net.sourceforge.phpeclipse/src/net/sourceforge/phpdt/internal/ui/viewsupport/SelectionListenerWithASTManager.java

   1 /*******************************************************************************
   2  * Copyright (c) 2000, 2005 IBM Corporation and others.
   3  * All rights reserved. This program and the accompanying materials
   4  * are made available under the terms of the Eclipse Public License v1.0
   5  * which accompanies this distribution, and is available at
   6  * http://www.eclipse.org/legal/epl-v10.html
   7  *
   8  * Contributors:
   9  *     IBM Corporation - initial API and implementation
  10  *******************************************************************************/
  11 package net.sourceforge.phpdt.internal.ui.viewsupport;
  12
  13 import java.util.HashMap;
  14 import java.util.Map;
  15
  16 import org.eclipse.core.runtime.IProgressMonitor;
  17 import org.eclipse.core.runtime.IStatus;
  18 import org.eclipse.core.runtime.NullProgressMonitor;
  19 import org.eclipse.core.runtime.OperationCanceledException;
  20 import org.eclipse.core.runtime.Status;
  21 import org.eclipse.core.runtime.jobs.Job;
  22 import org.eclipse.jface.text.ITextSelection;
  23 //incastrix
  24 //import org.eclipse.jface.util.ListenerList;
  25 import org.eclipse.core.runtime.ListenerList;
  26 import org.eclipse.jface.viewers.IPostSelectionProvider;
  27 import org.eclipse.jface.viewers.ISelection;
  28 import org.eclipse.jface.viewers.ISelectionChangedListener;
  29 import org.eclipse.jface.viewers.ISelectionProvider;
  30 import org.eclipse.jface.viewers.SelectionChangedEvent;
  31 import org.eclipse.ui.texteditor.ITextEditor;
  32
  33 /**
  34  * Infrastructure to share an AST for editor post selection listeners.
  35  */
  36 public class SelectionListenerWithASTManager {
  37
  38         private static SelectionListenerWithASTManager fgDefault;
  39
  40         /**
  41          * @return Returns the default manager instance.
  42          */
  43         public static SelectionListenerWithASTManager getDefault() {
  44                 if (fgDefault == null) {
  45                         fgDefault = new SelectionListenerWithASTManager();
  46                 }
  47                 return fgDefault;
  48         }
  49
  50         private final static class PartListenerGroup {
  51                 private ITextEditor fPart;
  52
  53                 private ISelectionChangedListener fSelectionListener,
  54                                 fPostSelectionListener;
  55
  56                 private Job fCurrentJob;
  57
  58                 private ListenerList fAstListeners;
  59
  60                 /**
  61                  * Lock to avoid having more than one calculateAndInform job in
  62                  * parallel. Only jobs may synchronize on this as otherwise deadlocks
  63                  * are possible.
  64                  */
  65                 private final Object fJobLock = new Object();
  66
  67                 public PartListenerGroup(ITextEditor part) {
  68                         fPart = part;
  69                         fCurrentJob = null;
  70                         fAstListeners = new ListenerList();
  71
  72                         fSelectionListener = new ISelectionChangedListener() {
  73                                 public void selectionChanged(SelectionChangedEvent event) {
  74                                         ISelection selection = event.getSelection();
  75                                         if (selection instanceof ITextSelection) {
  76                                                 fireSelectionChanged((ITextSelection) selection);
  77                                         }
  78                                 }
  79                         };
  80
  81                         fPostSelectionListener = new ISelectionChangedListener() {
  82                                 public void selectionChanged(SelectionChangedEvent event) {
  83                                         ISelection selection = event.getSelection();
  84                                         if (selection instanceof ITextSelection) {
  85                                                 firePostSelectionChanged((ITextSelection) selection);
  86                                         }
  87                                 }
  88                         };
  89                 }
  90
  91                 public boolean isEmpty() {
  92                         return fAstListeners.isEmpty();
  93                 }
  94
  95                 public void install(ISelectionListenerWithAST listener) {
  96                         if (isEmpty()) {
  97                                 ISelectionProvider selectionProvider = fPart
  98                                                 .getSelectionProvider();
  99                                 if (selectionProvider instanceof IPostSelectionProvider) {
 100                                         ((IPostSelectionProvider) selectionProvider)
 101                                                         .addPostSelectionChangedListener(fPostSelectionListener);
 102                                         selectionProvider
 103                                                         .addSelectionChangedListener(fSelectionListener);
 104                                 }
 105                         }
 106                         fAstListeners.add(listener);
 107                 }
 108
 109                 public void uninstall(ISelectionListenerWithAST listener) {
 110                         fAstListeners.remove(listener);
 111                         if (isEmpty()) {
 112                                 ISelectionProvider selectionProvider = fPart
 113                                                 .getSelectionProvider();
 114                                 if (selectionProvider instanceof IPostSelectionProvider) {
 115                                         ((IPostSelectionProvider) selectionProvider)
 116                                                         .removePostSelectionChangedListener(fPostSelectionListener);
 117                                         selectionProvider
 118                                                         .removeSelectionChangedListener(fSelectionListener);
 119                                 }
 120                         }
 121                 }
 122
 123                 public void fireSelectionChanged(final ITextSelection selection) {
 124                         if (fCurrentJob != null) {
