General Session Workflow Services Call Structure

Workflows have an internal hierarchical structure that constrain both flow of control and scope of variables. A workflow (also called a Case or WFCase) contains a list of workflow Activity elements. A workflow activity contains a list of Action elements. A variable declared at the WFCase is visible to all Activity and Action elements. If a variable named color is declared at the WFCase level, and then again in an Action, they are effectively two different variables, such that changing the value of the color variable in the Action will not affect the value of the color variable from the WFCase.

Workflow services are called from workflow actions. WorkflowServices provides a set of operations that are selected through the value of the op Argument. Each operation can have a different set of arguments, so the calling ’signature’ must match the specified service itself. The general form of a workflow service action is shown in the following code example:

<Action class=’com.waveset.session.WorkflowServices’>
   <Condition/>
   <Argument name=’op’ value=workflowServiceOp/>
   <Argument name=argname1>
      <expression>value1expression</expression>
   </Argument>
   <Argument name=argname2>
      <expression>value2expression</expression>
   </Argument>
   <Argument name=argnameN>
      <expression>valueNexpression</expression>
   </Argument>
</Action>

Each of the supported workflow services has a variable number of required and optional arguments. The op argument to the session workflow services call must specify one of the provided services. This is similar to calling a method by reflection, where the name of the method to be called is similar to the name of the workflow service to be executed.

If an op argument is given that is not on the following list, the workflow services return:

’Unknown WorkflowServices op’

and the workflow context variable WF_ACTION_ERROR will be non-null.

If an op argument is given that is not on the preceding list, a workflow service returns:

’Unknown WorkflowServices op’

and the workflow context variable WF_ACTION_ERROR will be non-null.