org.eclipse.jdt.core.BufferChangedEvent.java Source code

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Here is the source code for org.eclipse.jdt.core.BufferChangedEvent.java

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/*******************************************************************************
 * Copyright (c) 2000, 2010 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.jdt.core;

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>
 *
 * @see IBuffer
 * @noextend This class is not intended to be subclassed by clients.
 */
public class BufferChangedEvent extends EventObject {

    /**
     * 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;

    private static final long serialVersionUID = 655379473891745999L; // backward compatible

    /**
     * Creates a new buffer changed event indicating that the given buffer has changed.
     *
     * @param buffer the given buffer
     * @param offset the given offset
     * @param length the given length
     * @param text the given text
     */
    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) this.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;
    }
}