Using the AquaLogic Service Bus Console

Proxy Services: Message Flow

This section includes the following topics:

Overview of Message Flow

Message Flow defines the implementation of a proxy service. Message Flows can include pipeline pairs and the following nodes: Start, Route, and Branch. To learn how to implement Message Flow, see Viewing and Changing Message Flow.

This section includes the following topics:

Pipelines

A pipeline is a named sequence of stages representing a non-branching one-way processing path.

Pipelines are typed into one of three categories:

Table 15-1 Pipeline Categories

Pipeline Category	Description
Request	Request pipelines are used for processing the request path of the Message Flow.
Response	Response pipelines are used for processing the response path of the Message Flow.
Error	Error pipelines are used as error handlers.

To create the request and response paths, request and response pipelines are paired together and organized into a single-rooted tree structure. A branch node allows you to conditionally execute these pipeline pairs, and route nodes at the ends of the branches perform any request/response dispatching. This tree structure allows for a clear overview of the Message Flow behavior, making both route actions and branch conditions explicit parts of the overall design, rather than burying them deep inside a pipeline stage.

A message flow tree is constructed by chaining together instances of these top-level components:

Table 15-2 Pipeline Categories

Pipeline Category	Description
Pipeline pair node	The pipeline pair node ties together a single request and a single response pipeline into one top-level element. A pipeline pair node may have only 1 direct descendant in the message flow tree. During request processing, only the request pipeline is executed when visiting a pipeline pair node. When reversing the path for response processing, only the response pipeline is executed. To learn how to add a pipeline pair node, see Adding a Pipeline Pair Node.
Branch node	A branch node allows processing to proceed down exactly one of several possible paths. Branching is driven by a simple lookup table with each branch tagged with a simple but unique string value. A variable in the message context is designated as the lookup variable for that node, and its value is used to determine which branch to follow. If no branch matches the value of the lookup variable, then the always-present default branch is followed. Setting the value of the lookup variable must be done before reaching the branch node. This approach ensures that exceptions do not occur within the branch node itself. A branch node may have several descendants in the message flow tree: one for each branch including the default branch. To learn how to add a branch node, see Adding a Conditional Branch Node.
Route node	The route node is used to perform request/response communication with another service. It represents the boundary between request and response processing for the proxy. When the route node dispatches a request message, request processing is considered finished. When the route node receives a response message, response processing begins. The route node itself has support for conditional routing as well as outbound and response transformations. You can choose whether conditions appear inside the route node or up in the message flow tree as branch nodes—it depends upon whether the condition is important enough to call out as part of the message flow tree structure. As the route node represents the boundary between request and response processing, it cannot have any descendants in the message flow tree. To learn how to add a route node, see Adding a Route Node.

Pipeline Category

Description

Pipeline pair node

The pipeline pair node ties together a single request and a single response pipeline into one top-level element. A pipeline pair node may have only 1 direct descendant in the message flow tree. During request processing, only the request pipeline is executed when visiting a pipeline pair node. When reversing the path for response processing, only the response pipeline is executed.

To learn how to add a pipeline pair node, see Adding a Pipeline Pair Node.

Branch node

A branch node allows processing to proceed down exactly one of several possible paths. Branching is driven by a simple lookup table with each branch tagged with a simple but unique string value. A variable in the message context is designated as the lookup variable for that node, and its value is used to determine which branch to follow. If no branch matches the value of the lookup variable, then the always-present default branch is followed. Setting the value of the lookup variable must be done before reaching the branch node. This approach ensures that exceptions do not occur within the branch node itself. A branch node may have several descendants in the message flow tree: one for each branch including the default branch.

To learn how to add a branch node, see Adding a Conditional Branch Node.

Route node

The route node is used to perform request/response communication with another service. It represents the boundary between request and response processing for the proxy. When the route node dispatches a request message, request processing is considered finished. When the route node receives a response message, response processing begins. The route node itself has support for conditional routing as well as outbound and response transformations.

You can choose whether conditions appear inside the route node or up in the message flow tree as branch nodes—it depends upon whether the condition is important enough to call out as part of the message flow tree structure.

As the route node represents the boundary between request and response processing, it cannot have any descendants in the message flow tree.

To learn how to add a route node, see Adding a Route Node.

Message Execution

The following table demonstrates the journey of a message:

Table 15-3 Message Journey

Node	What Happens to the Message?
Request Processing	Request processing begins at the root of the message flow tree
Pipeline Pair	Executes the request pipeline only
Branch	Evaluates the lookup table and proceeds down the relevant branch
Route	Performs the route along with any outbound/response transformations. Note: Whether or not any routing is performed, the route node represents a change from request processing to response processing. When a response comes in, it reverses the path it took for the request. The same thing occurs for any request path that ends without a route node - it initiates response processing and walks back up the tree, but without waiting for any response.
Response Processing	See Route.
Pipeline Pair	Executes the response pipeline
Branch	Continues with the element that preceded the branch
Root of the Tree	Sends the response back to the client

Building a Message Flow Tree

Any element may appear at the root of the message flow tree. One of the simplest of Message Flow designs is to have just a route node at the top representing the entire tree. There is also no restriction on what two elements may be chained together. For example, two pipeline pair nodes may be chained together without a branching node in between. With regards to branching, each branch may start with a different element - one branch may immediately terminate with a route node, another may be followed by a pipeline pair and yet another may have no descendant whatsoever. In the latter case, a branch with no descendants means that response processing begins immediately if that branch is selected. In general, however, a message flow tree is likely to come in two forms: for non-operational services, the tree is likely to consist of a single pipeline pair at the root followed by a route node. For operational services, the tree is likely to consist again of a single pipeline pair at the root, followed by a branch node based on operation, with each branch consisting of a pipeline pair followed by a route node.

Operational Branching

Since Message Flow is typically used with WSDL-based services, there is frequently a need to perform processing that is operation-specific. Rather than requiring you to manually configure a branching node based on operation, AquaLogic Service Bus provides a zero-configuration branching node that automatically branches based on operation. A branch is created for each operation defined on the service; the branching variable is $operation.

To learn how to add an operational branch node, see Adding an Operational Branch Node.

Viewing and Changing Message Flow

The Edit Message Flow page enables you to view and change the Message Flow of a specific proxy service. To learn more about Message Flow, see Overview of Message Flow. To learn more about proxy services, see Overview of Proxy Services.

