUSR file");
}
if (myfile.canRead() != true) {
System.out.println("Error: exampleAppKey.init@file \"" + param +
"\" is not readable");
throw new TPException(TPException.TPESYSTEM,
"Bad TPUSR file permission");
}

userMap = new HashMap();

// create the cache
if (createCache(tpusrfile) == -1) {
System.out.println("Error: exampleAppkey.init@fail to create user cache");
throw new TPException(TPException.TPESYSTEM,
"fail to create user cache");
}

l_time     = myfile.lastModified();
anon_user  = weblogic.security.WLSPrincipals.getAnonymousUsername();
allowAnon  = anonAllowed;
dfltAppkey = dfltAppKey;

System.out.println("exampleAppKey installed!");

return;
}

public void uninit() throws TPException {
if (userMap != null) {
userMap.clear();
}
return;
}

public UserRec getTuxedoUserRecord(AuthenticatedSubject subj) {
Object[] obj = subj.getPrincipals().toArray();
if (obj == null || obj.length == 0) {
// a subject without principals is an anonymous user
if (allowAnon) {
return new DefaultUserRec(anon_user, dfltAppkey);
}
System.out.println("Error: exampleAppKey.
getTuxedoUserRecord@return " +
"anonymous user not allowed");
return null;
}

// looping through all Principal names if necessary to get first user
// name defined in tpuser file
Principal user;
String    username;
int       key;
UserRec   rec;

for (int i = 0; i < obj.length; i++) {
user     = (Principal)obj[i];
username = user.getName();
if (username.equals(anon_user)) {
return new DefaultUserRec(anon_user, dfltAppkey);
}
if ((rec = (UserRec)userMap.get(username)) != null) {
return rec;
}
}
System.out.println("WARN: exampleAppKey.getTuxedoUserRecord@return " +
"null UserRec");
return null;
}

private int createCache(String fname) {
FileInputStream fin;
byte[]          line;

try {
fin = new FileInputStream(fname);

while ((line = readOneLine(fin)) != null) {
DefaultUserRec newUser = parseOneLine(line);
if (newUser != null) {
userMap.put(newUser.getRemoteUserName(), newUser);
}
}
fin.close();
}
catch (FileNotFoundException fnfe) {
System.out.println("Error: exampleAppKey.createCache@reason: " + fnfe);
return -1;
}
catch (SecurityException se) {
System.out.println("Error: exampleAppKey.createCache@reason: " + se);
return -1;
}
catch (IOException ioe) {
System.out.println("Error: exampleAppKey.createCache@reason: " + ioe);
return -1;
}
catch (Exception e) {
System.out.println("Error: exampleAppKey.createCache@reason: " + e);
return -1;
}
return 0;
}

private byte[] readOneLine(FileInputStream fh) {
int    len  = 80;
byte[] line = new byte[len];
int    inp  = -1;
int    idx  = 0;

try {
while ((inp = fh.read()) != -1) {
if (idx == 0 && (inp == '\n' || inp == '\0')) {
continue;
}
if (inp == '\n') {
break;
}
if (idx == (len - 1)) {
byte[] tmp = new byte[len + 80];
System.arraycopy(line, 0, tmp, 0, len);
line = tmp;
len += 80;
}
line[idx] = (byte)inp;
idx++;
}
}
catch (Exception e) {
System.out.println("Error: exampleAppKey.readOneLine@reason: " + e);
return null;
}

if (inp == -1 && idx == 0) {
return null;
}

byte[] tmp = new byte[idx];
System.arraycopy(line, 0, tmp, 0, idx);

return tmp;
}

private DefaultUserRec parseOneLine(byte[] line) {
String      name;
int         key   = 0;
DefaultUserRec usr;
int         firstCharacter;
int         i;
int         sidx;
int         fldlen;
int         fn;
byte[]      buid  = null;
byte[]      bgid  = null;
byte[]      clt   = null;
byte[]      uname = null;

