The BPEL Service Provider ([com.fs.jlo.bpel.provider.BpelServiceProvider]) extends the PXE container to support BPEL processes execution. Installing this service provider in a PXE domain makes it possible to deploy BPEL process definitions as PXE services.

Service Provider Configuration

There are two questions that are answered at configuration time:

1. Which persistence implementation should be used?
2. Which expression / query languages will be supported?

Both of these questions are answered using the configuration properties described below.

Configuration Properties

PXE Stand-Alone Server Configuration

The PXE stand-alone server uses a configuration file — pxe-config.properties — to configure service providers. The configuration for the BPEL Service Provider, should look something like:

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# BPEL Service Provider
pxe.j2ee.provider.sp3.uri=uri:bpelProvider
pxe.j2ee.provider.sp3.class=\
  com.fs.jlo.bpel.provider.BpelServiceProvider
pxe.j2ee.provider.sp3.property.stateStoreConnectionFactory=\
  com.fs.jlo.daohib.bpel.StateStoreConnectionFactoryImpl
pxe.j2ee.provider.sp3.property.expressionLanguageFactory=\
  foo.bar.MyExpressionLanguageRuntimeImpl
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Service Deployment

A BPEL process definition must be pre-compiled into a compiled BPEL process (a .cbp file) before it can be deployed as a PXE service. This compilation can be performed either by the bpelc command or through [programmatic means]. The .cbp file must be placed in the resource repository of a PXE system, and is referenced (by URI) from the PXE service configuration in the system deployment descriptor.

Deployment Properties

Ports

A BPEL process communicates with external services through partner links, which can define a partner role and/or a my role. The partner role of a partner link is a reference to an external service, while the "my" role of a partner link represents an interface to the BPEL process. Each BPEL service must declare appropriate ports for each of these roles. Each my role must have a corresponding exported port declaration, while each partner role must have a corresponding imported port declaration.

The link between the ports and the BPEL partner-link roles is established through naming convention; a port name must take on one of the following forms:

1. partnerLink.role : the role named role of partner link named partnerlink
2. scope:partnerLink.role : the role named role of partner link named partnerLink declared in a scope named scopeName
3. scope[m]:partnerLink.role : the role named role of partner link named partnerLink declared in the m^th occurance of a scope named scopeName
4. partnerLink[n].role : the role named role of the n^th occurance of partner link named partnerLink declared anywhere in the process

If there are multiple partner links with the same name declared in a single process (as can happen when partner links are declared within a <scope>) then a form that unamigously selects a single partner link must be used. For example the following BPEL process:

<process name="HelloWorld" ....>
   <partnerLinks>
      <partnerLink name="helloPartnerLink" 
         partnerLinkType="test:HelloPartnerLinkType" 
         myRole="me" />
   </partnerLinks>
   <receive .../>
   <reply .../>       
</process>

could declare its port using the simplest (first) form:

<system-descriptor ....>
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  <services>
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    <service name="helloWorld.BpelService" provider="uri:bpelProvider">
      <exports>
        <port name="helloPartnerLink.me" type="hw:HelloPortType" ... />
      </exports>
    </service>
  </services>
</system-descriptor>

However, the BPEL process:

<process name="HelloWorld" ....>
   <partnerLinks>
      <partnerLink name="helloPartnerLink" 
         partnerLinkType="test:HelloPartnerLinkType" 
         myRole="me" />
   </partnerLinks>

   <scope>
     <partnerLinks>
       <partnerLink name="helloPartnerLink" 
          partnerLinkType="test:HelloPartnerLinkType" 
          myRole="me" />
     </partnerLinks>
     .
     .
   </scope>
</process>

would have to use one of the more precise forms; for example:

<system-descriptor ....>
  .
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  <services>
     .
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    <service name="helloWorld.BpelService" provider="uri:bpelProvider">
      <exports>
        <port name="helloPartnerLink[1].me" type="hw:HelloPortType" ... />
        <port name="helloPartnerLink[2].me" type="hw:HelloPortType" ... />
      </exports>
    </service>
  </services>
</system-descriptor>

Port-Level Properties