/*******************************************************************************
 * Copyright (c) 2002, 2009 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:
 * Rational Software - Initial API and implementation
 *******************************************************************************/
package org.eclipse.cdt.core.model;

import java.util.EventObject;


/**
 * A   buffer changed event describes how a buffer has changed. These events are
 * used in <code>IBufferChangedListener</code> notifications.
 * <p>
 * For text insertions, <code>getOffset</code> is the offset
 * of the first inserted character, <code>getText</code> is the
 * inserted text, and <code>getLength</code> is 0.
 * </p>
 * <p>
 * For text removals, <code>getOffset</code> is the offset
 * of the first removed character, <code>getText</code> is <code>null</code>,
 * and <code>getLength</code> is the length of the text that was removed.
 * </p>
 * <p>
 * For replacements (including <code>IBuffer.setContents</code>), 
 * <code>getOffset</code> is the offset
 * of the first replaced character, <code>getText</code> is the replacement
 * text, and <code>getLength</code> is the length of the original text
 * that was replaced.
 * </p>
 * <p>
 * When a buffer is closed, <code>getOffset</code> is 0, <code>getLength</code>
 * is 0, and <code>getText</code> is <code>null</code>.
 * </p>
 * <p>
 * @noextend This class is not intended to be subclassed by clients.
 * 
 * Instances of this class are automatically created by the C model.
 * </p>
 *
 * @see IBuffer
 * This class is similar to the JDT BufferChangedEvent class. 
 */

public class BufferChangedEvent extends EventObject {
	/**
	 * Comment for <code>serialVersionUID</code>
	 */
	private static final long serialVersionUID = 3979268036526355761L;

	/**
	 * The length of text that has been modified in the buffer.
	 */
	private int length;

	/**
	 * The offset into the buffer where the modification took place.
	 */
	private int offset;

	/**
	 * The text that was modified.
	 */
	private String text;

	/**
	 * Creates a new buffer changed event indicating that the given buffer has changed.
	 */
	public BufferChangedEvent(IBuffer buffer, int offset, int length, String text) {
		super(buffer);
		this.offset = offset;
		this.length = length;
		this.text = text;
	}
	/**
	 * Returns the buffer which has changed.
	 *
	 * @return the buffer affected by the change
	 */
	public IBuffer getBuffer() {
		return (IBuffer) source;
	}
	/**
	 * Returns the length of text removed or replaced in the buffer, or
	 * 0 if text has been inserted into the buffer.
	 *
	 * @return the length of the original text fragment modified by the 
	 *   buffer change (<code> 0 </code> in case of insertion).
	 */
	public int getLength() {
		return this.length;
	}
	/**
	 * Returns the index of the first character inserted, removed, or replaced
	 * in the buffer.
	 *
	 * @return the source offset of the textual manipulation in the buffer
	 */
	public int getOffset() {
		return this.offset;
	}
	/**
	 * Returns the text that was inserted, the replacement text,
	 * or <code>null</code> if text has been removed.
	 *
	 * @return the text corresponding to the buffer change (<code> null </code>
	 *   in case of deletion).
	 */
	public String getText() {
		return this.text;
	}

}