firstCharacter = (int)line[0];
if (firstCharacter == '#' || firstCharacter == '\n' ||
firstCharacter == '!' || firstCharacter == '\0' ||
firstCharacter == '\r') {
return null;
}
fldlen = 0;
sidx   = 0;
for (i = 0, fn = 0; i < line.length && fn <= CLTIDX; i++) {
if (line[i] == (byte)':') {
switch (fn) {
case USRIDX:
uname = new byte[fldlen];
System.arraycopy(line, sidx, uname, 0, fldlen);
break;
case UIDIDX:
buid = new byte[fldlen];
System.arraycopy(line, sidx, buid, 0, fldlen);
break;
case GIDIDX:
bgid = new byte[fldlen];
System.arraycopy(line, sidx, bgid, 0, fldlen);
break;
case CLTIDX:
if (line[sidx  ] == (byte)'T' &&
line[sidx+1] == (byte)'P' &&
line[sidx+2] == (byte)'C' &&
line[sidx+3] == (byte)'L' &&
line[sidx+4] == (byte)'T' &&
line[sidx+5] == (byte)'N' &&
line[sidx+6] == (byte)'M' &&
line[sidx+7] == (byte)',') {
sidx   += 8;
fldlen -= 8;
}
if (fldlen > 0) {
clt = new byte[fldlen];
System.arraycopy(line, sidx, clt, 0, fldlen);
}
break;
default:
break;
}   // end of switch
fn++;
fldlen = 0;
sidx   = i + 1;
}     // end of if
else {
fldlen++;
}
}

// try to tolerate incomplete line
if (fn <= CLTIDX && fldlen > 0) {
switch (fn) {
case USRIDX:
uname = new byte[fldlen];
System.arraycopy(line, sidx, uname, 0, fldlen);
break;
case UIDIDX:
buid = new byte[fldlen];
System.arraycopy(line, sidx, buid, 0, fldlen);
break;
case GIDIDX:
bgid = new byte[fldlen];
System.arraycopy(line, sidx, bgid, 0, fldlen);
break;
case CLTIDX:
if (line[sidx  ] == (byte)'T' &&
line[sidx+1] == (byte)'P' &&
line[sidx+2] == (byte)'C' &&
line[sidx+3] == (byte)'L' &&
line[sidx+4] == (byte)'T' &&
line[sidx+5] == (byte)'N' &&
line[sidx+6] == (byte)'M' &&
line[sidx+7] == (byte)',') {
sidx   += 8;
fldlen -= 8;
}
clt = new byte[fldlen];
System.arraycopy(line, sidx, clt, 0, fldlen);
break;
}
}

if (uname == null || buid == null || bgid == null) {
return null;
}

name = new String(uname);
if (clt != null) {
if (Arrays.equals(tpsysadm_string, clt) == true) {
key = TPSYSADM_KEY;
}
else if (Arrays.equals(tpsysop_string, clt) == true) {
key = TPSYSOP_KEY;
}
}

if (key == 0) {
Integer u_val;
Integer g_val;
int uid = 0;
int gid = 0;

try {
u_val = new Integer(new String(buid));
g_val = new Integer(new String(bgid));
uid   = u_val.intValue();
gid   = g_val.intValue();
uid &= UIDMASK;
gid &= GIDMASK;
key = uid | (gid << GIDSHIFT);
}
catch (NumberFormatException nfe) {
System.out.println("Error: exampleAppKey.readOneLine@reason: " + nfe);
return null;
}
}

return new DefaultUserRec(name, key);
}

private void parseParam(String param) {
String str;

// trim the input
tpusrfile = param.trim();

return;
}
}

10 Application Error Management

This chapter describes mechanisms used to manage and interpret error conditions in your applications that occur when using Oracle WebLogic Tuxedo Connector.

This chapter includes the following sections:

- Testing for Application Errors

- Oracle WebLogic Tuxedo Connector Time-Out Conditions

- Guidelines for Tracking Application Events

10.1 Testing for Application Errors

Note:

To view an example that demonstrates how to test for error conditions, see Example Transaction Code.

