| /******************************************************************************* |
| * Copyright (c) 2000, 2008 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.text.undo; |
| |
| import java.util.HashMap; |
| import java.util.Map; |
| |
| import org.eclipse.core.runtime.Assert; |
| |
| import org.eclipse.jface.text.IDocument; |
| |
| |
| /** |
| * This document undo manager registry provides access to a document's |
| * undo manager. In order to connect a document a document undo manager |
| * call <code>connect</code>. After that call has successfully completed |
| * undo manager can be obtained via <code>getDocumentUndoManager</code>. |
| * The undo manager is created on the first connect and disposed on the last |
| * disconnect, i.e. this registry keeps track of how often a undo manager is |
| * connected and returns the same undo manager to each client as long as the |
| * document is connected. |
| * <p> |
| * <em>The recoding of changes starts with the first {@link #connect(IDocument)}.</em></p> |
| * |
| * @since 3.2 |
| * @noinstantiate This class is not intended to be instantiated by clients. |
| */ |
| public final class DocumentUndoManagerRegistry { |
| |
| private static final class Record { |
| public Record(IDocument document) { |
| count= 0; |
| undoManager= new DocumentUndoManager(document); |
| } |
| private int count; |
| private IDocumentUndoManager undoManager; |
| } |
| |
| private static Map fgFactory= new HashMap(); |
| |
| private DocumentUndoManagerRegistry() { |
| // Do not instantiate |
| } |
| |
| |
| /** |
| * Connects the file at the given location to this manager. After that call |
| * successfully completed it is guaranteed that each call to <code>getFileBuffer</code> |
| * returns the same file buffer until <code>disconnect</code> is called. |
| * <p> |
| * <em>The recoding of changes starts with the first {@link #connect(IDocument)}.</em></p> |
| * |
| * @param document the document to be connected |
| */ |
| public static synchronized void connect(IDocument document) { |
| Assert.isNotNull(document); |
| Record record= (Record)fgFactory.get(document); |
| if (record == null) { |
| record= new Record(document); |
| fgFactory.put(document, record); |
| } |
| record.count++; |
| } |
| |
| /** |
| * Disconnects the given document from this registry. |
| * |
| * @param document the document to be disconnected |
| */ |
| public static synchronized void disconnect(IDocument document) { |
| Assert.isNotNull(document); |
| Record record= (Record)fgFactory.get(document); |
| record.count--; |
| if (record.count == 0) |
| fgFactory.remove(document); |
| |
| } |
| |
| /** |
| * Returns the file buffer managed for the given location or <code>null</code> |
| * if there is no such file buffer. |
| * <p> |
| * The provided location is either a full path of a workspace resource or |
| * an absolute path in the local file system. The file buffer manager does |
| * not resolve the location of workspace resources in the case of linked |
| * resources. |
| * </p> |
| * |
| * @param document the document for which to get its undo manager |
| * @return the document undo manager or <code>null</code> |
| */ |
| public static synchronized IDocumentUndoManager getDocumentUndoManager(IDocument document) { |
| Assert.isNotNull(document); |
| Record record= (Record)fgFactory.get(document); |
| if (record == null) |
| return null; |
| return record.undoManager; |
| } |
| |
| } |