Structural comparison of two ASTs in Eclipse

Question

I am working on an incremental builder for Java code in Eclipse. Eclipse provides a ResourceDelta that tells me which resources have changed since the last build. However, I would like to have more detailed information, e.g. what methods or what field definitions changed. There seems to be functionality similar to what I want in the "compare with -> each other" view. However, this code is quite disconnected from the build engine and seems incompatible with ResourceDeltas. What would be a good way to figure out what I want? The best solution I can see is to compare two ASTs, but I also could not find any built-in support for that.

Answer 1

JavaCore does supply this information via the IElementChangedListener and IJavaElementDelta interfaces. Here's a quick code sample to get you started:

JavaCore.addElementChangedListener(new MyJavaElementChangeReporter(), ElementChangedEvent.POST_RECONCILE);

More details available in Manipulating Java code from the JDT Plug-in Developer Guide.