org.eclipse.text.undo.DocumentUndoManagerRegistry Maven / Gradle / Ivy
The newest version!
/*******************************************************************************
* Copyright (c) 2000, 2015 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.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 connect. After that call has successfully completed
* undo manager can be obtained via getDocumentUndoManager.
* 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.
*
* The recoding of changes starts with the first {@link #connect(IDocument)}.
*
* @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 getFileBuffer
* returns the same file buffer until disconnect is called.
*
* The recoding of changes starts with the first {@link #connect(IDocument)}.
*
* @param document the document to be connected
*/
public static synchronized void connect(IDocument document) {
Assert.isNotNull(document);
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= fgFactory.get(document);
record.count--;
if (record.count == 0)
fgFactory.remove(document);
}
/**
* Returns the file buffer managed for the given location or null
* if there is no such file buffer.
*
* 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.
*
*
* @param document the document for which to get its undo manager
* @return the document undo manager or null
*/
public static synchronized IDocumentUndoManager getDocumentUndoManager(IDocument document) {
Assert.isNotNull(document);
Record record= fgFactory.get(document);
if (record == null)
return null;
return record.undoManager;
}
}