JBoss Seam Page Flow Configuration Tips

Here are some tips for avoiding problems in defining Page Flows with JBoss Seam.

• You need the jbpm-jpdl.jar file in your ear file. It comes with the Seam download. Otherwise you will get deploy errors complaining about the class org/jbpm/graph/exe/ProcessInstance not found.

• First define page flows in files suffixed .jpdl.xml.
• File names need not match the flow names defined inside them.
  
• Put the page flow definitions in the components.xml file which must go in the META-INF dir. The relevant segment will look like this:

     <?xml version="1.0" encoding="UTF-8"?>
     <components xmlns="http://jboss.com/products/seam/components"
            xmlns:core="http://jboss.com/products/seam/core"
            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
            xmlns:bpm="http://jboss.com/products/seam/bpm">

            <bpm:jbpm>
                   <bpm:pageflow-definitions>
                  <value>myPageFlow.jpdl.xml</value>
             </bpm:pageflow-definitions>
            </bpm:jbpm>
    </components>

• When you have hierarchically dependent page flows then the file in which the more basic flow (subflow or sub-process) must be listed earlier in the the components.xml's jbpm file list.
• So for example:

•    
  
     <bpm:jbpm>
         <bpm:pageflow-definitions>
             <value>subFlow.jpdl.xml</value>
             <value>dependentFlow.jpdl.xml</value>
         </bpm:pageflow-definitions>
     </bpm:jbpm>