1 files changed, 124 insertions, 0 deletions
diff --git a/bundles/org.eclipse.compare/compare/org/eclipse/compare/BufferedContent.java b/bundles/org.eclipse.compare/compare/org/eclipse/compare/BufferedContent.java
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+++ b/bundles/org.eclipse.compare/compare/org/eclipse/compare/BufferedContent.java
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+/*
+ * Licensed Materials - Property of IBM,
+ * WebSphere Studio Workbench
+ * (c) Copyright IBM Corp 2000, 2001
+ */
+package org.eclipse.compare;
+
+import java.io.*;
+import org.eclipse.jface.util.ListenerList;
+import org.eclipse.core.runtime.CoreException;
+import org.eclipse.compare.internal.Utilities;
+
+/**
+ * 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 methods <code>getContent</code> or <code>setContent</code> is called.
+ * 
+ * @see IContentChangeNotifier
+ * @see IStreamContentAccessor
+ */
+public abstract class BufferedContent implements IContentChangeNotifier, IStreamContentAccessor {
+	
+	byte[] fContent;
+	private ListenerList fListenerList;
+	
+	/**
+	 * Creates a buffered stream content accessor.
+	 */
+	protected BufferedContent() {
+	}
+		
+	/* (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) {
+			}
+		}
+		return fContent;
+	}
+
+	/**
+	 * Discards the buffered content.
+	 */
+	public void discardBuffer() {
+		fContent= null;
+		//fireContentChanged();
+	}
+	
+	/* (non-Javadoc)
+	 * see IContentChangeNotifier.addChangeListener
+	 */
+	public void addContentChangeListener(IContentChangeListener listener) {
+		if (fListenerList == null)
+			fListenerList= new ListenerList();
+		fListenerList.add(listener);
+	}
+	
+	/* (non-Javadoc)
+	 * see IContentChangeNotifier.removeChangeListener
+	 */
+	public void removeContentChangeListener(IContentChangeListener listener) {
+		if (fListenerList != null) {
+			fListenerList.remove(listener);
+			if (fListenerList.isEmpty())
+				fListenerList= null;
+		}
+	}
+	
+	/**
+	 * Notifies all registered <code>IContentChangeListener</code>s of a content change.
+	 */
+	protected void fireContentChanged() {
+		if (fListenerList != null) {
+			Object[] listeners= fListenerList.getListeners();
+			for (int i= 0; i < listeners.length; i++)
+				((IContentChangeListener)listeners[i]).contentChanged(this);
+		}
+	}
+}
+