http://xml.apache.org/commons/components/external/: xml-commons provides an Apache-hosted set of DOM, SAX, and JAXP interfaces for use in other xml-based projects. Our hope is that we can standardize on both a common version and packaging scheme for these critical XML standards interfaces to make the lives of both our developers and users easier. The External Components portion of xml-commons contains interfaces that are defined by external standards organizations. For DOM, that's the W3C; for SAX it's David Megginson and sax.sourceforge.net; for JAXP it's Sun. 
/*
 * 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.
 * See W3C License http://www.w3.org/Consortium/Legal/ for more details.
 */

package org.w3c.dom.events;


 The EventListener interface is the primary method for 
handling events. Users implement the EventListener interface 
and register their listener on an EventTarget using the 
AddEventListener method. The users should also remove their 
EventListener from its EventTarget after they 
have completed using the listener. 

 When a Node is copied using the cloneNode 
method the EventListeners attached to the source 
Node are not attached to the copied Node. If 
the user wishes the same EventListeners to be added to the 
newly created copy the user must add them manually. 

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

Since:DOM Level 2
/**
 *  The <code>EventListener</code> interface is the primary method for 
 * handling events. Users implement the <code>EventListener</code> interface 
 * and register their listener on an <code>EventTarget</code> using the 
 * <code>AddEventListener</code> method. The users should also remove their 
 * <code>EventListener</code> from its <code>EventTarget</code> after they 
 * have completed using the listener. 
 * <p> When a <code>Node</code> is copied using the <code>cloneNode</code> 
 * method the <code>EventListener</code>s attached to the source 
 * <code>Node</code> are not attached to the copied <code>Node</code>. If 
 * the user wishes the same <code>EventListener</code>s to be added to the 
 * newly created copy the user must add them manually. 
 * <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 DOM Level 2
 */
public interface EventListener {
    
 This method is called whenever an event occurs of the type for which 
the  EventListener interface was registered. 

Params:
  • evt –  The Event contains contextual information 
  about the event. It also contains the stopPropagation 
  and preventDefault methods which are used in 
  determining the event's flow and default action.
/**
     *  This method is called whenever an event occurs of the type for which 
     * the <code> EventListener</code> interface was registered. 
     * @param evt  The <code>Event</code> contains contextual information 
     *   about the event. It also contains the <code>stopPropagation</code> 
     *   and <code>preventDefault</code> methods which are used in 
     *   determining the event's flow and default action. 
     */
    public void handleEvent(Event evt);

}