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