CloseUnrelatedProjectsAction.java :  » IDE-Eclipse » ui-ide » org » eclipse » ui » actions » Java Open Source

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/*******************************************************************************
 * Copyright (c) 2006 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.ui.actions;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import org.eclipse.core.resources.IProject;
import org.eclipse.core.resources.IResource;
import org.eclipse.core.resources.IResourceChangeEvent;
import org.eclipse.core.resources.IResourceDelta;
import org.eclipse.core.resources.ResourcesPlugin;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.ui.PlatformUI;
import org.eclipse.ui.ide.IDEActionFactory;
import org.eclipse.ui.internal.ide.IDEWorkbenchMessages;
import org.eclipse.ui.internal.ide.IIDEHelpContextIds;
import org.eclipse.ui.internal.ide.misc.DisjointSet;

/**
 * This action closes all projects that are unrelated to the selected projects. A
 * project is unrelated if it is not directly or transitively referenced by one 
 * of the selected projects, and does not directly or transitively reference
 * one of the selected projects.
 * <p>
 * This class may be instantiated; it is not intended to be subclassed.
 * </p>
 * 
 * @see IDEActionFactory#CLOSE_UNRELATED_PROJECTS
 * @since 3.3
 */
public class CloseUnrelatedProjectsAction extends CloseResourceAction {
  /**
   * The id of this action.
   */
  public static final String ID = PlatformUI.PLUGIN_ID + ".CloseUnrelatedProjectsAction"; //$NON-NLS-1$

  private final List projectsToClose = new ArrayList();

  private boolean selectionDirty = true;

  private List oldSelection = Collections.EMPTY_LIST;

  /**
   * Builds the connected component set for the input projects.
   * The result is a DisjointSet where all related projects belong
   * to the same set.
   */
  private static DisjointSet buildConnectedComponents(IProject[] projects) {
    //initially each vertex is in a set by itself
    DisjointSet set = new DisjointSet();
    for (int i = 0; i < projects.length; i++) {
      set.makeSet(projects[i]);
    }
    for (int i = 0; i < projects.length; i++) {
      try {
        IProject[] references = projects[i].getReferencedProjects();
        //each reference represents an edge in the project reference
        //digraph from projects[i] -> references[j]
        for (int j = 0; j < references.length; j++) {
          Object setOne = set.findSet(projects[i]);
          //note that referenced projects may not exist in the workspace
          Object setTwo = set.findSet(references[j]);
          //these two projects are related, so join their sets
          if (setOne != null && setTwo != null && setOne != setTwo)
            set.union(setOne, setTwo);
        }
      } catch (CoreException e) {
        //assume inaccessible projects have no references
      }
    }
    return set;
  }

  /**
   * Creates this action.
   * 
   * @param shell
   *            The shell to use for parenting any dialogs created by this
   *            action.
   */
  public CloseUnrelatedProjectsAction(Shell shell) {
    super(shell, IDEWorkbenchMessages.CloseUnrelatedProjectsAction_text);
    setId(ID);
    setToolTipText(IDEWorkbenchMessages.CloseUnrelatedProjectsAction_toolTip);
    PlatformUI.getWorkbench().getHelpSystem().setHelp(this, IIDEHelpContextIds.CLOSE_UNRELATED_PROJECTS_ACTION);
  }

  /*
   * (non-Javadoc)
   * 
   * @see org.eclipse.ui.actions.SelectionListenerAction#clearCache()
   */
  protected void clearCache() {
    super.clearCache();
    oldSelection = Collections.EMPTY_LIST;
    selectionDirty = true;
  }

  /**
   * Computes the related projects of the selection.
   */
  private void computeRelated(List selection) {
    //build the connected component set for all projects in the workspace
    DisjointSet set = buildConnectedComponents(ResourcesPlugin.getWorkspace().getRoot().getProjects());
    //remove the connected components that the selected projects are in
    for (Iterator it = selection.iterator(); it.hasNext();)
      set.removeSet(it.next());
    //the remainder of the projects in the disjoint set are unrelated to the selection
    projectsToClose.clear();
    set.toList(projectsToClose);
  }

  /*
   * (non-Javadoc)
   * 
   * @see org.eclipse.ui.actions.SelectionListenerAction#getSelectedResources()
   */
  protected List getSelectedResources() {
    if (selectionDirty) {
      List newSelection = super.getSelectedResources();
      if (!oldSelection.equals(newSelection)) {
        oldSelection = newSelection;
        computeRelated(newSelection);
      }
      selectionDirty = false;
    }
    return projectsToClose;
  }

  /**
   * Handles a resource changed event by updating the enablement
   * when projects change.
   * <p>
   * This method overrides the super-type implementation to update
   * the selection when the open state or description of any project changes.
   */
  public void resourceChanged(IResourceChangeEvent event) {
    // don't bother looking at delta if selection not applicable
    if (selectionIsOfType(IResource.PROJECT)) {
      IResourceDelta delta = event.getDelta();
      if (delta != null) {
        IResourceDelta[] projDeltas = delta.getAffectedChildren(IResourceDelta.CHANGED);
        for (int i = 0; i < projDeltas.length; ++i) {
          IResourceDelta projDelta = projDeltas[i];
          //changing either the description or the open state can affect enablement
          if ((projDelta.getFlags() & (IResourceDelta.OPEN | IResourceDelta.DESCRIPTION)) != 0) {
            selectionChanged(getStructuredSelection());
            return;
          }
        }
      }
    }
  }
}
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