[UIMA-5500] UIMA-AS V3: Replace dd2spring with java based DD processing

• Type: Sub-task
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Fix Version/s: 3.0.1AS
• Component/s: Async Scaleout
• Assignee: Jaroslaw Cwiklik
• Reporter: Jaroslaw Cwiklik
• Created: 19/Jul/17 17:39
• Updated: 27/Jul/17 17:53

Description

Current UIMA-AS uses dd2spring to parse DD into intermediate format (Spring Context) which is than fed into Spring Framework to instantiate components of the UIMA-AS at runtime. The dd2spring uses saxon and custom xslt stylesheet to process a DD. The xslt is quite complex and difficult to maintain. The saxon library requires that the DD is provided as a fully qualified file preventing from loading it from a classpath or datapath.
Instead of dd2spring, the UIMA-AS can use xmlbeans to parse the DD and instantiate on object model representing it. There already exists a schema for the DD in UIMA-AS from which an object model can be generated.
New java only code can than use the model to create components necessary to deploy UIMA-AS service. The wiring of components will be done in java instead of relying on Spring which hides much of this process.
The removal of dd2spring is largely an internal UIMA-AS concern and user code impact of this change should be minimal. The user no longer will have to specify Saxon nor the dd2springXsltFilePath when launching or deploying a service.