Bug 43766 [reconciling] ResourceMarkerAnnotationModel listener taking a long time
Build: I20030925 I was investigating a situation where adding breakpoints to a large file was very slow. It can take up to a second to add a breakpoint to a file such as Workspace.java (2000 lines). Almost all of this time is in the resource change listener added by ResourceMarkerAnnotationModel. First, a minor issue: Instead of adding a resource change listener that traverses the entire delta, you can locate a given resource delta within the resource change delta very quickly using IResourceDelta.findMember(): public void resourceChanged(IResourceChangeEvent e) { IResourceDelta delta= e.getDelta(); if (delta != null) { IResourceDelta child = delta.findMember(fResource.getFullPath()); if (child != null) update(child.getMarkerDeltas()); } } However, this was only a small speed improvement. The main problem is that the entire compilation unit is reparsed every time a breakpoint is added. I have added a profiler trace of where the time is going for adding a single breakpoint.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/filebuffers/CompilationUnitDocumentProvider2.java
private ICompilationUnit fCompilationUnit;
			private List fCollectedProblems;
			private List fGeneratedAnnotations;
			private IProgressMonitor fProgressMonitor;
			private boolean fIsActive= false;
			
			private ReverseMap fReverseMap= new ReverseMap();
			private List fPreviouslyOverlaid= null; 
			private List fCurrentlyOverlaid= new ArrayList();
			private CompilationUnitAnnotationModelEvent fCurrentEvent;
			public CompilationUnitAnnotationModel(IResource resource) {
				super(resource);
				fCurrentEvent= new CompilationUnitAnnotationModelEvent(this, getResource());
			}
			
			public void setCompilationUnit(ICompilationUnit unit)  {
				fCompilationUnit= unit;
			}
			
			protected MarkerAnnotation createMarkerAnnotation(IMarker marker) {
				return new JavaMarkerAnnotation(marker);
			}
			
			protected Position createPositionFromProblem(IProblem problem) {
				int start= problem.getSourceStart();
				if (start < 0)
					return null;