EventTarget


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 typeThe event type for which the user is registering
40       * @param listenerThe <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 useCaptureIf 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 typeSpecifies the event type of the <code>EventListener</code> 
65       *   being removed. 
66       * @param listenerThe <code>EventListener</code> parameter indicates the 
67       *   <code>EventListener </code> to be removed. 
68       * @param useCaptureSpecifies 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 evtSpecifies 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
A to Z: JavaDoc & Examples Daily Java News & Articles Open Source Projects Open Source Codes Free Computer Books Remove Frame
Popular Tags