To View and Change the Message Flow

If you have not already done so, from the left navigation pane, under Change Center, click Create to create a new session for making changes to the current configuration. To learn more, see Using the Change Center.

From the left navigation pane, select Proxy Services under Resource Browser. The Summary of Proxy Services page is displayed.

Alternatively, you can select a project or folder from under Project Explorer to display the project or folder's list of resources.

On the Summary of Proxy Services page, click the Edit Message Flow icon for the appropriate proxy service.

Alternatively, if you selected a project or folder, click the Edit Message Flow icon for the appropriate proxy service in the list of resources.
The Edit Message Flow page is displayed. The page includes the following functionality:

An icon that signifies the Start node for the proxy service, which you can click to add pipeline pair nodes, route nodes, and conditional and operational branches, and error handling for the service.
In the left navigation pane, a map of the Message Flow, which enables you to link to the pages associated with the various objects in the Message Flow. Click the name of an object to display the page associated with that object. When you add objects, the left navigation pane adds the appropriate links to the Message Flow map. If you have not yet constructed the Message Flow for this proxy service, the Message Flow contains links to the Edit Message Flow page only.

Do one of the following:

Table 15-4 Edit Message Flow Page

To...	Complete This Step...
Add a pipeline pair node	Click the Proxy Service icon, then click Add Pipeline Pair. To learn more, see Adding a Pipeline Pair Node.
Add a route node	Click the Proxy Service icon, then click Add Route Node. To learn more, see Adding a Route Node.
Add a conditional branch node	Click the Proxy Service icon, then click Add Conditional Branch Node. To learn more, see Adding a Conditional Branch Node.
Add an operational branch node	Click the Proxy Service icon, then click Add Operational Branch Node. To learn more, see Adding an Operational Branch Node.
Paste a route node that you cut or copied from the message flow of another proxy service	Click the Proxy Service icon, then click Paste Route Node. Note: This option is not available if you have not cut or copied a route node.
Add error handling for this proxy service	Click the Proxy Service icon, then click Add Service Error Handler. To learn more, see Adding Error Handling for the Proxy Service.
Save the updates and return to the Summary of Proxy Services page	Click Save.
Disregard changes and return to the Summary of Proxy Services page	Click Cancel.
Clear the changes and remain on the Edit Message Flow page	Click Clear.
Discard your changes and exit the message flow	Click Cancel All. When you confirm that you want to exit the Message Flow, the Summary of Proxy Services page is displayed if you initially clicked the Edit Message Flow icon for the proxy service on that page or the Project View or Folder View pages are displayed if you clicked the Edit Message Flow icon for the proxy service on those pages.

Note: When you click Save, the Message Flow is updated in the current session. When you have finished making changes to this configuration, from the left navigation pane, click Activate under Change Center. The session ends and the core configuration is updated. Alternatively, click Discard at any time during the session to delete the changes you have made so far in the current session.

Adding a Pipeline Pair Node

The Edit Message Flow page enables you to add a pipeline pair node. A pipeline pair node consists of a request pipeline and a response pipeline. Message Flows can include zero or more pipeline pair nodes: request and response pipelines for the proxy service (or for the operations on the service), and error handler pipelines that can be defined for stages, pipelines, and proxy services. Pipelines can include one or more stages, which in turn include actions. To learn more, see Overview of Message Flow.

To Add a Pipeline Pair Node

On the Summary of Proxy Services page in the Resource Browser, click the Edit Message Flow icon for the appropriate proxy service. Alternatively, if you are in the Project Explorer module, click the Edit Message Flow icon for the appropriate proxy service in the list of resources for a selected project or folder.
The Edit Message Flow page is displayed for the proxy service you selected. The page includes the following functionality:

An icon that signifies the Start node for the proxy service, which you can click to add pipeline pair nodes, route nodes, and conditional and operational branches, and error handling for the service.
In the left navigation pane, a map of the Message Flow, which enables you to link to the pages associated with the various objects in the Message Flow.

Click the Proxy Service icon, then click Add Pipeline Pair.

The Pipeline Pair Node icon and a default name are displayed.

To change the default name and add a description for the pipeline pair node, do the following:

Click the Pipeline Pair Node icon, click Edit, then click Name and Description.

In the Name field, enter a new name for the pipeline pair node.

In the Description field, enter a description for the pipeline pair node.

To save the changes, click Save. The Pipeline Pair Node icon and the name you assigned are displayed.

When you save the pipeline pair node, do one of the following:

Table 15-5 Pipeline Pair Node

To...	Complete This Step...
Add a stage to a pipeline	Click the appropriate request or response pipeline, then click Add Stage. To learn more, see Adding a Stage.
Add actions to a pipeline	Click the Stage icon for the appropriate pipeline (if you have already created a stage), click Edit, then click Stage. To learn more, see Adding an Action.
Paste a stage that you cut or copied from a different pipeline pair within the message flow of this proxy service or from the message flow of a different proxy service	Click the Pipeline Pair Node icon for the pipeline pair you created, then click Paste Stage. Alternatively, click the Stage icon in the appropriate pipeline (if you have already created a stage), then click Paste.
Add error handling for this pipeline	Click the Pipeline Pair Node icon for the pipeline pair you created, then click Add Pipeline Error Handler. To learn more, see Adding Pipeline Error Handling.
Add another pipeline pair node	Click the Pipeline Pair Node icon for the pipeline pair you created, click Add, then click Add Pipeline Pair. Alternatively, you can click the Proxy Service icon again, then click Add Pipeline Pair.
Add a route node	Click the Pipeline Pair Node icon for the pipeline pair you created, click Add, then click Add Route Node. To learn more, see Adding a Route Node.
Add a conditional branch node after the pipeline pair node	Click the Pipeline Pair Node icon for the pipeline pair you created, click Add, then click Add Conditional Branch Node. To learn more, see Adding a Conditional Branch Node.
Add an operational branch node after the pipeline pair node	Click the Pipeline Pair Node icon for the pipeline pair you created, click Add, then click Add Operational Branch Node. To learn more, see Adding an Operational Branch Node.
Edit the name and description of the pipeline pair node	Click the Pipeline Pair Node icon for the pipeline pair you created, click Edit, then click Name and Description. Note: When you rename a pipeline or a route node, the number of messages displayed on the Dashboard page in the Monitoring module may not correlate with those of other components due to the pipeline counters being reset to zero. This is because AquaLogic Service Bus treats the rename as a delete and recreate action. The numbers should correlate again after a time period equal to the service's monitoring interval has elapsed.
Paste a route node that you cut or copied from the message flow of another proxy service	Click the Pipeline Pair Node icon for the pipeline pair you created, then click Paste Route Node. Note: This option is not available if you have not cut or copied a route node.
Delete the pipeline pair node	Click the Pipeline Pair Node icon for the pipeline pair you created, then click Delete.
Add error handling for this proxy service	Click the Proxy Service icon, then click Add Service Error Handler. To learn more, see Adding Error Handling for the Proxy Service.
Insert a conditional branch node between the start node of the proxy service and the pipeline pair node	Click the Proxy Service icon, then click Create Conditional Branch Node. To learn more, see Adding a Conditional Branch Node
Insert an operational branch node between the start node of the proxy service and the pipeline pair node	Click the Proxy Service icon, then click Create Operational Branch Node. To learn more, see Adding an Operational Branch Node.
Save the updates and return to the Summary of Proxy Services page	Click Save.
Disregard changes and return to the Summary of Proxy Services page	Click Cancel.
Clear the changes and remain on the Edit Message Flow page	Click Clear.
Discard your changes and exit the message flow	Click Cancel All. When you confirm that you want to exit the Message Flow, the Summary of Proxy Services page is displayed if you initially clicked the Edit Message Flow icon for the proxy service on that page or the Project View or Folder View pages are displayed if you clicked the Edit Message Flow icon for the proxy service on those pages.

