/*******************************************************************************
 * Copyright (c) 2000, 2003 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
 *     
 * Port to the D programming language:
 *     Jacob Carlborg <doob@me.com>
 *******************************************************************************/
module dwt.accessibility.AccessibleListener;

import dwt.accessibility.AccessibleEvent;
import dwt.dwthelper.utils;
import dwt.internal.DWTEventListener;

/**
 * Classes that implement this interface provide methods
 * that deal with the events that are generated when an
 * accessibility client sends a message to a control.
 * <p>
 * After creating an instance of a class that implements
 * this interface it can be added to a control using the
 * <code>addAccessibleListener</code> method and removed
 * using the <code>removeAccessibleListener</code> method.
 * When a client requests information, the appropriate method
 * will be invoked.
 * </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.
 * </p>
 *
 * @see AccessibleAdapter
 * @see AccessibleEvent
 * 
 * @since 2.0
 */
public interface AccessibleListener : DWTEventListener {
    
    /**
     * Sent when an accessibility client requests the name
     * of the control, or the name of a child of the control.
     * <p>
     * Return the name of the control or specified child in the
     * <code>result</code> field of the event object. Returning
     * an empty string tells the client that the control or child
     * does not have a name, and returning null tells the client
     * to use the platform name.
     * </p>
     *
     * @param e an event object containing the following fields:<ul>
     *    <li>childID [IN] - an identifier specifying the control or one of its children</li>
     *    <li>result [OUT] - the requested name string, or null</li>
     * </ul>
     */
    public void getName (AccessibleEvent e);
    
    /**
     * Sent when an accessibility client requests the help string
     * of the control, or the help string of a child of the control.
     * <p>
     * The information in this property should be similar to the help
     * provided by toolTipText. It describes what the control or child
     * does or how to use it, as opposed to getDescription, which
     * describes appearance.
     * </p><p>
     * Return the help string of the control or specified child in
     * the <code>result</code> field of the event object. Returning
     * an empty string tells the client that the control or child
     * does not have a help string, and returning null tells the
     * client to use the platform help string.
     * </p>
     *
     * @param e an event object containing the following fields:<ul>
     *    <li>childID [IN] - an identifier specifying the control or one of its children</li>
     *    <li>result [OUT] - the requested help string, or null</li>
     * </ul>
     */
    public void getHelp (AccessibleEvent e);
    
    /**
     * Sent when an accessibility client requests the keyboard shortcut
     * of the control, or the keyboard shortcut of a child of the control.
     * <p>
     * A keyboard shortcut can either be a mnemonic, or an accelerator.
     * As a general rule, if the control or child can receive keyboard focus,
     * then you should expose its mnemonic, and if it cannot receive keyboard
     * focus, then you should expose its accelerator.
     * </p><p>
     * Return the keyboard shortcut string of the control or specified child
     * in the <code>result</code> field of the event object. Returning an
     * empty string tells the client that the control or child does not
     * have a keyboard shortcut string, and returning null tells the client
     * to use the platform keyboard shortcut string.
     * </p>
     *
     * @param e an event object containing the following fields:<ul>
     *    <li>childID [IN] - an identifier specifying the control or one of its children</li>
     *    <li>result [OUT] - the requested keyboard shortcut string (example: "ALT+N"), or null</li>
     * </ul>
     */
    public void getKeyboardShortcut (AccessibleEvent e);
    
    /**
     * Sent when an accessibility client requests a description
     * of the control, or a description of a child of the control.
     * <p>
     * This is a textual description of the control or child's visual
     * appearance, which is typically only necessary if it cannot be
     * determined from other properties such as role.
     * </p><p>
     * Return the description of the control or specified child in
     * the <code>result</code> field of the event object. Returning
     * an empty string tells the client that the control or child
     * does not have a description, and returning null tells the
     * client to use the platform description.
     * </p>
     *
     * @param e an event object containing the following fields:<ul>
     *    <li>childID [IN] - an identifier specifying the control or one of its children</li>
     *    <li>result [OUT] - the requested description string, or null</li>
     * </ul>
     */
    public void getDescription (AccessibleEvent e);
}