/*
 * 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 Event interface is used to provide contextual information 
about an event to the handler processing the event. An object which 
implements the Event interface is generally passed as the 
first parameter to an event handler. More specific context information is 
passed to event handlers by deriving additional interfaces from 
Event which contain information directly relating to the 
type of event they accompany. These derived interfaces are also 
implemented by the object passed to the event listener. 
See also the Document Object Model (DOM) Level 2 Events Specification.
Since:
DOM Level 2/**
 * The <code>Event</code> interface is used to provide contextual information 
 * about an event to the handler processing the event. An object which 
 * implements the <code>Event</code> interface is generally passed as the 
 * first parameter to an event handler. More specific context information is 
 * passed to event handlers by deriving additional interfaces from 
 * <code>Event</code> which contain information directly relating to the 
 * type of event they accompany. These derived interfaces are also 
 * implemented by the object passed to the event listener. 
 * <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 Event {
    // PhaseType
    
The current event phase is the capturing phase.
/**
     * The current event phase is the capturing phase.
     */
    public static final short CAPTURING_PHASE           = 1;
    
The event is currently being evaluated at the target 
EventTarget.
/**
     * The event is currently being evaluated at the target 
     * <code>EventTarget</code>.
     */
    public static final short AT_TARGET                 = 2;
    
The current event phase is the bubbling phase.
/**
     * The current event phase is the bubbling phase.
     */
    public static final short BUBBLING_PHASE            = 3;

    
The name of the event (case-insensitive). The name must be an XML name.
/**
     * The name of the event (case-insensitive). The name must be an XML name.
     */
    public String getType();

    
Used to indicate the EventTarget to which the event was 
originally dispatched. 
/**
     * Used to indicate the <code>EventTarget</code> to which the event was 
     * originally dispatched. 
     */
    public EventTarget getTarget();

    
Used to indicate the EventTarget whose 
EventListeners are currently being processed. This is 
particularly useful during capturing and bubbling. 
/**
     * Used to indicate the <code>EventTarget</code> whose 
     * <code>EventListeners</code> are currently being processed. This is 
     * particularly useful during capturing and bubbling. 
     */
    public EventTarget getCurrentTarget();

    
Used to indicate which phase of event flow is currently being 
evaluated. 
/**
     * Used to indicate which phase of event flow is currently being 
     * evaluated. 
     */
    public short getEventPhase();

    
Used to indicate whether or not an event is a bubbling event. If the 
event can bubble the value is true, else the value is false. 
/**
     * Used to indicate whether or not an event is a bubbling event. If the 
     * event can bubble the value is true, else the value is false. 
     */
    public boolean getBubbles();

    
Used to indicate whether or not an event can have its default action 
prevented. If the default action can be prevented the value is true, 
else the value is false. 
/**
     * Used to indicate whether or not an event can have its default action 
     * prevented. If the default action can be prevented the value is true, 
     * else the value is false. 
     */
    public boolean getCancelable();

    
 Used to specify the time (in milliseconds relative to the epoch) at 
which the event was created. Due to the fact that some systems may 
not provide this information the value of timeStamp may 
be not available for all events. When not available, a value of 0 
will be returned. Examples of epoch time are the time of the system 
start or 0:0:0 UTC 1st January 1970. 
/**
     *  Used to specify the time (in milliseconds relative to the epoch) at 
     * which the event was created. Due to the fact that some systems may 
     * not provide this information the value of <code>timeStamp</code> may 
     * be not available for all events. When not available, a value of 0 
     * will be returned. Examples of epoch time are the time of the system 
     * start or 0:0:0 UTC 1st January 1970. 
     */
    public long getTimeStamp();

    
The stopPropagation method is used prevent further 
propagation of an event during event flow. If this method is called 
by any EventListener the event will cease propagating 
through the tree. The event will complete dispatch to all listeners 
on the current EventTarget before event flow stops. This 
method may be used during any stage of event flow.
/**
     * The <code>stopPropagation</code> method is used prevent further 
     * propagation of an event during event flow. If this method is called 
     * by any <code>EventListener</code> the event will cease propagating 
     * through the tree. The event will complete dispatch to all listeners 
     * on the current <code>EventTarget</code> before event flow stops. This 
     * method may be used during any stage of event flow.
     */
    public void stopPropagation();

    
If an event is cancelable, the preventDefault method is 
used to signify that the event is to be canceled, meaning any default 
action normally taken by the implementation as a result of the event 
will not occur. If, during any stage of event flow, the 
preventDefault method is called the event is canceled. 
Any default action associated with the event will not occur. Calling 
this method for a non-cancelable event has no effect. Once 
preventDefault has been called it will remain in effect 
throughout the remainder of the event's propagation. This method may 
be used during any stage of event flow. 
/**
     * If an event is cancelable, the <code>preventDefault</code> method is 
     * used to signify that the event is to be canceled, meaning any default 
     * action normally taken by the implementation as a result of the event 
     * will not occur. If, during any stage of event flow, the 
     * <code>preventDefault</code> method is called the event is canceled. 
     * Any default action associated with the event will not occur. Calling 
     * this method for a non-cancelable event has no effect. Once 
     * <code>preventDefault</code> has been called it will remain in effect 
     * throughout the remainder of the event's propagation. This method may 
     * be used during any stage of event flow. 
     */
    public void preventDefault();

    
The initEvent method is used to initialize the value of an 
Event created through the DocumentEvent 
interface. This method may only be called before the 
Event has been dispatched via the 
dispatchEvent method, though it may be called multiple 
times during that phase if necessary. If called multiple times the 
final invocation takes precedence. If called from a subclass of 
Event interface only the values specified in the 
initEvent method are modified, all other attributes are 
left unchanged.
Params:
eventTypeArg – Specifies the event type. This type may be any 
  event type currently defined in this specification or a new event 
  type.. The string must be an XML name. Any new event type must not 
  begin with any upper, lower, or mixed case version of the string 
  "DOM". This prefix is reserved for future DOM event sets. It is 
  also strongly recommended that third parties adding their own 
  events use their own prefix to avoid confusion and lessen the 
  probability of conflicts with other new events.
canBubbleArg – Specifies whether or not the event can bubble.
cancelableArg – Specifies whether or not the event's default 
  action can be prevented./**
     * The <code>initEvent</code> method is used to initialize the value of an 
     * <code>Event</code> created through the <code>DocumentEvent</code> 
     * interface. This method may only be called before the 
     * <code>Event</code> has been dispatched via the 
     * <code>dispatchEvent</code> method, though it may be called multiple 
     * times during that phase if necessary. If called multiple times the 
     * final invocation takes precedence. If called from a subclass of 
     * <code>Event</code> interface only the values specified in the 
     * <code>initEvent</code> method are modified, all other attributes are 
     * left unchanged.
     * @param eventTypeArg Specifies the event type. This type may be any 
     *   event type currently defined in this specification or a new event 
     *   type.. The string must be an XML name. Any new event type must not 
     *   begin with any upper, lower, or mixed case version of the string 
     *   "DOM". This prefix is reserved for future DOM event sets. It is 
     *   also strongly recommended that third parties adding their own 
     *   events use their own prefix to avoid confusion and lessen the 
     *   probability of conflicts with other new events.
     * @param canBubbleArg Specifies whether or not the event can bubble.
     * @param cancelableArg Specifies whether or not the event's default 
     *   action can be prevented.
     */
    public void initEvent(String eventTypeArg, 
                          boolean canBubbleArg, 
                          boolean cancelableArg);

}