Adding a Conditional Branch Node

The Edit Message Flow page enables you to add a conditional branch node. A branch node allows processing to proceed down exactly one of several possible paths. To learn more, see Overview of Message Flow.

To Add a Conditional Branch Node

On the Summary of Proxy Services page, click the Edit Message Flow icon for the appropriate proxy service. Alternatively, if you are in the Project Explorer module, click the Edit Message Flow icon for the appropriate proxy service in the list of resources for a selected project or folder.

The Edit Message Flow page is displayed for the proxy service you selected. The page includes the following functionality:

An icon that signifies the Start node for the proxy service, which you can click to add pipeline pair nodes, route nodes, and conditional and operational branches, and add error handling for the service.
In the left navigation pane, a map of the Message Flow, which enables you to link to the pages associated with the various objects in the Message Flow.
If you have already added a pipeline pair node or service error handler, these icons are displayed.

Do one of the following:

To add a conditional branch node at the end of the message flow, click the appropriate icon, then select Add Conditional Branch Node. The Branch Node icon and a default name are displayed.
To insert a conditional branch node at a specific point in the message flow, click the appropriate icon, then click Create Conditional Branch Node. The Branch Node icon and a default name are displayed, and the nodes after the inserted branch node are moved to the default branch of the new branch node.

To change the default name and add a description for the branch node, do the following:

Click the Conditional Branch Node icon, click Edit, then click Name and Description.

In the Name field, enter a new name for the branch node.

In the Description field, enter a description for the branch node.

To save the branch node, click Save. The Conditional Branch Node icon and the name you assigned to the branch node are displayed.

To add branch definitions, click the Conditional Branch Node icon, click Edit, then click Branch Node. The Edit Branch Node page is displayed.

In the Branch Definitions panel, do the following:

In the Selected Path field, click Edit to add an XPath expression. To learn more, see Using the XPath Expression Editor.

In the Variable field, enter a context variable.

In the Operator field, select =, !=, <, >, <=, or >=.

In the Value field, enter a value for the branch.

In the Label field, enter a label for the branch.

Do one of the following:

Table 15-6 Adding a Conditional Branch Node

To...	Complete This Step...
Add another branch definition	Click Add a New Branch from the flyout menu of the Options column.
Delete a branch definition	Click Delete this Branch from the flyout menu of the Options column.
Move a branch down the list of definitions	Click Move Branch Down from the flyout menu of the Options column. Note: This option displays only when more than one branch definition exists.
Move a branch up the list of definitions	Click Move Branch Up from the flyout menu of the Options column. Note: This option displays only when more than one branch definition exists.

When you have finished working with the definitions, do one of the following:

Table 15-7 Adding a Conditional Branch Node

To...	Complete This Step...
Update the branch and return to the Edit Message Flow page	Click Save.
Disregard changes and return to the Edit Message Flow page	Click Cancel.
Disregard changes and remain on the Edit Branch Node page	Click Clear.
Discard your changes and exit the message flow	Click Cancel All. When you confirm that you want to exit the Message Flow, the Summary of Proxy Services page is displayed if you initially clicked the Edit Message Flow icon for the proxy service on that page or the Project View or Folder View pages are displayed if you clicked the Edit Message Flow icon for the proxy service on those pages.

When you save the branch node, do one of the following:

Table 15-8 Adding a Conditional Branch Node

To...	Complete This Step...
Add a pipeline pair node	Click the Proxy Service icon, then click Add Pipeline Pair. To learn more, see Adding a Pipeline Pair Node.
Add a stage to an existing pipeline	Click the appropriate request or response pipeline, then click Add Stage. To learn more, see Adding a Stage.
Add actions to an existing pipeline	Click the Stage icon for the appropriate pipeline, click Edit, then click Stage. To learn more, see Adding an Action.
Add error handling for this proxy service	Click the Proxy Service icon, then click Add Service Error Handler. To learn more, see Adding Error Handling for the Proxy Service.
Delete the branch node	Click the Conditional Branch icon, then click Delete Branch Node.
Save the updates and return to the Summary of Proxy Services page	Click Save.
Disregard changes and return to the Summary of Proxy Services page	Click Cancel.
Clear the changes and remain on the Edit Message Flow page	Click Clear.
Discard your changes and exit the message flow	Click Cancel All. When you confirm that you want to exit the Message Flow, the Summary of Proxy Services page is displayed if you initially clicked the Edit Message Flow icon for the proxy service on that page or the Project View or Folder View pages are displayed if you clicked the Edit Message Flow icon for the proxy service on those pages.

Adding an Operational Branch Node

The Edit Message Flow page enables you to add an operational branch node.

