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    
013    package 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     */
027    public 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 eventTypeArg Specifies 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 canBubbleArg Specifies whether or not the event can bubble.
134         * @param cancelableArg Specifies 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    }