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 net.sourceforge.phpdt.core.IJavaElement;
  17
  18 import org.eclipse.core.runtime.IProgressMonitor;
  19 import org.eclipse.core.runtime.IStatus;
  20 import org.eclipse.core.runtime.NullProgressMonitor;
  21 import org.eclipse.core.runtime.OperationCanceledException;
  22 import org.eclipse.core.runtime.Status;
  23 import org.eclipse.core.runtime.jobs.Job;
  24 import org.eclipse.jface.text.ITextSelection;
  25 import org.eclipse.jface.util.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.IEditorInput;
  32 import org.eclipse.ui.texteditor.ITextEditor;
  33
  34 /**
  35  * Infrastructure to share an AST for editor post selection listeners.
  36  */
  37 public class SelectionListenerWithASTManager {
  38
  39         private static SelectionListenerWithASTManager fgDefault;
  40
  41         /**
  42          * @return Returns the default manager instance.
  43          */
  44         public static SelectionListenerWithASTManager getDefault() {
  45                 if (fgDefault == null) {
  46                         fgDefault = new SelectionListenerWithASTManager();
  47                 }
  48                 return fgDefault;
  49         }
  50
  51         private final static class PartListenerGroup {
  52                 private ITextEditor fPart;
  53
  54                 private ISelectionChangedListener fSelectionListener,
  55                                 fPostSelectionListener;
  56
  57                 private Job fCurrentJob;
  58
  59                 private ListenerList fAstListeners;
  60
  61                 /**
  62                  * Lock to avoid having more than one calculateAndInform job in
  63                  * parallel. Only jobs may synchronize on this as otherwise deadlocks
  64                  * are possible.
  65                  */
  66                 private final Object fJobLock = new Object();
  67
  68                 public PartListenerGroup(ITextEditor part) {
  69                         fPart = part;
  70                         fCurrentJob = null;
  71                         fAstListeners = new ListenerList();
  72
  73                         fSelectionListener = new ISelectionChangedListener() {
  74                                 public void selectionChanged(SelectionChangedEvent event) {
  75                                         ISelection selection = event.getSelection();
  76                                         if (selection instanceof ITextSelection) {
  77                                                 fireSelectionChanged((ITextSelection) selection);
  78                                         }
  79                                 }
  80                         };
  81
  82                         fPostSelectionListener = new ISelectionChangedListener() {
  83                                 public void selectionChanged(SelectionChangedEvent event) {
  84                                         ISelection selection = event.getSelection();
  85                                         if (selection instanceof ITextSelection) {
  86                                                 firePostSelectionChanged((ITextSelection) selection);
  87                                         }
  88                                 }
  89                         };
  90                 }
  91
  92                 public boolean isEmpty() {
  93                         return fAstListeners.isEmpty();
  94                 }
  95
  96                 public void install(ISelectionListenerWithAST listener) {
  97                         if (isEmpty()) {
  98                                 ISelectionProvider selectionProvider = fPart
  99                                                 .getSelectionProvider();
 100                                 if (selectionProvider instanceof IPostSelectionProvider) {
 101                                         ((IPostSelectionProvider) selectionProvider)
 102                                                         .addPostSelectionChangedListener(fPostSelectionListener);
 103                                         selectionProvider
 104                                                         .addSelectionChangedListener(fSelectionListener);
 105                                 }
 106                         }
 107                         fAstListeners.add(listener);
 108                 }
 109
 110                 public void uninstall(ISelectionListenerWithAST listener) {
 111                         fAstListeners.remove(listener);
 112                         if (isEmpty()) {
 113                                 ISelectionProvider selectionProvider = fPart
 114                                                 .getSelectionProvider();
 115                                 if (selectionProvider instanceof IPostSelectionProvider) {
 116                                         ((IPostSelectionProvider) selectionProvider)
 117                                                         .removePostSelectionChangedListener(fPostSelectionListener);
 118                                         selectionProvider
 119                                                         .removeSelectionChangedListener(fSelectionListener);
 120                                 }
 121                         }
 122                 }
 123
 124                 public void fireSelectionChanged(final ITextSelection selection) {
 125                         if (fCurrentJob != null) {
 126                                 fCurrentJob.cancel();
 127                         }
 128                 }
 129
 130                 public void firePostSelectionChanged(final ITextSelection selection) {
 131                         if (fCurrentJob != null) {
 132                                 fCurrentJob.cancel();
 133                         }
 134                         final IJavaElement input = getJavaElement();
 135                         if (input == null) {
 136                                 return;
 137                         }
 138
 139                         fCurrentJob = new Job("SelectionListenerWithASTManager Job") {// JavaUIMessages.SelectionListenerWithASTManager_job_title)
 140                                                                                                                                                         // {