To Add an Operational Branch Node

The Edit Message Flow page is displayed for the proxy service you selected. The page includes the following functionality:

An icon that signifies the Start node for the proxy service, which you can click to add pipeline pair nodes, route nodes, and conditional and operational branches, and add error handling for the service.
In the left navigation pane, a map of the Message Flow, which enables you to link to the pages associated with the various objects in the Message Flow.
If you have already added a pipeline pair node or service error handler, these icons are displayed.

Do one of the following:

To add an operational branch node at the end of the message flow, click the appropriate icon, then select Add Operational Branch Node. The Branch Node icon and a default name are displayed.
To insert an operational branch node at a specific point in the message flow, click the appropriate icon, then click Create Operational Branch Node. The Branch Node icon and a default name are displayed, and the nodes after the inserted branch node are moved to the default branch of the new branch node.

To change the default name and add a description for the branch node, do the following:

Click the Operational Branch Node icon, click Edit, then click Name and Description.

In the Name field, enter a new name for the branch node.

In the Description field, enter a description for the branch node.

To save the branch node, click Save. The Operational Branch Node icon and the name you assigned to the branch node are displayed.

To add branch definitions, select the branch node, click Edit, then click Branch Node. The Edit a Branch page is displayed.

In the Operation Branch Definitions panel, select a service operation.

Do one of the following:

Table 15-9 Adding an Operational Branch Node

To...	Complete This Step...
Add another branch definition	Click Add a New Branch from the flyout menu of the Options column.
Delete a branch definition	Click Delete this Branch from the flyout menu of the Options column.
Move a branch down the list of definitions	Click Move Branch Down from the flyout menu of the Options column. Note: This option displays only when more than one branch definition exists.
Move a branch up the list of definitions	Click Move Branch Up from the flyout menu of the Options column. Note: This option displays only when more than one branch definition exists.

When you have finished working with the definitions, do one of the following:

Table 15-10 Adding an Operational Branch Node

To...	Complete This Step...
Update the branch and return to the Edit Message Flow page	Click Save.
Disregard changes and return to the Edit Message Flow page	Click Cancel.
Disregard changes and remain on the Edit Branch Node page	Click Clear.
Discard your changes and exit the message flow	Click Cancel All. When you confirm that you want to exit the Message Flow, the Summary of Proxy Services page is displayed if you initially clicked the Edit Message Flow icon for the proxy service on that page or the Project View or Folder View pages are displayed if you clicked the Edit Message Flow icon for the proxy service on those pages.

When you saved the branch node, do one of the following:

Table 15-11 Adding an Operational Branch Node

To...	Complete This Step...
Add a pipeline pair node	Click the Proxy Service icon, then click Add Pipeline Pair. To learn more, see Adding a Pipeline Pair Node.
Add a stage to an existing pipeline	Click the appropriate request or response pipeline, then click Add Stage. To learn more, see Adding a Stage.
Add actions to an existing pipeline	Click the Stage icon for the appropriate pipeline, click Edit, then click Stage. To learn more, see Adding an Action.
Add a conditional branch node	Click the Proxy Service icon, then click Add Conditional Branch Node. To learn more, see Adding a Conditional Branch Node.
Add a route node	Click the Proxy Service icon, then click Add Route Node. To learn more, see Adding a Route Node.
Add error handling for this proxy service	Click the Proxy Service icon, then click Add Service Error Handler. To learn more, see Adding Error Handling for the Proxy Service.
Delete the branch node	Click the Operational Branch icon, then click Delete Branch Node.
Save the updates and return to the Summary of Proxy Services page	Click Save.
Disregard changes and return to the Summary of Proxy Services page	Click Cancel.
Clear the changes and remain on the Edit Message Flow page	Click Clear.
Discard your changes and exit the message flow	Click Cancel All. When you confirm that you want to exit the Message Flow, the Summary of Proxy Services page is displayed if you initially clicked the Edit Message Flow icon for the proxy service on that page or the Project View or Folder View pages are displayed if you clicked the Edit Message Flow icon for the proxy service on those pages.

Adding a Stage

The Edit Message Flow page enables you to add a stage. A stage is a container of actions. To learn more, see Overview of Message Flow.

Note: You must create a pipeline pair node before you can add a stage. To learn more, see Adding a Pipeline Pair Node.

To Add a Stage

The Edit Message Flow page is displayed.

Expand an existing pipeline pair node to view the pipeline pair, which consists of request and response pipelines.

Click the pipeline to which you want to add the stage, then click Add Stage.

The Stage icon and a default name are displayed.

To change the default name and add a description for the stage, do the following:

Click the Stage icon, click Edit, then click Name and Description.

In the Name field, enter a new name for the stage.

In the Description field, enter a description for the stage.

To save the changes, click Save. The Stage icon and the name you assigned to the stage are displayed.

When you save the stage, do one of the following:

Table 15-12 Adding a Stage

To...	Complete This Step...
Add actions	Click the Stage icon, click Edit, then click Stage. To learn more, see Adding an Action.
Add error handling for the stage	Click the Stage icon, then click Stage Error Handler. To learn more, see Adding Stage Error Handling.
Delete a stage	Click the appropriate Stage icon, then click Delete.
Cut a stage	Click the appropriate Stage icon, then click Cut.
Copy a stage	Click the appropriate Stage icon, then click Copy.
Paste a stage that you cut or copied from a different pipeline pair within the message flow of this proxy service or from the message flow of a different proxy service	Click the Stage icon in the appropriate pipeline, then click Paste. Alternatively, you can click the Pipeline Pair Node icon for the pipeline pair you created, then click Paste Stage.
Add error handling for this pipeline	Click the pipeline, then click Add Pipeline Error Handler. To learn more, see Adding Pipeline Error Handling.
Add another pipeline pair	Click the Proxy Service icon, then click Add Pipeline Pair. Alternatively, you can click an existing Pipeline Pair Node icon, click Add, then click Add Pipeline Pair. To learn more, see Adding a Pipeline Pair Node.
Add error handling for this proxy service	Click the Proxy Service icon, then click Add Service Error Handler. To learn more, see Adding Error Handling for the Proxy Service.
Add a route node	Click the Pipeline Pair Node icon, click Add, then click Add Route Node. To learn more, see Adding a Route Node.
Add a conditional branch node	Click the Pipeline Pair Node icon, click Add, then click Add Conditional Branch Node. To learn more, see Adding a Conditional Branch Node.
Insert a conditional branch node between the start node of the proxy service and the pipeline pair node	Click the Proxy Service icon, then click Create Conditional Branch Node. To learn more, see Adding a Conditional Branch Node
Insert an operational branch node between the start node of the proxy service and the pipeline pair node	Click the Proxy Service icon, then click Create Operational Branch Node. To learn more, see Adding an Operational Branch Node.
Save the updates and return to the Summary of Proxy Services page	Click Save.
Disregard changes and return to the Summary of Proxy Services page	Click Cancel.
Clear the unsaved changes and remain on the Edit Message Flow page	Click Clear.
Discard your changes and exit the message flow	Click Cancel All. When you confirm that you want to exit the Message Flow, the Summary of Proxy Services page is displayed if you initially clicked the Edit Message Flow icon for the proxy service on that page or the Project View or Folder View pages are displayed if you clicked the Edit Message Flow icon for the proxy service on those pages.

