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Java > Open Source Codes > com > opensymphony > oscache > base > events > CacheEvent


1 /*
2  * Copyright (c) 2002-2003 by OpenSymphony
3  * All rights reserved.
4  */
5 package com.opensymphony.oscache.base.events;
6
7
8 /**
9  * The root event class for all cache events. Each subclasses of this class
10  * classifies a particular type of cache event.
11  *
12  * @author <a HREF="&#109;a&#105;&#108;&#116;&#111;:chris&#64;swebtec.&#99;&#111;&#109;">Chris Miller</a>
13  * Date: 20-May-2003
14  * Time: 15:25:02
15  */
16 public abstract class CacheEvent {
17     /**
18      * An optional tag that can be attached to the event to specify the event's origin.
19      */
20     protected String JavaDoc origin = null;
21
22     /**
23      * No-argument constructor so subtypes can easily implement <code>Serializable</code>
24      */
25     public CacheEvent() {
26     }
27
28     /**
29      * Creates a cache event object that came from the specified origin.
30      *
31      * @param origin A string that indicates where this event was fired from.
32      * This value is optional; <code>null</code> can be passed in if an
33      * origin is not required.
34      */
35     public CacheEvent(String JavaDoc origin) {
36         this.origin = origin;
37     }
38
39     /**
40      * Retrieves the origin of this event, if one was specified. This is most
41      * useful when an event handler causes another event to fire - by checking
42      * the origin the handler is able to prevent recursive events being
43      * fired.
44      */
45     public String JavaDoc getOrigin() {
46         return origin;
47     }
48 }
49
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