Java tutorial
/******************************************************************************* * Copyright (c) 2000, 2010 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 *******************************************************************************/ package org.eclipse.swt.accessibility; /** * This adapter class provides default implementations for the * methods described by the <code>AccessibleControlListener</code> interface. * <p> * Classes that wish to deal with <code>AccessibleControlEvent</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 AccessibleControlListener * @see AccessibleControlEvent * @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a> * * @since 1.4 */ public abstract class AccessibleControlAdapter implements AccessibleControlListener { /** * Sent when an accessibility client requests the identifier * of the control child at the specified display coordinates. * The default behavior is to do nothing. * <p> * Return the identifier of the child at display point (x, y) * in the <code>childID</code> field of the event object. * Return CHILDID_SELF if point (x, y) is in the control itself * and not in any child. Return CHILDID_NONE if point (x, y) * is not contained in either the control or any of its children. * </p> * * @param e an event object containing the following fields:<ul> * <li>x, y [IN] - the specified point in display coordinates</li> * <li>childID [Typical OUT] - the ID of the child at point, or CHILDID_SELF, or CHILDID_NONE</li> * <li>accessible [Optional OUT] - the accessible object for the control or child may be returned instead of the childID</li> * </ul> */ public void getChildAtPoint(AccessibleControlEvent e) { } /** * Sent when an accessibility client requests the location * of the control, or the location of a child of the control. * The default behavior is to do nothing. * <p> * Return a rectangle describing the location of the specified * control or child in the <code>x, y, width, and height</code> * fields of the event object. * </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>x, y, width, height [OUT] - the control or child location in display coordinates</li> * </ul> */ public void getLocation(AccessibleControlEvent e) { } /** * Sent when an accessibility client requests the accessible object * for a child of the control by index or childID, or when a client * requests the index of an accessible object in its parent. * <p> * The childID field in the event object can be one of the following:<ul> * <li>an integer child ID - return the accessible object for the specified child ID, * or null if the specified child does not have its own accessible</li> * <li>{@link ACC#CHILDID_CHILD_AT_INDEX} - return the accessible child object at the specified index, * or null if this object has no children</li> * <li>{@link ACC#CHILDID_CHILD_INDEX} - return the index of this accessible in its parent</li> * </ul></p> * * @param e an event object containing the following fields:<ul> * <li>childID [IN] - an identifier specifying a child of the control, or one of the predefined CHILDID constants</li> * <li>detail [Optional IN] - the index of the child accessible to be returned when childID = CHILDID_CHILD_AT_INDEX</li> * <li>detail [Optional OUT] - the index of this accessible in its parent when childID = CHILDID_CHILD_INDEX</li> * <li>accessible [Optional OUT] - an Accessible for the specified childID or index, or null if one does not exist</li> * </ul> */ public void getChild(AccessibleControlEvent e) { } /** * Sent when an accessibility client requests the number of * children in the control. * The default behavior is to do nothing. * <p> * Return the number of child items in the <code>detail</code> * field of the event object. * </p> * * @param e an event object containing the following fields:<ul> * <li>detail [OUT] - the number of child items in this control</li> * </ul> */ public void getChildCount(AccessibleControlEvent e) { } /** * Sent when an accessibility client requests the default action * of the control, or the default action of a child of the control. * The default behavior is to do nothing. * <p> * This string is typically a verb describing what the user does to it. * For example, a Push Button's default action is "Press", a Check Button's * is "Check" or "UnCheck", and List items have the default action "Double Click". * </p><p> * Return a string describing the default action of the specified * control or child in the <code>result</code> field of the event object. * Returning null tells the client to use the platform default action 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 default action string, or null</li> * </ul> */ public void getDefaultAction(AccessibleControlEvent e) { } /** * Sent when an accessibility client requests the identity of * the child or control that has keyboard focus. * The default behavior is to do nothing. * <p> * Return the identifier of the child that has focus in the * <code>childID</code> field of the event object. * Return CHILDID_SELF if the control itself has keyboard focus. * Return CHILDID_NONE if neither the control nor any of its children has focus. * </p> * * @param e an event object containing the following fields:<ul> * <li>childID [Typical OUT] - the ID of the child with focus, or CHILDID_SELF, or CHILDID_NONE</li> * <li>accessible [Optional OUT] - the accessible object for a child may be returned instead of its childID</li> * </ul> */ public void getFocus(AccessibleControlEvent e) { } /** * Sent when an accessibility client requests the role * of the control, or the role of a child of the control. * The default behavior is to do nothing. * <p> * Return a role constant (constant defined in ACC beginning with ROLE_) * that describes the role of the specified control or child in the * <code>detail</code> field of the event object. * </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>detail [OUT] - a role constant describing the role of the control or child</li> * </ul> */ public void getRole(AccessibleControlEvent e) { } /** * Sent when an accessibility client requests the identity of * the child or control that is currently selected. * The default behavior is to do nothing. * <p> * Return the identifier of the selected child in the * <code>childID</code> field of the event object. * Return CHILDID_SELF if the control itself is selected. * Return CHILDID_MULTIPLE if multiple children are selected, and return an array of childIDs in the <code>children</code> field. * Return CHILDID_NONE if neither the control nor any of its children are selected. * </p> * * @param e an event object containing the following fields:<ul> * <li>childID [Typical OUT] - the ID of the selected child, or CHILDID_SELF, or CHILDID_MULTIPLE, or CHILDID_NONE</li> * <li>children [Optional OUT] - the array of childIDs for the selected children if CHILDID_MULTIPLE is returned</li> * <li>accessible [Optional OUT] - the accessible object for the control or child may be returned instead of the childID</li> * </ul> */ public void getSelection(AccessibleControlEvent e) { } /** * Sent when an accessibility client requests the state * of the control, or the state of a child of the control. * The default behavior is to do nothing. * <p> * Return a state mask (mask bit constants defined in ACC beginning with STATE_) * that describes the current state of the specified control or child in the * <code>detail</code> field of the event object. * </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>detail [OUT] - a state mask describing the current state of the control or child</li> * </ul> */ public void getState(AccessibleControlEvent e) { } /** * Sent when an accessibility client requests the value * of the control, or the value of a child of the control. * The default behavior is to do nothing. * <p> * Many controls do not return a value. Examples of controls * that do are: Combo returns the text string, Text returns * its contents, ProgressBar returns a string representing a * percentage, and Tree items return a string representing * their level in the tree. * </p><p> * Return a string describing the value of the specified control * or child in the <code>result</code> field of the event object. * Returning null tells the client to use the platform value 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 value string, or null</li> * </ul> */ public void getValue(AccessibleControlEvent e) { } /** * Sent when an accessibility client requests the children, or visible children, * of the control. The default behavior is to do nothing. * <p> * Return the children as an array of childIDs or accessibles in the * <code>children</code> field of the event object. * </p> * * @param e an event object containing the following fields:<ul> * <li>detail [IN] - a flag that may have one of the following values:<ul> * <li>0 (default) - return all children</li> * <li>VISIBLE - return all visible children</li> * </ul> * <li>children [Typical OUT] - an array of childIDs</li> * <li>children [Optional OUT] - an array of accessible objects for the children may be returned instead of the childIDs</li> * </ul> */ public void getChildren(AccessibleControlEvent e) { } }