Adding a Route Node

The Edit Message Flow page enables you to add a route node. The route node is used to perform one way communication, such as using file or email transport. It represents the boundary between request and response processing for the proxy service. When the route node dispatches a request message, request processing is considered finished. When the route node receives a response message, response processing begins. To learn more about Message Flow, see Overview of Message Flow.

AquaLogic Service Bus supports reliable messaging. When messages are routed to another service from a route node, the default quality of service (QoS) is exactly once if the proxy service transport is defines as JMS/XA; otherwise best effort QoS is supported. Exactly once reliability means that messages are delivered from inbound to outbound exactly once, assuming a terminating error does not occur before the outbound message send is initiated. The exactly once delivery reliability is a hint, not a directive. When exactly once is specified, exactly once reliability is provided if possible. If exactly once is not possible, then at least once delivery semantics are attempted; if that is not possible, best effort delivery is performed.

At least once semantics means the message is delivered to the outbound from the inbound at least once, assuming a terminating error does not occur before the outbound message send is initiated. Delivery is considered satisfied even if the target service responds with a transport-level error. However it is not satisfied in the case of a timeout, a failure to connect, or a broken communication link. If fail over URLs are specified, at least once semantics is provided with respect to at least one of the URLs.

Best effort means that there is no reliable messaging and there is no elimination of duplicate messages—however, performance is optimized.

To override the default exactly once quality of service attribute, you must set the qualityOfService in the outbound message context variable ($outbound). For more information, see Message Context Schema.

To Add a Route Node

The Edit Message Flow page is displayed for the proxy service you selected. The page includes the following functionality:

An icon that signifies the Start node for the proxy service, which you can click to add pipeline pair nodes, route nodes, and conditional and operational branches, and add error handling for the service.
In the left navigation pane, a map of the Message Flow, which enables you to link to the pages associated with the various objects in the Message Flow.
If you have already added a pipeline pair node or service error handler, these icons are displayed.

To add a route node, do one of the following:

Click the Proxy Service icon, then select Add Route Node.
Click the Pipeline Pair Node icon of an existing pipeline pair, click Add, then click Add Route Node.

The Route Node icon and a default name are displayed.

To change the default name and add a description for the route node, do the following:

Click the Route Node icon, click Edit, then click Name and Description.

In the Name field, enter a new name for the route node.

In the Description field, enter a description for the route node.

To save the changes, click Save. The Route Node icon and the name you assigned to the route node are displayed.

Note: When you rename a pipeline or a route node, the number of messages displayed on the Dashboard page in the Monitoring module may not correlate with those of other components due to the pipeline counters being reset to zero. This is because AquaLogic Service Bus treats the rename as a delete and recreate action. The numbers should correlate again after a time period equal to the service's monitoring interval has elapsed.

Click the route node, click Edit, then click Route Node. The Edit Stage Configuration page is displayed. Continue in Adding Route Node Actions.

When you have finished adding routing node actions and saved the route node, do one of the following:

Table 15-13 Adding a Route Node

To...	Complete This Step...
Add a pipeline pair node	Click the Proxy Service icon, then click Add Pipeline Pair. To learn more, see Adding a Pipeline Pair Node.
Add error handling for this proxy service	Click the Proxy Service icon, then click Add Service Error Handler. To learn more, see Adding Error Handling for the Proxy Service.
Add a stage to an existing pipeline	Click the appropriate request or response pipeline, then click Add Stage. To learn more, see Adding a Stage.
Add actions to an existing pipeline	Click the Stage icon for the appropriate pipeline, then click Edit Stage. To learn more, see Adding an Action.
Edit the route node actions	Click the Route Node icon, click Edit, then click Route Node.
Add an error handler for the route node	Click the Route Node icon, then click Add Error Handler. To learn more, see Adding Error Handling for the Route Node.
Cut a stage	Click the Route Node icon, then click Cut.
Copy a stage	Click the Route Node icon, then click Copy.
Paste a route node that you cut or copied from the message flow of a different proxy service	Click the Route Node icon in the appropriate pipeline, then click Paste Route Node.
Insert a conditional branch node between the start node of the proxy service and the pipeline pair node	Click the Proxy Service icon, then click Create Conditional Branch Node. To learn more, see Adding a Conditional Branch Node
Insert an operational branch node between the start node of the proxy service and the pipeline pair node	Click the Proxy Service icon, then click Create Operational Branch Node. To learn more, see Adding an Operational Branch Node.
Save the updates and return to the Summary of Proxy Services page	Click Save.
Disregard changes and return to the Summary of Proxy Services page	Click Cancel.
Clear the changes and remain on the Edit Message Flow page	Click Clear.
Discard your changes and exit the message flow	Click Cancel All. When you confirm that you want to exit the Message Flow, the Summary of Proxy Services page is displayed if you initially clicked the Edit Message Flow icon for the proxy service on that page or the Project View or Folder View pages are displayed if you clicked the Edit Message Flow icon for the proxy service on those pages.

Adding Route Node Actions

The Edit Stage Configuration page enables you to add route node actions when you click Edit, then click Route Node on the Edit Message Flow page. Route node actions define the handling of messages as they flow through the route node of the proxy service. To learn more about Message Flow, see Overview of Message Flow.

To Add a Route Node Action

The Edit Message Flow page is displayed.

