Workflow Service Clients

Any worklist application accesses the various workflow services through the workflow service client. The workflow service client code encapsulates all the logic required for communicating with the workflow services using different local and remote protocols. After the worklist application has an instance of the workflow service client, it does not need to consider how the client communicates with the workflow services.

The advantages of using the client are as follows:

Hides the complexity of the underlying connection mechanisms such as SOAP/HTTP and Enterprise JavaBeans
Facilitates changing from using one particular invocation mechanism to another, for example from SOAP/HTTP to remote Enterprise JavaBeans

The following class is used to create instances of the IWorkflowServiceClient interface:

oracle.bpel.services.workflow.client.WorkflowServiceClientFactory

WorkflowServiceClientFactory has several methods that create workflow clients. The simplest method, getWorkflowServiceClient, takes a single parameter, the client type. The client type can be one of the following:

WorkflowServiceClientFactory.REMOTE_CLIENT—The client uses a remote Enterprise JavaBeans interface to invoke workflow services located remotely from the client.
WorkflowServiceClientFactory.SOAP_CLIENT—The client uses SOAP to invoke web service interfaces to the workflow services, located remotely from the client.

The other factory methods enable you to specify the connection properties directly (rather than having the factory load them from the wf_client_config.xml file), and enable you to specify a logger to log client activity.

The following enhancements to the workflow service clients are included in this release:

You can specify the workflow client configuration using either a JAXB object or a map, as shown in example 1 and 2 below:

Example 1

WorkflowServicesClientConfigurationType wscct = new  WorkflowServicesClientConfigurationType();
   List<ServerType> servers = wscct.getServer();
   ServerType server = new ServerType();
   server.setDefault(true);
   server.setName(serverName);
   servers.add(server);

   RemoteClientType rct = new RemoteClientType();
   rct.setServerURL("t3://stapj73:7001");
   rct.setUserName("weblogic");
   rct.setPassword("weblogic"));
   rct.setInitialContextFactory("weblogic.jndi.WLInitialContextFactory");
   rct.setParticipateInClientTransaction(false);
   server.setRemoteClient(rct);
   IWorkflowServiceClient wfSvcClient = WorkflowServiceClientFactory.getWorkflowServiceClient(
                                        WorkflowServiceClientFactory.REMOTE_CLIENT, wscct, logger);

Example 2

Map<IWorkflowServiceClientConstants.CONNECTION_PROPERTY,java.lang.String> properties = new
   HashMap<IWorkflowServiceClientConstants.CONNECTION_PROPERTY,java.lang.String>();
 
properties.put(IWorkflowServiceClientConstants.CONNECTION_PROPERTY.MODE,
   IWorkflowServiceClientConstants.MODE_DYNAMIC);
 
properties.put(IWorkflowServiceClientConstants.CONNECTION_PROPERTY.SOAP_END_POINT_ROOT,
   "http://localhost:8888");
 
IWorkflowServiceClient client =
   WorkflowServiceClientFactory.getWorkflowServiceClient(WorkflowServiceClientFactory.SOAP_CLIENT,
   properties, null);

Clients can optionally pass in a java.util.logging.Logger where the client logs messages. If no logger is specified, then the workflow service client code does not log anything. The code sample below shows how a logger can be passed to the workflow service clients:
```
java.util.logging.Logger logger = ....;
 
IWorkflowServiceClient client =
 WorkflowServiceClientFactory.getWorkflowServiceClient(WorkflowServiceClientFactory.REMOTE_CLIENT,
 properties, logger);
```

Through the factory, it is possible to get the client libraries for all the workflow services. See Table 34-1 for the clients available for each of the services.

You can obtain instances of BPMIdentityService and BPMIdentityConfigService by calling the getSOAPIdentityServiceClient and getSOAPIdentityConfigServiceClient methods on WorkflowServiceClientFactory. You can obtain all other services through an instance of IWorkflowServiceClient.

The client classes use the configuration file wf_client_config.xml for the service endpoints. In the client class path, this file is in the class path directly, meaning the containing directory is in the class path. The wf_client_config.xml file contains:

A section for remote clients, as shown in the code sample below:

<remoteClient>
      <serverURL>t3://hostname.domain_name:7001</serverURL>
  <userName>weblogic</userName>
  <password>weblogic</password>
  <initialContextFactory>weblogic.jndi.WLInitialContextFactory
     </initialContextFactory>
  <participateInClientTransaction>false</participateInClientTransaction>
</remoteClient>

A section for SOAP endpoints for each of the services, as shown in the code sample below:

<soapClient>
   <rootEndPointURL>http://hostname.domain_name:7001</rootEndPointURL>
   <identityPropagation mode="dynamic" type="saml">
   <policy-references>
      <policy-reference enabled="true" category="security" 
         uri="oracle/wss10_saml_token_client_policy"/>
      </policy-references>
   </identityPropagation>
</soapClient>

The workflow client configuration XML schema definition is in the wf_client_config.xsd file.