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 * This file is available under and governed by the GNU General Public
 * License version 2 only, as published by the Free Software Foundation.
 * However, the following notice accompanied the original version of this
 * file and, per its terms, should not be removed:
 *
 * Copyright (c) 2000 World Wide Web Consortium,
 * (Massachusetts Institute of Technology, Institut National de
 * Recherche en Informatique et en Automatique, Keio University). All
 * Rights Reserved. This program is distributed under the W3C's Software
 * Intellectual Property License. This program is distributed in the
 * hope that it will be useful, but WITHOUT ANY WARRANTY; without even
 * the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
 * PURPOSE.
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package org.w3c.dom.events;


 The EventTarget interface is implemented by all
Nodes in an implementation which supports the DOM Event
Model. Therefore, this interface can be obtained by using
binding-specific casting methods on an instance of the Node
interface. The interface allows registration and removal of
EventListeners on an EventTarget and dispatch
of events to that EventTarget.

See also the Document Object Model (DOM) Level 2 Events Specification.

Since:1.5, DOM Level 2
/**
 *  The <code>EventTarget</code> interface is implemented by all
 * <code>Nodes</code> in an implementation which supports the DOM Event
 * Model. Therefore, this interface can be obtained by using
 * binding-specific casting methods on an instance of the <code>Node</code>
 * interface. The interface allows registration and removal of
 * <code>EventListeners</code> on an <code>EventTarget</code> and dispatch
 * of events to that <code>EventTarget</code>.
 * <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>.
 * @since 1.5, DOM Level 2
 */
public interface EventTarget {
    
This method allows the registration of event listeners on the event
target. If an EventListener is added to an
EventTarget while it is processing an event, it will not
be triggered by the current actions but may be triggered during a
later stage of event flow, such as the bubbling phase.

 If multiple identical EventListeners are registered
on the same EventTarget with the same parameters the
duplicate instances are discarded. They do not cause the
EventListener to be called twice and since they are
discarded they do not need to be removed with the
removeEventListener method.

Params:
  • type – The event type for which the user is registering
  • listener – The listener parameter takes an interface
  implemented by the user which contains the methods to be called
  when the event occurs.
  • useCapture – If true, useCapture indicates that the
  user wishes to initiate capture. After initiating capture, all
  events of the specified type will be dispatched to the registered
  EventListener before being dispatched to any
  EventTargets beneath them in the tree. Events which
  are bubbling upward through the tree will not trigger an
  EventListener designated to use capture.
/**
     * This method allows the registration of event listeners on the event
     * target. If an <code>EventListener</code> is added to an
     * <code>EventTarget</code> while it is processing an event, it will not
     * be triggered by the current actions but may be triggered during a
     * later stage of event flow, such as the bubbling phase.
     * <br> If multiple identical <code>EventListener</code>s are registered
     * on the same <code>EventTarget</code> with the same parameters the
     * duplicate instances are discarded. They do not cause the
     * <code>EventListener</code> to be called twice and since they are
     * discarded they do not need to be removed with the
     * <code>removeEventListener</code> method.
     * @param type The event type for which the user is registering
     * @param listener The <code>listener</code> parameter takes an interface
     *   implemented by the user which contains the methods to be called
     *   when the event occurs.
     * @param useCapture If true, <code>useCapture</code> indicates that the
     *   user wishes to initiate capture. After initiating capture, all
     *   events of the specified type will be dispatched to the registered
     *   <code>EventListener</code> before being dispatched to any
     *   <code>EventTargets</code> beneath them in the tree. Events which
     *   are bubbling upward through the tree will not trigger an
     *   <code>EventListener</code> designated to use capture.
     */
    public void addEventListener(String type,
                                 EventListener listener,
                                 boolean useCapture);

    
This method allows the removal of event listeners from the event
target. If an EventListener is removed from an
EventTarget while it is processing an event, it will not
be triggered by the current actions. EventListeners can
never be invoked after being removed.

Calling removeEventListener with arguments which do
not identify any currently registered EventListener on
the EventTarget has no effect.

Params:
  • type – Specifies the event type of the EventListener
  being removed.
  • listener – The EventListener parameter indicates the
  EventListener  to be removed.
  • useCapture – Specifies whether the EventListener
  being removed was registered as a capturing listener or not. If a
  listener was registered twice, one with capture and one without,
  each must be removed separately. Removal of a capturing listener
  does not affect a non-capturing version of the same listener, and
  vice versa.
/**
     * This method allows the removal of event listeners from the event
     * target. If an <code>EventListener</code> is removed from an
     * <code>EventTarget</code> while it is processing an event, it will not
     * be triggered by the current actions. <code>EventListener</code>s can
     * never be invoked after being removed.
     * <br>Calling <code>removeEventListener</code> with arguments which do
     * not identify any currently registered <code>EventListener</code> on
     * the <code>EventTarget</code> has no effect.
     * @param type Specifies the event type of the <code>EventListener</code>
     *   being removed.
     * @param listener The <code>EventListener</code> parameter indicates the
     *   <code>EventListener </code> to be removed.
     * @param useCapture Specifies whether the <code>EventListener</code>
     *   being removed was registered as a capturing listener or not. If a
     *   listener was registered twice, one with capture and one without,
     *   each must be removed separately. Removal of a capturing listener
     *   does not affect a non-capturing version of the same listener, and
     *   vice versa.
     */
    public void removeEventListener(String type,
                                    EventListener listener,
                                    boolean useCapture);

    
This method allows the dispatch of events into the implementations
event model. Events dispatched in this manner will have the same
capturing and bubbling behavior as events dispatched directly by the
implementation. The target of the event is the
 EventTarget on which dispatchEvent is
called.

Params:
  • evt – Specifies the event type, behavior, and contextual
  information to be used in processing the event.
Throws:
  • EventException – 
  UNSPECIFIED_EVENT_TYPE_ERR: Raised if the Event's type
  was not specified by initializing the event before
  dispatchEvent was called. Specification of the
  Event's type as null or an empty string
  will also trigger this exception.
Returns:The return value of dispatchEvent indicates
  whether any of the listeners which handled the event called
  preventDefault. If preventDefault was
  called the value is false, else the value is true.
/**
     * This method allows the dispatch of events into the implementations
     * event model. Events dispatched in this manner will have the same
     * capturing and bubbling behavior as events dispatched directly by the
     * implementation. The target of the event is the
     * <code> EventTarget</code> on which <code>dispatchEvent</code> is
     * called.
     * @param evt Specifies the event type, behavior, and contextual
     *   information to be used in processing the event.
     * @return The return value of <code>dispatchEvent</code> indicates
     *   whether any of the listeners which handled the event called
     *   <code>preventDefault</code>. If <code>preventDefault</code> was
     *   called the value is false, else the value is true.
     * @exception EventException
     *   UNSPECIFIED_EVENT_TYPE_ERR: Raised if the <code>Event</code>'s type
     *   was not specified by initializing the event before
     *   <code>dispatchEvent</code> was called. Specification of the
     *   <code>Event</code>'s type as <code>null</code> or an empty string
     *   will also trigger this exception.
     */
    public boolean dispatchEvent(Event evt)
                                 throws EventException;

}