001/* 002 * Copyright (c) 2000 World Wide Web Consortium, 003 * (Massachusetts Institute of Technology, Institut National de 004 * Recherche en Informatique et en Automatique, Keio University). All 005 * Rights Reserved. This program is distributed under the W3C's Software 006 * Intellectual Property License. This program is distributed in the 007 * hope that it will be useful, but WITHOUT ANY WARRANTY; without even 008 * the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR 009 * PURPOSE. 010 * See W3C License http://www.w3.org/Consortium/Legal/ for more details. 011 */ 012 013package org.w3c.dom.events; 014 015/** 016 * The <code>EventTarget</code> interface is implemented by all 017 * <code>Nodes</code> in an implementation which supports the DOM Event 018 * Model. Therefore, this interface can be obtained by using 019 * binding-specific casting methods on an instance of the <code>Node</code> 020 * interface. The interface allows registration and removal of 021 * <code>EventListeners</code> on an <code>EventTarget</code> and dispatch 022 * of events to that <code>EventTarget</code>. 023 * <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>. 024 * @since DOM Level 2 025 */ 026public interface EventTarget { 027 /** 028 * This method allows the registration of event listeners on the event 029 * target. If an <code>EventListener</code> is added to an 030 * <code>EventTarget</code> while it is processing an event, it will not 031 * be triggered by the current actions but may be triggered during a 032 * later stage of event flow, such as the bubbling phase. 033 * <br> If multiple identical <code>EventListener</code>s are registered 034 * on the same <code>EventTarget</code> with the same parameters the 035 * duplicate instances are discarded. They do not cause the 036 * <code>EventListener</code> to be called twice and since they are 037 * discarded they do not need to be removed with the 038 * <code>removeEventListener</code> method. 039 * @param typeThe event type for which the user is registering 040 * @param listenerThe <code>listener</code> parameter takes an interface 041 * implemented by the user which contains the methods to be called 042 * when the event occurs. 043 * @param useCaptureIf true, <code>useCapture</code> indicates that the 044 * user wishes to initiate capture. After initiating capture, all 045 * events of the specified type will be dispatched to the registered 046 * <code>EventListener</code> before being dispatched to any 047 * <code>EventTargets</code> beneath them in the tree. Events which 048 * are bubbling upward through the tree will not trigger an 049 * <code>EventListener</code> designated to use capture. 050 */ 051 public void addEventListener(String type, 052 EventListener listener, 053 boolean useCapture); 054 055 /** 056 * This method allows the removal of event listeners from the event 057 * target. If an <code>EventListener</code> is removed from an 058 * <code>EventTarget</code> while it is processing an event, it will not 059 * be triggered by the current actions. <code>EventListener</code>s can 060 * never be invoked after being removed. 061 * <br>Calling <code>removeEventListener</code> with arguments which do 062 * not identify any currently registered <code>EventListener</code> on 063 * the <code>EventTarget</code> has no effect. 064 * @param typeSpecifies the event type of the <code>EventListener</code> 065 * being removed. 066 * @param listenerThe <code>EventListener</code> parameter indicates the 067 * <code>EventListener </code> to be removed. 068 * @param useCaptureSpecifies whether the <code>EventListener</code> 069 * being removed was registered as a capturing listener or not. If a 070 * listener was registered twice, one with capture and one without, 071 * each must be removed separately. Removal of a capturing listener 072 * does not affect a non-capturing version of the same listener, and 073 * vice versa. 074 */ 075 public void removeEventListener(String type, 076 EventListener listener, 077 boolean useCapture); 078 079 /** 080 * This method allows the dispatch of events into the implementations 081 * event model. Events dispatched in this manner will have the same 082 * capturing and bubbling behavior as events dispatched directly by the 083 * implementation. The target of the event is the 084 * <code> EventTarget</code> on which <code>dispatchEvent</code> is 085 * called. 086 * @param evtSpecifies the event type, behavior, and contextual 087 * information to be used in processing the event. 088 * @return The return value of <code>dispatchEvent</code> indicates 089 * whether any of the listeners which handled the event called 090 * <code>preventDefault</code>. If <code>preventDefault</code> was 091 * called the value is false, else the value is true. 092 * @exception EventException 093 * UNSPECIFIED_EVENT_TYPE_ERR: Raised if the <code>Event</code>'s type 094 * was not specified by initializing the event before 095 * <code>dispatchEvent</code> was called. Specification of the 096 * <code>Event</code>'s type as <code>null</code> or an empty string 097 * will also trigger this exception. 098 */ 099 public boolean dispatchEvent(Event evt) 100 throws EventException; 101 102}