 141                                 public IStatus run(IProgressMonitor monitor) {
 142                                         if (monitor == null) {
 143                                                 monitor = new NullProgressMonitor();
 144                                         }
 145                                         synchronized (fJobLock) {
 146                                                 return calculateASTandInform(input, selection, monitor);
 147                                         }
 148                                 }
 149                         };
 150                         fCurrentJob.setPriority(Job.DECORATE);
 151                         fCurrentJob.setSystem(true);
 152                         fCurrentJob.schedule();
 153                 }
 154
 155                 private IJavaElement getJavaElement() {
 156                         IEditorInput editorInput = fPart.getEditorInput();
 157                         if (editorInput != null)
 158                                 return (IJavaElement) editorInput
 159                                                 .getAdapter(IJavaElement.class);
 160
 161                         return null;
 162                 }
 163
 164                 protected IStatus calculateASTandInform(IJavaElement input,
 165                                 ITextSelection selection, IProgressMonitor monitor) {
 166                         if (monitor.isCanceled()) {
 167                                 return Status.CANCEL_STATUS;
 168                         }
 169                         // create AST
 170                         try {
 171                                 // CompilationUnit astRoot=
 172                                 // PHPeclipsePlugin.getDefault().getASTProvider().getAST(input,
 173                                 // ASTProvider.WAIT_ACTIVE_ONLY, monitor);
 174
 175                                 // if (astRoot != null && !monitor.isCanceled()) {
 176                                 Object[] listeners;
 177                                 synchronized (PartListenerGroup.this) {
 178                                         listeners = fAstListeners.getListeners();
 179                                 }
 180                                 for (int i = 0; i < listeners.length; i++) {
 181                                         ((ISelectionListenerWithAST) listeners[i])
 182                                                         .selectionChanged(fPart, selection);// , astRoot);
 183                                         if (monitor.isCanceled()) {
 184                                                 return Status.CANCEL_STATUS;
 185                                         }
 186                                 }
 187                                 return Status.OK_STATUS;
 188                                 // }
 189                         } catch (OperationCanceledException e) {
 190                                 // thrown when cancelling the AST creation
 191                         }
 192                         return Status.CANCEL_STATUS;
 193                 }
 194         }
 195
 196         private Map fListenerGroups;
 197
 198         private SelectionListenerWithASTManager() {
 199                 fListenerGroups = new HashMap();
 200         }
 201
 202         /**
 203          * Registers a selection listener for the given editor part.
 204          *
 205          * @param part
 206          *            The editor part to listen to.
 207          * @param listener
 208          *            The listener to register.
 209          */
 210         public void addListener(ITextEditor part, ISelectionListenerWithAST listener) {
 211                 synchronized (this) {
 212                         PartListenerGroup partListener = (PartListenerGroup) fListenerGroups
 213                                         .get(part);
 214                         if (partListener == null) {
 215                                 partListener = new PartListenerGroup(part);
 216                                 fListenerGroups.put(part, partListener);
 217                         }
 218                         partListener.install(listener);
 219                 }
 220         }
 221
 222         /**
 223          * Unregisters a selection listener.
 224          *
 225          * @param part
 226          *            The editor part the listener was registered.
 227          * @param listener
 228          *            The listener to unregister.
 229          */
 230         public void removeListener(ITextEditor part,
 231                         ISelectionListenerWithAST listener) {
 232                 synchronized (this) {
 233                         PartListenerGroup partListener = (PartListenerGroup) fListenerGroups
 234                                         .get(part);
 235                         if (partListener != null) {
 236                                 partListener.uninstall(listener);
 237                                 if (partListener.isEmpty()) {
 238                                         fListenerGroups.remove(part);
 239                                 }
 240                         }
 241                 }
 242         }
 243
 244         /**
 245          * Forces a selection changed event that is sent to all listeners registered
 246          * to the given editor part. The event is sent from a background thread:
 247          * this method call can return before the listeners are informed.
 248          *
 249          * @param part
 250          *            The editor part that has a changed selection
 251          * @param selection
 252          *            The new text selection
 253          */
 254         public void forceSelectionChange(ITextEditor part, ITextSelection selection) {
 255                 synchronized (this) {
 256                         PartListenerGroup partListener = (PartListenerGroup) fListenerGroups
 257                                         .get(part);
 258                         if (partListener != null) {
 259                                 partListener.firePostSelectionChanged(selection);
 260                         }
 261                 }
 262         }
 263 }