| /******************************************************************************* |
| * Copyright (c) 2000, 2011 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.compare; |
| |
| import java.io.ByteArrayInputStream; |
| import java.io.InputStream; |
| |
| import org.eclipse.compare.internal.ContentChangeNotifier; |
| import org.eclipse.compare.internal.Utilities; |
| import org.eclipse.core.runtime.CoreException; |
| |
| /** |
| * Abstract implementation for a buffered <code>IStreamContentAccessor</code>. |
| * <p> |
| * Subclasses must implement the <code>createStream</code> method |
| * to connect the buffered content with a streamable source (e.g., a file). |
| * <p> |
| * As long as the contents of <code>BufferedContent</code> is only retrieved as an input stream |
| * (by means of <code>getContents</code>) and the <code>BufferedContent</code> is not modified (with |
| * <code>setContent</code>) no buffering takes place. |
| * Buffering starts when either method <code>getContent</code> or <code>setContent</code> is called. |
| * |
| * @see IContentChangeNotifier |
| * @see IStreamContentAccessor |
| */ |
| public abstract class BufferedContent implements IContentChangeNotifier, IStreamContentAccessor { |
| |
| byte[] fContent; |
| private ContentChangeNotifier fChangeNotifier; |
| |
| /** |
| * Creates a buffered stream content accessor. |
| */ |
| protected BufferedContent() { |
| // empty implementation |
| } |
| |
| /* (non-Javadoc) |
| * see IStreamContentAccessor.getContents |
| */ |
| public InputStream getContents() throws CoreException { |
| if (fContent != null) |
| return new ByteArrayInputStream(fContent); |
| return createStream(); |
| } |
| |
| /** |
| * Creates and returns a stream for reading the contents. |
| * <p> |
| * Subclasses must implement this method. |
| * </p> |
| * |
| * @return the stream from which the content is read |
| * @exception CoreException if the contents could not be accessed |
| */ |
| protected abstract InputStream createStream() throws CoreException; |
| |
| /** |
| * Sets the contents. Registered content change listeners are notified. |
| * |
| * @param contents the new contents |
| */ |
| public void setContent(byte[] contents) { |
| fContent= contents; |
| fireContentChanged(); |
| } |
| |
| /** |
| * Returns the contents as an array of bytes. |
| * |
| * @return the contents as an array of bytes, or <code>null</code> if |
| * the contents could not be accessed |
| */ |
| public byte[] getContent() { |
| if (fContent == null) { |
| try { |
| InputStream is= createStream(); |
| fContent= Utilities.readBytes(is); |
| } catch(CoreException ex) { |
| // NeedWork |
| } |
| } |
| return fContent; |
| } |
| |
| /** |
| * Discards the buffered content. |
| */ |
| public void discardBuffer() { |
| fContent= null; |
| } |
| |
| /* (non-Javadoc) |
| * see IContentChangeNotifier.addChangeListener |
| */ |
| public void addContentChangeListener(IContentChangeListener listener) { |
| if (fChangeNotifier == null) |
| fChangeNotifier= new ContentChangeNotifier(this); |
| fChangeNotifier.addContentChangeListener(listener); |
| } |
| |
| /* (non-Javadoc) |
| * see IContentChangeNotifier.removeChangeListener |
| */ |
| public void removeContentChangeListener(IContentChangeListener listener) { |
| if (fChangeNotifier != null) { |
| fChangeNotifier.removeContentChangeListener(listener); |
| if (fChangeNotifier.isEmpty()) |
| fChangeNotifier= null; |
| } |
| } |
| |
| /** |
| * Notifies all registered <code>IContentChangeListener</code>s of a content change. |
| */ |
| protected void fireContentChanged() { |
| if (fChangeNotifier == null || fChangeNotifier.isEmpty()) { |
| return; |
| } |
| fChangeNotifier.fireContentChanged(); |
| } |
| } |
| |