Click the Route Node icon, click Edit, then click Route Node. The Edit Stage Configuration page is displayed.

To add a route node action, click Add an Action, then select an action type. The list of action types and the procedures to configure them are displayed in the following table.

Note: To learn more about actions, see Modeling Message Flow in AquaLogic Service Bus in the BEA AquaLogic Service Bus User Guide for usage scenarios, design patterns, and best practices.

Table 15-14 Adding Route Node Actions

To...	Complete These Steps...
If... Then...	Assign if then else actions based on the Boolean result of an XQuery expression: Note: Condition actions can be nested. However, there is a nesting limit of 4 cumulative levels in the stage editor. If you attempt to add a 5th level, this nesting action is not displayed. Cumulative levels include all branching actions: If... Then... Conditions, Publish Tables, and Route Tables. For example, you can have 2 levels of conditionals, then a publish table with a route table inside of it, bringing the total to 4 levels. If you attempt to add another conditional (to the last publish table), the conditional is not displayed. 1. Click Add an Action, then select If... Then... The If... Then... action is displayed, which includes the following functionality: An If...Then... icon. If... condition then..., which is a link from which you can edit the condition. A field in which you can add request and response actions 2. Click Condition. The Edit an XQuery Condition page is displayed. To learn more, see Using the XQuery Condition Editor. 3. When you have finished editing the XQuery condition, click Add an Action, then select an action that you want to associate with the condition. Note: In the route node, you can select the Routing or Routing Table actions only. To learn more about these actions, see the appropriate procedure in this table. However, these actions can contain request and response actions inside of them. To learn more, see the table of actions in Adding a Route Node. 4. If necessary, click the If...Then... icon to add else-if conditions or else conditions, then click Add an Action to associate actions with these conditions. 5. Continue to the next step.
Routing	Note: This is a terminal action, which means you cannot add another action after this one. However, this action can contain request and response actions inside of it. Identify a target service for the message and configure how the message is routed to that service: 1. Click Add an Action, then select Routing. The Routing action is displayed, which includes the following functionality: A Routing icon A Service link that you can click to select a service A field in which you can add request and response actions 2. Click Service. The Service Browser is displayed. 3. Select a service from the list, then click Submit. The service is displayed instead of the default link. 4. In the Request Actions field, click Add an Action to add an action, then select an action that you want to associate with the service. You can add more than one action. To learn more about the type of actions you want to add, see the table of actions in Adding an Action. 5. In the Response Actions field, click Add an Action to add an action, then select an action that you want to associate with the service. You can add more than one action. To learn more about the type of actions you want to add, see the table of actions in Adding an Action. 6. When you have finished adding actions, continue to the next step.
Routing Table	Note: This is a terminal action, which means you cannot add another action after this one. However, this action can contain request and response actions inside of it. A routing table is a set of routes wrapped in a switch-style condition table. It is a short-hand construct that allows different routes to be selected based upon the results of a single XQuery expression. There is a nesting limit of 4 cumulative levels in the stage editor. If you attempt to add a 5th level, this nesting action is not displayed. Cumulative levels include all branching actions: If... Then... Conditions, Publish Tables, and Route Tables. For example, you can have 2 levels of conditionals, then a publish table with a route table inside of it, bringing the total to 4 levels. If you attempt to add another conditional (to the last publish table), the conditional is not displayed. Identify target services for messages and configure how the messages are routed to these services: 1. Click Add an Action, then select Routing Table. The Routing Table action is displayed, which includes the following functionality: A Routing Table icon, an Expression link in which you can edit an XQuery expression, a Diamond icon that you can use to insert new cases, a field in which you can enter a comparison operator, a A field in which you can enter a value, a Service link that you can click to select a service, and a field in which you can add request and response actions. 2. Select one of these comparison operators: =, !=, < , >, <=, or >=, then enter a value expression in the field provided. 3. Click Service. The Service Browser is displayed. 4. Select a service from the list, then click Submit. The service is displayed. 5. In the Request Actions field, click Add an Action to add an action, then select an action that you want to associate with the service. You can add more than one action. 6. In the Response Actions field, click Add an Action to add an action, then select an action that you want to associate with the service. You can add more than one action. Note: To learn more about the types of request and response actions you want to add, see the table of actions in Adding an Action. 7. When you have finished adding actions, continue to the next step. 8. To insert a new case, click the Diamond icon, then select Insert New Case. 9. Repeat steps 2-7 for the new case. You can click the Diamond icon, then select Insert Default Case to add a default case at the end whose routes are selected if none of the preceding cases is satisfied. 10. When you have finished adding cases, continue to the next step.

To...

Complete These Steps...

If... Then...

Assign if then else actions based on the Boolean result of an XQuery expression:

Note: Condition actions can be nested. However, there is a nesting limit of 4 cumulative levels in the stage editor. If you attempt to add a 5th level, this nesting action is not displayed. Cumulative levels include all branching actions: If... Then... Conditions, Publish Tables, and Route Tables. For example, you can have 2 levels of conditionals, then a publish table with a route table inside of it, bringing the total to 4 levels. If you attempt to add another conditional (to the last publish table), the conditional is not displayed.

1. Click Add an Action, then select If... Then...

The If... Then... action is displayed, which includes the following functionality:
An If...Then... icon.
If... condition then..., which is a link from which you can edit the condition.
A field in which you can add request and response actions

2. Click Condition. The Edit an XQuery Condition page is displayed. To learn more, see Using the XQuery Condition Editor.

3. When you have finished editing the XQuery condition, click Add an Action, then select an action that you want to associate with the condition.

Note: In the route node, you can select the Routing or Routing Table actions only. To learn more about these actions, see the appropriate procedure in this table. However, these actions can contain request and response actions inside of them. To learn more, see the table of actions in Adding a Route Node.

4. If necessary, click the If...Then... icon to add else-if conditions or else conditions, then click Add an Action to associate actions with these conditions.

5. Continue to the next step.

Routing

Note: This is a terminal action, which means you cannot add another action after this one. However, this action can contain request and response actions inside of it.

Identify a target service for the message and configure how the message is routed to that service:

1. Click Add an Action, then select Routing.

The Routing action is displayed, which includes the following functionality:
A Routing icon
A Service link that you can click to select a service
A field in which you can add request and response actions

2. Click Service. The Service Browser is displayed.

3. Select a service from the list, then click Submit. The service is displayed instead of the default link.

4. In the Request Actions field, click Add an Action to add an action, then select an action that you want to associate with the service. You can add more than one action. To learn more about the type of actions you want to add, see the table of actions in Adding an Action.

