content: /*******************************************************************************
   * Copyright (c) 2000, 2008 IBM Corporation and others.
   * All rights reserved. This program and the accompanying materials
   * are made available under the terms of the Eclipse Public License v1.0
   * which accompanies this distribution, and is available at
   * http://www.eclipse.org/legal/epl-v10.html
   *
   * Contributors:
   *     IBM Corporation - initial API and implementation
   *******************************************************************************/
  package org.eclipse.wst.jsdt.internal.ui.viewsupport;
  
  
  import java.util.HashSet;
  
  import org.eclipse.core.resources.IMarker;
  import org.eclipse.core.resources.IMarkerDelta;
  import org.eclipse.core.resources.IProject;
  import org.eclipse.core.resources.IResource;
  import org.eclipse.core.resources.IResourceChangeEvent;
  import org.eclipse.core.resources.IResourceChangeListener;
  import org.eclipse.core.resources.IResourceDelta;
  import org.eclipse.core.resources.IResourceDeltaVisitor;
  import org.eclipse.core.runtime.CoreException;
  import org.eclipse.core.runtime.ListenerList;
  import org.eclipse.jface.text.source.AnnotationModelEvent;
  import org.eclipse.jface.text.source.IAnnotationModel;
  import org.eclipse.jface.text.source.IAnnotationModelListener;
  import org.eclipse.jface.text.source.IAnnotationModelListenerExtension;
  import org.eclipse.swt.widgets.Display;
  import org.eclipse.wst.jsdt.internal.ui.JavaScriptPlugin;
  import org.eclipse.wst.jsdt.internal.ui.javaeditor.CompilationUnitAnnotationModelEvent;
  import org.eclipse.wst.jsdt.internal.ui.util.SWTUtil;
  
  /**
   * Listens to resource deltas and filters for marker changes of type IMarker.PROBLEM
   * Viewers showing error ticks should register as listener to
   * this type.
   */
  public class ProblemMarkerManager implements IResourceChangeListener, IAnnotationModelListener , IAnnotationModelListenerExtension {
  
  	/**
  	 * Visitors used to look if the element change delta contains a marker change.
  	 */
  	private static class ProjectErrorVisitor implements IResourceDeltaVisitor {
  
  		private HashSet fChangedElements; 
  		
  		public ProjectErrorVisitor(HashSet changedElements) {
  			fChangedElements= changedElements;
  		}
  			
  		public boolean visit(IResourceDelta delta) throws CoreException {
  			IResource res= delta.getResource();
  			if (res instanceof IProject && delta.getKind() == IResourceDelta.CHANGED) {
  				IProject project= (IProject) res;
  				if (!project.isAccessible()) {
  					// only track open Java projects
  					return false;
  				}
  			}
  			checkInvalidate(delta, res);
  			return true;
  		}
  		
  		private void checkInvalidate(IResourceDelta delta, IResource resource) {
  			int kind= delta.getKind();
  			if (kind == IResourceDelta.REMOVED || kind == IResourceDelta.ADDED || (kind == IResourceDelta.CHANGED && isErrorDelta(delta))) {
  				// invalidate the resource and all parents
  				while (resource.getType() != IResource.ROOT && fChangedElements.add(resource)) {
  					resource= resource.getParent();
  				}
  			} 
  		}	
  		
  		private boolean isErrorDelta(IResourceDelta delta) {	
  			if ((delta.getFlags() & IResourceDelta.MARKERS) != 0) {
  				IMarkerDelta[] markerDeltas= delta.getMarkerDeltas();
  				for (int i= 0; i < markerDeltas.length; i++) {
  					if (markerDeltas[i].isSubtypeOf(IMarker.PROBLEM)) {
  						int kind= markerDeltas[i].getKind();
  						if (kind == IResourceDelta.ADDED || kind == IResourceDelta.REMOVED)
  							return true;
  						int severity= markerDeltas[i].getAttribute(IMarker.SEVERITY, -1);
  						int newSeverity= markerDeltas[i].getMarker().getAttribute(IMarker.SEVERITY, -1);
  						if (newSeverity != severity)
  							return true; 
  					}
  				}
  			}
  			return false;
  		}
  	}
  
  	private ListenerList fListeners;
  	
  	
  	public ProblemMarkerManager() {
  		fListeners= new ListenerList();
  	}
  
  	/*
  	 * @see IResourceChangeListener#resourceChanged
  	 */	
  	public void resourceChanged(IResourceChangeEvent event) {
  		HashSet changedElements= new HashSet();
  		
  		try {
  			IResourceDelta delta= event.getDelta();
  			if (delta != null)
  				delta.accept(new ProjectErrorVisitor(changedElements));
  		} catch (CoreException e) {
  			JavaScriptPlugin.log(e.getStatus());
  		}
  
  		if (!changedElements.isEmpty()) {
  			IResource[] changes= (IResource[]) changedElements.toArray(new IResource[changedElements.size()]);
  			fireChanges(changes, true);
  		}
  	}
  	
  	/* (non-Javadoc)
  	 * @see IAnnotationModelListener#modelChanged(IAnnotationModel)
  	 */
  	public void modelChanged(IAnnotationModel model) {
  		// no action
  	}
  
  	/* (non-Javadoc)
  	 * @see IAnnotationModelListenerExtension#modelChanged(AnnotationModelEvent)
  	 */
  	public void modelChanged(AnnotationModelEvent event) {
  		if (event instanceof CompilationUnitAnnotationModelEvent) {
  			CompilationUnitAnnotationModelEvent cuEvent= (CompilationUnitAnnotationModelEvent) event;
  			if (cuEvent.includesProblemMarkerAnnotationChanges()) {
  				IResource[] changes= new IResource[] { cuEvent.getUnderlyingResource() };
  				fireChanges(changes, false);
  			}
  		}
  	}	
  	
  	
  	/**
  	 * Adds a listener for problem marker changes.
  	 */
  	public void addListener(IProblemChangedListener listener) {
  		if (fListeners.isEmpty()) { 
  			JavaScriptPlugin.getWorkspace().addResourceChangeListener(this);
  			JavaScriptPlugin.getDefault().getCompilationUnitDocumentProvider().addGlobalAnnotationModelListener(this);
  		}
  		fListeners.add(listener);
  	}
  
  	/**
  	 * Removes a <code>IProblemChangedListener</code>.
  	 */	
  	public void removeListener(IProblemChangedListener listener) {
  		fListeners.remove(listener);
  		if (fListeners.isEmpty()) {
  			JavaScriptPlugin.getWorkspace().removeResourceChangeListener(this);
  			JavaScriptPlugin.getDefault().getCompilationUnitDocumentProvider().removeGlobalAnnotationModelListener(this);
  		}
  	}
  	
  	private void fireChanges(final IResource[] changes, final boolean isMarkerChange) {
  		Display display= SWTUtil.getStandardDisplay();
  		if (display != null && !display.isDisposed()) {
  			display.asyncExec(new Runnable() {
  				public void run() {		
  					Object[] listeners= fListeners.getListeners();
  					for (int i= 0; i < listeners.length; i++) {
  						IProblemChangedListener curr= (IProblemChangedListener) listeners[i];
  						curr.problemsChanged(changes, isMarkerChange);
  					}	
  				}
  			});
  		}	
  	}
  
  }
  