Bug 317803 [CommonNavigator] NPE in WorkingSetsContentProvider
bundles/org.eclipse.ui.navigator.resources/src/org/eclipse/ui/internal/navigator/workingsets/WorkingSetsContentProvider.java
*
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.ui.internal.navigator.workingsets;
import java.util.Map;
import java.util.WeakHashMap;
import org.eclipse.core.runtime.IAdaptable;
import org.eclipse.core.resources.IProject;
import org.eclipse.core.resources.IResource;
import org.eclipse.jface.util.IPropertyChangeListener;
import org.eclipse.jface.util.PropertyChangeEvent;
import org.eclipse.jface.viewers.Viewer;
import org.eclipse.ui.IAggregateWorkingSet;
import org.eclipse.ui.IMemento;
import org.eclipse.ui.IWorkingSet;
import org.eclipse.ui.internal.navigator.NavigatorContentService;
import org.eclipse.ui.navigator.CommonNavigator;
import org.eclipse.ui.navigator.CommonViewer;
import org.eclipse.ui.navigator.ICommonContentExtensionSite;
import org.eclipse.ui.navigator.ICommonContentProvider;
import org.eclipse.ui.navigator.IExtensionStateModel;
import org.eclipse.ui.navigator.resources.ProjectExplorer;
/**
 * Provides children and parents for IWorkingSets.
 * 
 * @since 3.2.1
 * 
 */
public class WorkingSetsContentProvider implements ICommonContentProvider {