| /******************************************************************************* |
| * Copyright (c) 2000, 2016 IBM Corporation and others. |
| * |
| * This program and the accompanying materials |
| * are made available under the terms of the Eclipse Public License 2.0 |
| * which accompanies this distribution, and is available at |
| * https://www.eclipse.org/legal/epl-2.0/ |
| * |
| * SPDX-License-Identifier: EPL-2.0 |
| * |
| * Contributors: |
| * IBM Corporation - initial API and implementation |
| *******************************************************************************/ |
| package org.eclipse.jdt.internal.ui.viewsupport; |
| |
| import java.util.HashMap; |
| import java.util.Iterator; |
| import java.util.Map; |
| |
| import org.eclipse.core.runtime.IProgressMonitor; |
| import org.eclipse.core.runtime.IStatus; |
| import org.eclipse.core.runtime.ListenerList; |
| import org.eclipse.core.runtime.NullProgressMonitor; |
| import org.eclipse.core.runtime.OperationCanceledException; |
| import org.eclipse.core.runtime.Status; |
| import org.eclipse.core.runtime.jobs.Job; |
| |
| import org.eclipse.jface.viewers.ISelection; |
| import org.eclipse.jface.viewers.ISelectionChangedListener; |
| import org.eclipse.jface.viewers.ISelectionProvider; |
| import org.eclipse.jface.viewers.SelectionChangedEvent; |
| |
| import org.eclipse.jface.text.ITextSelection; |
| |
| import org.eclipse.ui.ISelectionListener; |
| import org.eclipse.ui.IWorkbenchPart; |
| |
| import org.eclipse.ui.texteditor.ITextEditor; |
| |
| import org.eclipse.jdt.core.IJavaElement; |
| import org.eclipse.jdt.core.ITypeRoot; |
| import org.eclipse.jdt.core.dom.CompilationUnit; |
| import org.eclipse.jdt.core.manipulation.SharedASTProviderCore; |
| |
| import org.eclipse.jdt.internal.ui.JavaUIMessages; |
| import org.eclipse.jdt.internal.ui.javaeditor.EditorUtility; |
| |
| /** |
| * Infrastructure to share an AST for editor post selection listeners. |
| */ |
| public class SelectionListenerWithASTManager { |
| |
| private static SelectionListenerWithASTManager fgDefault; |
| |
| /** |
| * @return Returns the default manager instance. |
| */ |
| public static SelectionListenerWithASTManager getDefault() { |
| if (fgDefault == null) { |
| fgDefault= new SelectionListenerWithASTManager(); |
| } |
| return fgDefault; |
| } |
| |
| |
| private final static class PartListenerGroup { |
| private ITextEditor fPart; |
| private ISelectionListener fPostSelectionListener; |
| private ISelectionChangedListener fSelectionListener; |
| private Job fCurrentJob; |
| private ListenerList<ISelectionListenerWithAST> fAstListeners; |
| /** |
| * Lock to avoid having more than one calculateAndInform job in parallel. |
| * Only jobs may synchronize on this as otherwise deadlocks are possible. |
| */ |
| private final Object fJobLock= new Object(); |
| |
| public PartListenerGroup(ITextEditor editorPart) { |
| fPart= editorPart; |
| fCurrentJob= null; |
| fAstListeners= new ListenerList<>(ListenerList.IDENTITY); |
| |
| fSelectionListener= new ISelectionChangedListener() { |
| @Override |
| public void selectionChanged(SelectionChangedEvent event) { |
| ISelection selection= event.getSelection(); |
| if (selection instanceof ITextSelection) { |
| fireSelectionChanged((ITextSelection) selection); |
| } |
| } |
| }; |
| |
| fPostSelectionListener= new ISelectionListener() { |
| @Override |
| public void selectionChanged(IWorkbenchPart part, ISelection selection) { |
| if (part == fPart && selection instanceof ITextSelection) |
| firePostSelectionChanged((ITextSelection) selection); |
| } |
| }; |
| } |
| |
| public boolean isEmpty() { |
| return fAstListeners.isEmpty(); |
| } |
| |
| public void install(ISelectionListenerWithAST listener) { |
| if (isEmpty()) { |
| fPart.getEditorSite().getPage().addPostSelectionListener(fPostSelectionListener); |
| ISelectionProvider selectionProvider= fPart.getSelectionProvider(); |
