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>Event</code> interface is used to provide contextual information 
017 * about an event to the handler processing the event. An object which 
018 * implements the <code>Event</code> interface is generally passed as the 
019 * first parameter to an event handler. More specific context information is 
020 * passed to event handlers by deriving additional interfaces from 
021 * <code>Event</code> which contain information directly relating to the 
022 * type of event they accompany. These derived interfaces are also 
023 * implemented by the object passed to the event listener. 
024 * <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>.
025 * @since DOM Level 2
026 */
027public interface Event {
028    // PhaseType
029    /**
030     * The current event phase is the capturing phase.
031     */
032    public static final short CAPTURING_PHASE           = 1;
033    /**
034     * The event is currently being evaluated at the target 
035     * <code>EventTarget</code>.
036     */
037    public static final short AT_TARGET                 = 2;
038    /**
039     * The current event phase is the bubbling phase.
040     */
041    public static final short BUBBLING_PHASE            = 3;
042
043    /**
044     * The name of the event (case-insensitive). The name must be an XML name.
045     */
046    public String getType();
047
048    /**
049     * Used to indicate the <code>EventTarget</code> to which the event was 
050     * originally dispatched. 
051     */
052    public EventTarget getTarget();
053
054    /**
055     * Used to indicate the <code>EventTarget</code> whose 
056     * <code>EventListeners</code> are currently being processed. This is 
057     * particularly useful during capturing and bubbling. 
058     */
059    public EventTarget getCurrentTarget();
060
061    /**
062     * Used to indicate which phase of event flow is currently being 
063     * evaluated. 
064     */
065    public short getEventPhase();
066
067    /**
068     * Used to indicate whether or not an event is a bubbling event. If the 
069     * event can bubble the value is true, else the value is false. 
070     */
071    public boolean getBubbles();
072
073    /**
074     * Used to indicate whether or not an event can have its default action 
075     * prevented. If the default action can be prevented the value is true, 
076     * else the value is false. 
077     */
078    public boolean getCancelable();
079
080    /**
081     *  Used to specify the time (in milliseconds relative to the epoch) at 
082     * which the event was created. Due to the fact that some systems may 
083     * not provide this information the value of <code>timeStamp</code> may 
084     * be not available for all events. When not available, a value of 0 
085     * will be returned. Examples of epoch time are the time of the system 
086     * start or 0:0:0 UTC 1st January 1970. 
087     */
088    public long getTimeStamp();
089
090    /**
091     * The <code>stopPropagation</code> method is used prevent further 
092     * propagation of an event during event flow. If this method is called 
093     * by any <code>EventListener</code> the event will cease propagating 
094     * through the tree. The event will complete dispatch to all listeners 
095     * on the current <code>EventTarget</code> before event flow stops. This 
096     * method may be used during any stage of event flow.
097     */
098    public void stopPropagation();
099
100    /**
101     * If an event is cancelable, the <code>preventDefault</code> method is 
102     * used to signify that the event is to be canceled, meaning any default 
103     * action normally taken by the implementation as a result of the event 
104     * will not occur. If, during any stage of event flow, the 
105     * <code>preventDefault</code> method is called the event is canceled. 
106     * Any default action associated with the event will not occur. Calling 
107     * this method for a non-cancelable event has no effect. Once 
108     * <code>preventDefault</code> has been called it will remain in effect 
109     * throughout the remainder of the event's propagation. This method may 
110     * be used during any stage of event flow. 
111     */
112    public void preventDefault();
113
114    /**
115     * The <code>initEvent</code> method is used to initialize the value of an 
116     * <code>Event</code> created through the <code>DocumentEvent</code> 
117     * interface. This method may only be called before the 
118     * <code>Event</code> has been dispatched via the 
119     * <code>dispatchEvent</code> method, though it may be called multiple 
120     * times during that phase if necessary. If called multiple times the 
121     * final invocation takes precedence. If called from a subclass of 
122     * <code>Event</code> interface only the values specified in the 
123     * <code>initEvent</code> method are modified, all other attributes are 
124     * left unchanged.
125     * @param eventTypeArgSpecifies the event type. This type may be any 
126     *   event type currently defined in this specification or a new event 
127     *   type.. The string must be an XML name. Any new event type must not 
128     *   begin with any upper, lower, or mixed case version of the string 
129     *   "DOM". This prefix is reserved for future DOM event sets. It is 
130     *   also strongly recommended that third parties adding their own 
131     *   events use their own prefix to avoid confusion and lessen the 
132     *   probability of conflicts with other new events.
133     * @param canBubbleArgSpecifies whether or not the event can bubble.
134     * @param cancelableArgSpecifies whether or not the event's default 
135     *   action can be prevented.
136     */
137    public void initEvent(String eventTypeArg, 
138                          boolean canBubbleArg, 
139                          boolean cancelableArg);
140
141}