5. In the Response Actions field, click Add an Action to add an action, then select an action that you want to associate with the service. You can add more than one action. To learn more about the type of actions you want to add, see the table of actions in Adding an Action.

6. When you have finished adding actions, continue to the next step.

Routing Table

Note: This is a terminal action, which means you cannot add another action after this one. However, this action can contain request and response actions inside of it.

A routing table is a set of routes wrapped in a switch-style condition table. It is a short-hand construct that allows different routes to be selected based upon the results of a single XQuery expression.

There is a nesting limit of 4 cumulative levels in the stage editor. If you attempt to add a 5th level, this nesting action is not displayed. Cumulative levels include all branching actions: If... Then... Conditions, Publish Tables, and Route Tables. For example, you can have 2 levels of conditionals, then a publish table with a route table inside of it, bringing the total to 4 levels. If you attempt to add another conditional (to the last publish table), the conditional is not displayed.

Identify target services for messages and configure how the messages are routed to these services:

1. Click Add an Action, then select Routing Table. The Routing Table action is displayed, which includes the following functionality:

A Routing Table icon, an Expression link in which you can edit an XQuery expression, a Diamond icon that you can use to insert new cases, a field in which you can enter a comparison operator, a A field in which you can enter a value, a Service link that you can click to select a service, and a field in which you can add request and response actions.

2. Select one of these comparison operators: =, !=, < , >, <=, or >=, then enter a value expression in the field provided.

3. Click Service. The Service Browser is displayed.

4. Select a service from the list, then click Submit. The service is displayed.

5. In the Request Actions field, click Add an Action to add an action, then select an action that you want to associate with the service. You can add more than one action.

6. In the Response Actions field, click Add an Action to add an action, then select an action that you want to associate with the service. You can add more than one action.

Note: To learn more about the types of request and response actions you want to add, see the table of actions in Adding an Action.

7. When you have finished adding actions, continue to the next step.

8. To insert a new case, click the Diamond icon, then select Insert New Case.

9. Repeat steps 2-7 for the new case. You can click the Diamond icon, then select Insert Default Case to add a default case at the end whose routes are selected if none of the preceding cases is satisfied.

10. When you have finished adding cases, continue to the next step.

When you have finished adding route node actions, do one of the following:

Table 15-15 Adding Route Node Actions

To...	Complete This Step...
Delete an action	Click the appropriate icon, then click Delete this Action. The action is deleted.
Move an action down	Click the appropriate icon, then click Move Action Down. The action is moved below the next action contained in this stage. Note: This option is displayed only when there are two or more actions contained in the stage.
Move an action up	Click the appropriate icon, then click Move Action Up. The action is moved above the previous action contained in this stage. Note: This option is displayed only when there are two or more actions contained in the stage.
Cut an action	Click the appropriate icon, then click Cut.
Copy an action	Click the appropriate icon, then click Copy.
Paste an action that you have cut or copied from within this stage	Click the appropriate icon, then click Paste Action. Note: You cannot paste actions across stages; you can only paste actions that are inside the same stage.
Save the updates and return to the Edit Message Flow page	Click Save.
Disregard changes and return to the Edit Message Flow page	Click Cancel.
Clear the unsaved changes and remain on the Edit Stage Configuration page	Click Clear.
Discard your changes and exit the message flow	Click Cancel All. When you confirm that you want to exit the Message Flow, the Summary of Proxy Services page is displayed if you initially clicked the Edit Message Flow icon for the proxy service on that page or the Project View or Folder View pages are displayed if you clicked the Edit Message Flow icon for the proxy service on those pages.

When you save the actions, do one of the following:

Table 15-16 Adding Route Node Actions

To...	Complete This Step...
Edit the route node name and description	Click the Route Node icon, click Edit, then click Name and Description.
Add an error handler for the route node	Click the Route Node icon, then click Add Error Handler. To learn more, see Adding Error Handling for the Route Node.
Save the updates and return to the Summary of Proxy Services page	Click Save.
Disregard changes and return to the Summary of Proxy Services page	Click Cancel.
Clear the changes and remain on the Edit Message Flow page	Click Clear.
Discard your changes and exit the message flow	Click Cancel All. When you confirm that you want to exit the Message Flow, the Summary of Proxy Services page is displayed if you initially clicked the Edit Message Flow icon for the proxy service on that page or the Project View or Folder View pages are displayed if you clicked the Edit Message Flow icon for the proxy service on those pages.

Viewing and Changing Conditional Branch Details

The Edit Branch Node page enables you to view and change conditional branch details. To learn more about branch nodes, see Adding a Conditional Branch Node and Overview of Message Flow.

Note: If you want to edit an operational branch, see Viewing and Changing Operational Branch Details.

To View and Change Conditional Branch Details

The Edit Message Flow page is displayed for the proxy service you selected. The page includes the following functionality:

A proxy service icon
The name of the proxy service
A pipeline pair node icon and name if you have already added a pipeline pair node
The conditional branch node icon and the name of the branch node
A route node icon if you have already added a route node
In the left navigation pane, a map of the Message Flow, which enables you to link to the pages associated with the various objects in the Message Flow.

Click the Conditional Branch Node icon, click Edit, then click Branch Node. Alternatively, from the left navigation pane, you can select the branch node from the map of the Message Flow.

The Branch Configuration fields and the Branch Definitions are displayed.

Do one of the following:

Table 15-17 Branch Configuration Fields and Branch Definitions

To...	Complete This Step...
Edit the XPath expression in the Selected Path field	Click Edit. To learn more, see Using the XPath Expression Editor.
Add another branch definition	Click Add a New Branch from the flyout menu of the Options column.
Delete a branch definition	Click Delete this Branch from the flyout menu of the Options column.
Move a branch down the list of definitions	Click Move Branch Down from the flyout menu of the Options column. Note: This option displays only when more than one branch definition exists.
Move a branch up the list of definitions	Click Move Branch Up from the flyout menu of the Options column. Note: This option displays only when more than one branch definition exists.

