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
entry= (Entry) fList.get(i);
					if (entry.fPosition.equals(position)) {
						fAnchor= i;
						return entry.fValue;
					}
				}
				
				
				for (int i= 0; i < fAnchor; i++) {
					entry= (Entry) fList.get(i);
					if (entry.fPosition.equals(position)) {
						fAnchor= i;
						return entry.fValue;
					}
				}
				
				return null;
			}
			
			private int getIndex(Position position) {
				Entry entry;
				int length= fList.size();
				for (int i= 0; i < length; i++) {
					entry= (Entry) fList.get(i);
					if (entry.fPosition.equals(position))
						return i;
				}
				return -1;
			}