Extend DocumentService with the CDI Observer pattern

[rsoika]

In order to make it possible for a Plugin to have more control over the WorkflowService processing life-cycle, we can extend the existing Plugin concept with the Observer pattern.
In this extended API a plugin can register itself as a Listener to the method workflowService.processWorkitem(workitem) and can provide callback methods for the following processing phases:

• afterRegistration - called immediately after the plugin registration phase was completed
• beforeProcess - called before the method workflowkernel.process(workitem) is called and the workitem is completely prepared for processing.
• afterProcess - called immediately after the method workflowkernel.process(workitem) was called and before the method _documentService.save(workitem) is called.

[rsoika]

See Documentation at:

http://www.imixs.org/doc/engine/documentservice.html#CDI_Events