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1   /*
2    * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
3    *
4    * This code is free software; you can redistribute it and/or modify it
5    * under the terms of the GNU General Public License version 2 only, as
6    * published by the Free Software Foundation.  Oracle designates this
7    * particular file as subject to the "Classpath" exception as provided
8    * by Oracle in the LICENSE file that accompanied this code.
9    *
10   * This code is distributed in the hope that it will be useful, but WITHOUT
11   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
13   * version 2 for more details (a copy is included in the LICENSE file that
14   * accompanied this code).
15   *
16   * You should have received a copy of the GNU General Public License version
17   * 2 along with this work; if not, write to the Free Software Foundation,
18   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19   *
20   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21   * or visit www.oracle.com if you need additional information or have any
22   * questions.
23   */
24  
25  /*
26   * This file is available under and governed by the GNU General Public
27   * License version 2 only, as published by the Free Software Foundation.
28   * However, the following notice accompanied the original version of this
29   * file and, per its terms, should not be removed:
30   *
31   * Copyright (c) 2000 World Wide Web Consortium,
32   * (Massachusetts Institute of Technology, Institut National de
33   * Recherche en Informatique et en Automatique, Keio University). All
34   * Rights Reserved. This program is distributed under the W3C's Software
35   * Intellectual Property License. This program is distributed in the
36   * hope that it will be useful, but WITHOUT ANY WARRANTY; without even
37   * the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
38   * PURPOSE.
39   * See W3C License http://www.w3.org/Consortium/Legal/ for more details.
40   */
41  
42  package org.w3c.dom.events;
43  
44  /**
45   *  The <code>EventTarget</code> interface is implemented by all
46   * <code>Nodes</code> in an implementation which supports the DOM Event
47   * Model. Therefore, this interface can be obtained by using
48   * binding-specific casting methods on an instance of the <code>Node</code>
49   * interface. The interface allows registration and removal of
50   * <code>EventListeners</code> on an <code>EventTarget</code> and dispatch
51   * of events to that <code>EventTarget</code>.
52   * <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>.
53   * @since DOM Level 2
54   */
55  public interface EventTarget {
56      /**
57       * This method allows the registration of event listeners on the event
58       * target. If an <code>EventListener</code> is added to an
59       * <code>EventTarget</code> while it is processing an event, it will not
60       * be triggered by the current actions but may be triggered during a
61       * later stage of event flow, such as the bubbling phase.
62       * <br> If multiple identical <code>EventListener</code>s are registered
63       * on the same <code>EventTarget</code> with the same parameters the
64       * duplicate instances are discarded. They do not cause the
65       * <code>EventListener</code> to be called twice and since they are
66       * discarded they do not need to be removed with the
67       * <code>removeEventListener</code> method.
68       * @param type The event type for which the user is registering
69       * @param listener The <code>listener</code> parameter takes an interface
70       *   implemented by the user which contains the methods to be called
71       *   when the event occurs.
72       * @param useCapture If true, <code>useCapture</code> indicates that the
73       *   user wishes to initiate capture. After initiating capture, all
74       *   events of the specified type will be dispatched to the registered
75       *   <code>EventListener</code> before being dispatched to any
76       *   <code>EventTargets</code> beneath them in the tree. Events which
77       *   are bubbling upward through the tree will not trigger an
78       *   <code>EventListener</code> designated to use capture.
79       */
80      public void addEventListener(String type,
81                                   EventListener listener,
82                                   boolean useCapture);
83  
84      /**
85       * This method allows the removal of event listeners from the event
86       * target. If an <code>EventListener</code> is removed from an
87       * <code>EventTarget</code> while it is processing an event, it will not
88       * be triggered by the current actions. <code>EventListener</code>s can
89       * never be invoked after being removed.
90       * <br>Calling <code>removeEventListener</code> with arguments which do
91       * not identify any currently registered <code>EventListener</code> on
92       * the <code>EventTarget</code> has no effect.
93       * @param type Specifies the event type of the <code>EventListener</code>
94       *   being removed.
95       * @param listener The <code>EventListener</code> parameter indicates the
96       *   <code>EventListener </code> to be removed.
97       * @param useCapture Specifies whether the <code>EventListener</code>
98       *   being removed was registered as a capturing listener or not. If a
99       *   listener was registered twice, one with capture and one without,
100      *   each must be removed separately. Removal of a capturing listener
101      *   does not affect a non-capturing version of the same listener, and
102      *   vice versa.
103      */
104     public void removeEventListener(String type,
105                                     EventListener listener,
106                                     boolean useCapture);
107 
108     /**
109      * This method allows the dispatch of events into the implementations
110      * event model. Events dispatched in this manner will have the same
111      * capturing and bubbling behavior as events dispatched directly by the
112      * implementation. The target of the event is the
113      * <code> EventTarget</code> on which <code>dispatchEvent</code> is
114      * called.
115      * @param evt Specifies the event type, behavior, and contextual
116      *   information to be used in processing the event.
117      * @return The return value of <code>dispatchEvent</code> indicates
118      *   whether any of the listeners which handled the event called
119      *   <code>preventDefault</code>. If <code>preventDefault</code> was
120      *   called the value is false, else the value is true.
121      * @exception EventException
122      *   UNSPECIFIED_EVENT_TYPE_ERR: Raised if the <code>Event</code>'s type
123      *   was not specified by initializing the event before
124      *   <code>dispatchEvent</code> was called. Specification of the
125      *   <code>Event</code>'s type as <code>null</code> or an empty string
126      *   will also trigger this exception.
127      */
128     public boolean dispatchEvent(Event evt)
129                                  throws EventException;
130 
131 }