Source for org.w3c.dom.events.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 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: }