1 /* 2 * Copyright (c) 2000 World Wide Web Consortium, 3 * (Massachusetts Institute of Technology, Institut National de 4 * Recherche en Informatique et en Automatique, Keio University). All 5 * Rights Reserved. This program is distributed under the W3C's Software 6 * Intellectual Property License. This program is distributed in the 7 * hope that it will be useful, but WITHOUT ANY WARRANTY; without even 8 * the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR 9 * PURPOSE. 10 * See W3C License http://www.w3.org/Consortium/Legal/ for more details. 11 */ 12 13 package org.w3c.dom.events; 14 15 /** 16 * The <code>EventTarget</code> interface is implemented by all 17 * <code>Nodes</code> in an implementation which supports the DOM Event 18 * Model. Therefore, this interface can be obtained by using 19 * binding-specific casting methods on an instance of the <code>Node</code> 20 * interface. The interface allows registration and removal of 21 * <code>EventListeners</code> on an <code>EventTarget</code> and dispatch 22 * of events to that <code>EventTarget</code>. 23 * <p>See also the <a href='http://www.w3.org/TR/2000/REC-DOM-Level-2-Events-20001113'>Document Object Model (DOM) Level 2 Events Specification</a>. 24 * @since DOM Level 2 25 */ 26 public interface EventTarget { 27 /** 28 * This method allows the registration of event listeners on the event 29 * target. If an <code>EventListener</code> is added to an 30 * <code>EventTarget</code> while it is processing an event, it will not 31 * be triggered by the current actions but may be triggered during a 32 * later stage of event flow, such as the bubbling phase. 33 * <br> If multiple identical <code>EventListener</code>s are registered 34 * on the same <code>EventTarget</code> with the same parameters the 35 * duplicate instances are discarded. They do not cause the 36 * <code>EventListener</code> to be called twice and since they are 37 * discarded they do not need to be removed with the 38 * <code>removeEventListener</code> method. 39 * @param type The event type for which the user is registering 40 * @param listener The <code>listener</code> parameter takes an interface 41 * implemented by the user which contains the methods to be called 42 * when the event occurs. 43 * @param useCapture If true, <code>useCapture</code> indicates that the 44 * user wishes to initiate capture. After initiating capture, all 45 * events of the specified type will be dispatched to the registered 46 * <code>EventListener</code> before being dispatched to any 47 * <code>EventTargets</code> beneath them in the tree. Events which 48 * are bubbling upward through the tree will not trigger an 49 * <code>EventListener</code> designated to use capture. 50 */ 51 public void addEventListener(String type, 52 EventListener listener, 53 boolean useCapture); 54 55 /** 56 * This method allows the removal of event listeners from the event 57 * target. If an <code>EventListener</code> is removed from an 58 * <code>EventTarget</code> while it is processing an event, it will not 59 * be triggered by the current actions. <code>EventListener</code>s can 60 * never be invoked after being removed. 61 * <br>Calling <code>removeEventListener</code> with arguments which do 62 * not identify any currently registered <code>EventListener</code> on 63 * the <code>EventTarget</code> has no effect. 64 * @param type Specifies the event type of the <code>EventListener</code> 65 * being removed. 66 * @param listener The <code>EventListener</code> parameter indicates the 67 * <code>EventListener </code> to be removed. 68 * @param useCapture Specifies whether the <code>EventListener</code> 69 * being removed was registered as a capturing listener or not. If a 70 * listener was registered twice, one with capture and one without, 71 * each must be removed separately. Removal of a capturing listener 72 * does not affect a non-capturing version of the same listener, and 73 * vice versa. 74 */ 75 public void removeEventListener(String type, 76 EventListener listener, 77 boolean useCapture); 78 79 /** 80 * This method allows the dispatch of events into the implementations 81 * event model. Events dispatched in this manner will have the same 82 * capturing and bubbling behavior as events dispatched directly by the 83 * implementation. The target of the event is the 84 * <code> EventTarget</code> on which <code>dispatchEvent</code> is 85 * called. 86 * @param evt Specifies the event type, behavior, and contextual 87 * information to be used in processing the event. 88 * @return The return value of <code>dispatchEvent</code> indicates 89 * whether any of the listeners which handled the event called 90 * <code>preventDefault</code>. If <code>preventDefault</code> was 91 * called the value is false, else the value is true. 92 * @exception EventException 93 * UNSPECIFIED_EVENT_TYPE_ERR: Raised if the <code>Event</code>'s type 94 * was not specified by initializing the event before 95 * <code>dispatchEvent</code> was called. Specification of the 96 * <code>Event</code>'s type as <code>null</code> or an empty string 97 * will also trigger this exception. 98 */ 99 public boolean dispatchEvent(Event evt) 100 throws EventException; 101 102 } 103