Your application logic should test for error conditions after the calls that have return values and take suitable steps based on those conditions. In the event that a function returned a value, you may invoke a functions that tests for specific values and performs the appropriate application logic for each condition.

10.1.1 Exception Classes

The Oracle WebLogic Tuxedo Connector throws the following exception classes:

- Ferror: Exception thrown for errors occurring while manipulating FML.

- TPException: Exception thrown that represents a TPException failure.

- TPReplyException: Exception thrown that represents a TPException failure when user data is associated with the exception thrown.

10.1.2 Fatal Transaction Errors

In managing transactions, it is important to understand which errors prove fatal to transactions. When these errors are encountered, transactions should be explicitly aborted on the application level by having the initiator of the transaction call commit(). Transactions fail for the following reasons:

- The initiator or participant of the transaction caused it to be marked for rollback.

- The transaction timed out.

- A commit() was called by a participant rather than by the originator of a transaction.

10.2 Oracle WebLogic Tuxedo Connector Time-Out Conditions

There are two types of time-out which can occur when using the Oracle WebLogic Tuxedo Connector:

- Blocking time-out.

- Transaction time-out.

10.2.1 Blocking vs. Transaction Time-out

Blocking time-out is exceeding the amount of time a call can wait for a blocking condition to clear up. Transaction time-out occurs when a transaction takes longer than the amount of timed defined for it in setTransactionTimeout(). By default, if a process is not in transaction mode, blocking time-outs are performed. When the flags parameter of a a communication call is set to TPNOTIME, it applies to blocking time-outs only. If a process is in transaction mode, blocking time-out and the TPNOTIME flag are not relevant. The process is sensitive to transaction time-out only as it has been defined for it when the transaction was started. The implications of the two different types of time-out follow:

- If a process is not in transaction mode and a blocking time-out occurs on an asynchronous call, the communication call that blocked will fail, but the call descriptor is still valid and may be used on a re-issue call. Further communication in general is unaffected.

- In the case of transaction time-out, the call descriptor to an asynchronous transaction reply (done without the TPNOTRAN flag) becomes stale and may no longer be referenced. The only further communication allowed is the one case described earlier of no reply, no blocking, and no transaction.

10.2.2 Effect on commit()

The state of a transaction if time-out occurs after the call to commit() is undetermined. If the transaction timed out and the system knows that it was aborted, setRollbackOnly() or rollback() returns with an error.

If the state of the transaction is in doubt, you must query the resource to determine if any of the changes that were part of that transaction have been applied to it in order to discover whether the transaction committed or aborted.

10.2.3 Effect of TPNOTRAN

Note:

A transaction can time-out while waiting for a reply that is due from a service that is not part of that transaction.

When a process is in transaction and makes a communications call with flags set to TPNOTRAN, it prohibits the called service from becoming a participant of that transaction. The success or failure of the service does not influence the outcome of that transaction.

10.3 Guidelines for Tracking Application Events

You can track the execution of your applications by using System.out.println() to write messages to the Oracle WebLogic Server trace log. Create a log() method that takes a variable of type String and use the variable name as the argument to the call, or include the message as a literal within quotation marks as the argument to the call. In the following example, a series of messages are used to track the progress of a tpcall().

Example 10-1 Example Event Logging

.
.
.
log("About to call tpcall");
try {
myRtn = myTux.tpcall("TOUPPER", myData, 0);
}
catch (TPReplyException tre) {
log("tpcall threw TPReplyExcption " + tre);
throw tre;
}
catch (TPException te) {
log("tpcall threw TPException " + te);
throw te;
}
catch (Exception ee) {
log("tpcall threw exception: " + ee);
throw new TPException(TPException.TPESYSTEM, "Exception: " + ee);
}
log("tpcall successfull!");
.
.
.
private static void
log(String s)
{System.out.println(s);}
.
.
.

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