Java Doc for WorkflowServiceFactory.java in  » Workflow-Engines » wfmopen-2.1.1 » de » danet » an » workflow » api » Java Source Code / Java DocumentationJava Source Code and Java Documentation

This API does not specify how a workflow service factory or workflow service should be implemented.

• If an javax.naming.InitialContext initial naming context is available, look for a a classname in java:comp/env/de.danet.an.workflow.api.WorkflowServiceFactory. The configuration for a class as workflow service factory thus looks like:

  <env-entry>
   <description>Configure the workflow service factory</description>
   <env-entry-name>de.danet.an.workflow.api.WorkflowServiceFactory</env-entry-name>
   <env-entry-type>java.lang.String</env-entry-type>
   <env-entry-value>FactoryImplementationClass</env-entry-value>
   </env-entry>

  Note that this environment entry must be inserted in the ejb-jar.xml or web.xml for every EJB resp. servlet that calls the de.danet.an.workflow.api.WorkflowServiceFactory.newInstancenewInstance method of WorkflowServiceFactory.
• Use the services API (as detailed in the JAR specification), if available, to determine the classname. The Services API will look for a classname in the file META-INF/services/de.danet.an.workflow.api.WorkflowServiceFactory. in jars available to the runtime.

This API does not specify how a workflow service factory or workflow service should be implemented. If, however, the implementation is J2EE/EJB based, the following additional rules apply to achieve common bahaviour for J2EE based implementations.

In the J2EE environment, clients usually obtain the connection to a server from a directory service represented by an javax.naming.InitialContext InitialContext instance. This instance need not be the default initial context available to the client (think of a servlet running in a servlet container that wants to access the workflow engine running in an application server on a different machine).

In an environment that uses an javax.naming.InitialContext InitialContext to obtain the connection to the server (as described above), the following ordered lookup procedure must be implemented to determine this initial context.

• If the property "javax.naming.InitialContext" has been set, use it as initial context. if property "javax.naming.InitialContext.Environment" has been set, use it to obtain the initial context (see WorkflowServiceFactory.setProperty(String,Object) setProperty .
• If a default InitialContext is available during the execution of newInstance (i.e. "new InitialContext() succeeds), and entries java:comp/env/de.danet.an.workflow.api.WorkflowService.NAMING_CONTEXT_FACTORY and java:comp/env/de.danet.an.workflow.api.WorkflowService.NAMING_CONTEXT_URL exist, use them to obtain the initial context.
• If defined, execute vendor specific procedures to obtain an initial context.
• If a default InitialContext is available during the execution of newInstance use it (i.e. do not try to obtain another initial context (this is the common situation where a servlet based client and the workflow engine run in one application server).

Valid properties generally depend on the underlying implementation. There are, however, a few exceptions.

If the workflow service implementation is based on the J2EE environment, clients derive the connection to a server from an javax.naming.InitialContextInitialContext . There are cases when the user wants or needs to override the initial context used by the workflow service implementation. It is therefore defined that setting the property "javax.naming.InitialContext" to a value of type javax.naming.ContextContext overrides any default method used by the workflow service implementation to obtain the initial context.

As an alternative, the property "javax.naming.InitialContext.Environment" may be set to a Hashtable that contains the environment to be used when creating an InitialContext.

Subsequent versions of this interface may define additional common properties. We therefore recommended to use "fully qulified" (i.e. package style) names for properties that are specific to a workflow service implementation.
Parameters:
  name - the name of the property
Parameters:
  value - the value of the property