AccessibleTextAdapter.java

/*******************************************************************************
 * Copyright (c) 2000, 2008, 2012 IBM Corporation, Gerhardt Informatics Kft. 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
 *     Gerhardt Informatics Kft. - GEFGWT port
 *******************************************************************************/
package org.eclipse.swt.accessibility;

/**
 * This adapter class provides default implementations for the methods described
 * by the <code>AccessibleTextListener</code> interface.
 * <p>
 * Classes that wish to deal with <code>AccessibleTextEvent</code>s can extend
 * this class and override only the methods that they are interested in.
 * </p>
 * <p>
 * Note: Accessibility clients use child identifiers to specify whether they
 * want information about a control or one of its children. Child identifiers
 * are increasing integers beginning with 0. The identifier CHILDID_SELF
 * represents the control itself. When returning a child identifier to a client,
 * you may use CHILDID_NONE to indicate that no child or control has the
 * required information.
 * </p>
 * <p>
 * Note: This adapter is typically used by implementors of a custom control to
 * provide very detailed information about the control instance to accessibility
 * clients.
 * </p>
 * 
 * @see AccessibleTextListener
 * @see AccessibleTextEvent
 * @see <a href="http://www.eclipse.org/swt/">Sample code and further
 *      information</a>
 * 
 * @since 3.0
 */
public abstract class AccessibleTextAdapter implements AccessibleTextListener {

	/**
	 * Sent when an accessibility client requests the current character offset
	 * of the text caret. The default behavior is to do nothing.
	 * <p>
	 * Return the caret offset in the <code>offset</code> field of the event
	 * object.
	 * </p>
	 * 
	 * @param e
	 *            an event object containing the following fields:
	 *            <ul>
	 *            <li>childID [IN] - an identifier specifying a child of the
	 *            control</li>
	 *            <li>offset [OUT] - the current offset of the text caret</li>
	 *            </ul>
	 */
	public void getCaretOffset(AccessibleTextEvent e) {
	}

	/**
	 * Sent when an accessibility client requests the range of the current text
	 * selection. The default behavior is to do nothing.
	 * <p>
	 * Return the selection start offset and non-negative length in the
	 * <code>offset</code> and <code>length</code> fields of the event object.
	 * </p>
	 * 
	 * @param e
	 *            an event object containing the following fields:
	 *            <ul>
	 *            <li>childID [IN] - an identifier specifying a child of the
	 *            control</li>
	 *            <li>offset [OUT] - the offset of the current text selection</li>
	 *            <li>length [OUT] - the length of the current text selection</li>
	 *            </ul>
	 */
	public void getSelectionRange(AccessibleTextEvent e) {
	}
}