When you have finished updating the branch, do one of the following:

Table 15-18 Branch Configuration Fields and Branch Definitions

To...	Complete This Step...
Update the branch and return to the Edit Message Flow page	Click Save.
Disregard changes and return to the Edit Message Flow page	Click Cancel.
Disregard changes and remain on the Edit Branch Node page	Click Clear.
Discard your changes and exit the message flow	Click Cancel All. When you confirm that you want to exit the Message Flow, the Summary of Proxy Services page is displayed if you initially clicked the Edit Message Flow icon for the proxy service on that page or the Project View or Folder View pages are displayed if you clicked the Edit Message Flow icon for the proxy service on those pages.

Viewing and Changing Operational Branch Details

The Edit Branch Node page enables you to view and change operational branch details. To learn more about operational branches, see Adding an Operational Branch Node and Overview of Message Flow.

To View and Change Operational Branch Details

The Edit Message Flow page is displayed for the proxy service you selected. The page includes the following functionality:

A proxy service icon
The name of the proxy service
A pipeline pair node icon and name if you have already added a pipeline pair node
The conditional branch node icon and the name of the branch node
A route node icon if you have already added a route node
In the left navigation pane, a map of the Message Flow, which enables you to link to the pages associated with the various objects in the Message Flow.

Click the Operational Branch Node icon, click Edit, then click Branch Node. Alternatively, from the left navigation pane, you can select the branch from the map of the Message Flow.

The Branch Configuration fields and the Branch Definitions are displayed.

Do one of the following:

Table 15-19 Branch Configuration Fields and Branch Definitions

To...	Complete This Step...
Add another branch definition	Click Add a New Branch from the flyout menu of the Options column.
Delete a branch definition	Click Delete this Branch from the flyout menu of the Options column.
Move a branch down the list of definitions	Click Move Branch Down from the flyout menu of the Options column. Note: This option displays only when more than one branch definition exists.
Move a branch up the list of definitions	Click Move Branch Up from the flyout menu of the Options column. Note: This option displays only when more than one branch definition exists.

When you have finished updating the branch, do one of the following:

Table 15-20 Branch Configuration Fields and Branch Definitions

To...	Complete This Step...
Update the branch and return to the Edit Message Flow page	Click Save.
Disregard changes and return to the Edit Message Flow page	Click Cancel.
Disregard changes and remain on the Edit Branch Node page	Click Clear.
Discard your changes and exit the message flow	Click Cancel All. When you confirm that you want to exit the Message Flow, the Summary of Proxy Services page is displayed if you initially clicked the Edit Message Flow icon for the proxy service on that page or the Project View or Folder View pages are displayed if you clicked the Edit Message Flow icon for the proxy service on those pages.

Viewing and Changing Stage Configuration Details

The Edit Stage Configuration page enables you to edit a stage. To learn more about stages, see Adding a Stage, Adding an Action, and Overview of Message Flow.

To View and Change Stage Configuration Details

The Edit Message Flow page is displayed for the proxy service you selected. The page includes the following attributes:

A proxy service icon
The name of the proxy service
A pipeline pair node icon and name if you have already added a pipeline pair node
A route node icon if you have already added a route node
In the left navigation pane, a map of the Message Flow, which enables you to link to the pages associated with the various objects in the Message Flow.

Select the stage that you want to edit:

Expand an existing pipeline to view the pipeline pair.

In the request or response pipeline, click the Stage icon, click Edit, then click Stage.

The Edit Stage Configuration page is displayed.

Note: Alternatively, from the left navigation pane, you can select the stage from the map of the Message Flow.

Do one of the following:

Table 15-21 Edit Stage Configuration Page

To...	Complete This Step...
Add an action	Click Add an Action, then select the appropriate action. To learn more, see Adding an Action.
Delete an action	Select the action, then click Delete this Action.
Edit a variable field	Make the edits in the appropriate field.
Edit an XQuery expression	Click the expression you want to edit. To learn more, see Using the Inline XQuery Expression Editor.
Edit an XPath expression	Click the expression you want to edit. To learn more, see Using the XPath Expression Editor.
Edit an XQuery condition	Click the condition you want to edit. To learn more, see Using the XQuery Condition Editor.

When you have finished making changes, do one of the following:

Table 15-22 Edit Stage Configuration Page

To...	Complete This Step...
Move an action down	Click the appropriate icon, then click Move Action Down. The action is moved below the next action contained in this stage. Note: This option is displayed only when there are two or more actions contained in the stage.
Move an action up	Click the appropriate icon, then click Move Action Up. The action is moved above the previous action contained in this stage. Note: This option is displayed only when there are two or more actions contained in the stage.
Cut an action	Click the appropriate icon, then click Cut.
Copy an action	Click the appropriate icon, then click Copy.
Paste an action that you have cut or copied from within this stage	Click the appropriate icon, then click Paste Action. Note: You cannot paste actions across stages; you can only paste actions that are inside the same stage.
Update the stage and return to the Edit Message Flow page	Click Save.
Disregard changes and return to the Edit Message Flow page	Click Cancel.
Disregard changes and remain on the Edit Stage Configuration page	Click Clear.
Discard your changes and exit the message flow	Click Cancel All. When you confirm that you want to exit the Message Flow, the Summary of Proxy Services page is displayed if you initially clicked the Edit Message Flow icon for the proxy service on that page or the Project View or Folder View pages are displayed if you clicked the Edit Message Flow icon for the proxy service on those pages.

Proxy Services: Message Flow

Overview of Message Flow

Pipelines

Message Execution

Building a Message Flow Tree

Operational Branching

Related Topics

Viewing and Changing Message Flow

To View and Change the Message Flow

Related Topics

Adding a Pipeline Pair Node

To Add a Pipeline Pair Node

Related Topics

Adding a Conditional Branch Node

To Add a Conditional Branch Node

Related Topics

Adding an Operational Branch Node

To Add an Operational Branch Node

Related Topics

Adding a Stage

To Add a Stage

Related Topics

Adding a Route Node

To Add a Route Node

Related Topics

Adding Route Node Actions

To Add a Route Node Action

Related Topics

Viewing and Changing Conditional Branch Details

To View and Change Conditional Branch Details

Related Topics

Viewing and Changing Operational Branch Details

To View and Change Operational Branch Details

Related Topics

Viewing and Changing Stage Configuration Details

To View and Change Stage Configuration Details

Related Topics