 125                                 fCurrentJob.cancel();
 126                         }
 127                 }
 128
 129                 public void firePostSelectionChanged(final ITextSelection selection) {
 130                         if (fCurrentJob != null) {
 131                                 fCurrentJob.cancel();
 132                         }
 133
 134                         fCurrentJob = new Job("SelectionListenerWithASTManager Job") {// JavaUIMessages.SelectionListenerWithASTManager_job_title)
 135                                                                                                                                                         // {
 136                                 public IStatus run(IProgressMonitor monitor) {
 137                                         if (monitor == null) {
 138                                                 monitor = new NullProgressMonitor();
 139                                         }
 140                                         synchronized (fJobLock) {
 141                                                 return calculateASTandInform(/*input,*/ selection, monitor);
 142                                         }
 143                                 }
 144                         };
 145                         fCurrentJob.setPriority(Job.DECORATE);
 146                         fCurrentJob.setSystem(true);
 147                         fCurrentJob.schedule();
 148                 }
 149
 150                 protected IStatus calculateASTandInform(/*IJavaElement input,*/
 151                                 ITextSelection selection, IProgressMonitor monitor) {
 152                         if (monitor.isCanceled()) {
 153                                 return Status.CANCEL_STATUS;
 154                         }
 155                         // create AST
 156                         try {
 157                                 // CompilationUnit astRoot=
 158                                 // PHPeclipsePlugin.getDefault().getASTProvider().getAST(input,
 159                                 // ASTProvider.WAIT_ACTIVE_ONLY, monitor);
 160
 161                                 // if (astRoot != null && !monitor.isCanceled()) {
 162                                 Object[] listeners;
 163                                 synchronized (PartListenerGroup.this) {
 164                                         listeners = fAstListeners.getListeners();
 165                                 }
 166                                 for (int i = 0; i < listeners.length; i++) {
 167                                         ((ISelectionListenerWithAST) listeners[i])
 168                                                         .selectionChanged(fPart, selection);// , astRoot);
 169                                         if (monitor.isCanceled()) {
 170                                                 return Status.CANCEL_STATUS;
 171                                         }
 172                                 }
 173                                 return Status.OK_STATUS;
 174                                 // }
 175                         } catch (OperationCanceledException e) {
 176                                 // thrown when cancelling the AST creation
 177                         }
 178                         return Status.CANCEL_STATUS;
 179                 }
 180         }
 181
 182         private Map fListenerGroups;
 183
 184         private SelectionListenerWithASTManager() {
 185                 fListenerGroups = new HashMap();
 186         }
 187
 188         /**
 189          * Registers a selection listener for the given editor part.
 190          *
 191          * @param part
 192          *            The editor part to listen to.
 193          * @param listener
 194          *            The listener to register.
 195          */
 196         public void addListener(ITextEditor part, ISelectionListenerWithAST listener) {
 197                 synchronized (this) {
 198                         PartListenerGroup partListener = (PartListenerGroup) fListenerGroups
 199                                         .get(part);
 200                         if (partListener == null) {
 201                                 partListener = new PartListenerGroup(part);
 202                                 fListenerGroups.put(part, partListener);
 203                         }
 204                         partListener.install(listener);
 205                 }
 206         }
 207
 208         /**
 209          * Unregisters a selection listener.
 210          *
 211          * @param part
 212          *            The editor part the listener was registered.
 213          * @param listener
 214          *            The listener to unregister.
 215          */
 216         public void removeListener(ITextEditor part,
 217                         ISelectionListenerWithAST listener) {
 218                 synchronized (this) {
 219                         PartListenerGroup partListener = (PartListenerGroup) fListenerGroups
 220                                         .get(part);
 221                         if (partListener != null) {
 222                                 partListener.uninstall(listener);
 223                                 if (partListener.isEmpty()) {
 224                                         fListenerGroups.remove(part);
 225                                 }
 226                         }
 227                 }
 228         }
 229
 230         /**
 231          * Forces a selection changed event that is sent to all listeners registered
 232          * to the given editor part. The event is sent from a background thread:
 233          * this method call can return before the listeners are informed.
 234          *
 235          * @param part
 236          *            The editor part that has a changed selection
 237          * @param selection
 238          *            The new text selection
 239          */
 240         public void forceSelectionChange(ITextEditor part, ITextSelection selection) {
 241                 synchronized (this) {
 242                         PartListenerGroup partListener = (PartListenerGroup) fListenerGroups
 243                                         .get(part);
 244                         if (partListener != null) {
 245                                 partListener.firePostSelectionChanged(selection);
 246                         }
 247                 }
 248         }
 249 }