| if (selectionProvider != null) |
| selectionProvider.addSelectionChangedListener(fSelectionListener); |
| } |
| fAstListeners.add(listener); |
| } |
| |
| public void uninstall(ISelectionListenerWithAST listener) { |
| fAstListeners.remove(listener); |
| if (isEmpty()) { |
| fPart.getEditorSite().getPage().removePostSelectionListener(fPostSelectionListener); |
| ISelectionProvider selectionProvider= fPart.getSelectionProvider(); |
| if (selectionProvider != null) |
| selectionProvider.removeSelectionChangedListener(fSelectionListener); |
| } |
| } |
| |
| /** |
| * A selection event has occurred. |
| * |
| * @param selection the selection |
| */ |
| public void fireSelectionChanged(final ITextSelection selection) { |
| if (fCurrentJob != null) { |
| fCurrentJob.cancel(); |
| } |
| } |
| |
| /** |
| * A post selection event has occurred. |
| * |
| * @param selection the selection |
| */ |
| public void firePostSelectionChanged(final ITextSelection selection) { |
| if (fCurrentJob != null) { |
| fCurrentJob.cancel(); |
| } |
| IJavaElement input= EditorUtility.getEditorInputJavaElement(fPart, false); |
| if (!(input instanceof ITypeRoot)) { |
| return; |
| } |
| final ITypeRoot typeRoot= (ITypeRoot) input; |
| |
| |
| fCurrentJob= new Job(JavaUIMessages.SelectionListenerWithASTManager_job_title) { |
| @Override |
| public IStatus run(IProgressMonitor monitor) { |
| if (monitor == null) { |
| monitor= new NullProgressMonitor(); |
| } |
| synchronized (fJobLock) { |
| return calculateASTandInform(typeRoot, selection, monitor); |
| } |
| } |
| }; |
| fCurrentJob.setPriority(Job.DECORATE); |
| fCurrentJob.setSystem(true); |
| fCurrentJob.schedule(); |
| } |
| |
| protected final IStatus calculateASTandInform(ITypeRoot input, ITextSelection selection, IProgressMonitor monitor) { |
| if (monitor.isCanceled()) { |
| return Status.CANCEL_STATUS; |
| } |
| // create AST |
| try { |
| CompilationUnit astRoot= SharedASTProviderCore.getAST(input, SharedASTProviderCore.WAIT_ACTIVE_ONLY, monitor); |
| |
| if (astRoot != null && !monitor.isCanceled()) { |
| Iterator<ISelectionListenerWithAST> listeners; |
| synchronized (PartListenerGroup.this) { // sync probably doesn't make sense here... |
| listeners= fAstListeners.iterator(); |
| } |
| while (listeners.hasNext()) { |
| ISelectionListenerWithAST listener= listeners.next(); |
| listener.selectionChanged(fPart, selection, astRoot); |
| if (monitor.isCanceled()) { |
| return Status.CANCEL_STATUS; |
| } |
| } |
| return Status.OK_STATUS; |
| } |
| } catch (OperationCanceledException e) { |
| // thrown when canceling the AST creation |
| } |
| return Status.CANCEL_STATUS; |
| } |
| } |
| |
| |
| private Map<ITextEditor, PartListenerGroup> fListenerGroups; |
| |
| private SelectionListenerWithASTManager() { |
| fListenerGroups= new HashMap<>(); |
| } |
| |
| /** |
| * Registers a selection listener for the given editor part. |
| * @param part The editor part to listen to. |
| * @param listener The listener to register. |
| */ |
| public void addListener(ITextEditor part, ISelectionListenerWithAST listener) { |
| synchronized (this) { |
| PartListenerGroup partListener= fListenerGroups.get(part); |
| if (partListener == null) { |
| partListener= new PartListenerGroup(part); |
| fListenerGroups.put(part, partListener); |
| } |
| partListener.install(listener); |
| } |
| } |
| |
| /** |
| * Unregisters a selection listener. |
| * @param part The editor part the listener was registered. |
| * @param listener The listener to unregister. |
| */ |
| public void removeListener(ITextEditor part, ISelectionListenerWithAST listener) { |
| synchronized (this) { |
| PartListenerGroup partListener= fListenerGroups.get(part); |
| if (partListener != null) { |
| partListener.uninstall(listener); |
| if (partListener.isEmpty()) { |
| fListenerGroups.remove(part); |
| } |
| } |
| } |
| } |
| } |