01: /**********************************************************************************
02: * $URL: https://source.sakaiproject.org/svn/memory/tags/sakai_2-4-1/memory-api/api/src/java/org/sakaiproject/memory/api/CacheRefresher.java $
03: * $Id: CacheRefresher.java 7073 2006-03-27 20:56:40Z ggolden@umich.edu $
04: ***********************************************************************************
05: *
06: * Copyright (c) 2003, 2004, 2005, 2006 The Sakai Foundation.
07: *
08: * Licensed under the Educational Community License, Version 1.0 (the "License");
09: * you may not use this file except in compliance with the License.
10: * You may obtain a copy of the License at
11: *
12: * http://www.opensource.org/licenses/ecl1.php
13: *
14: * Unless required by applicable law or agreed to in writing, software
15: * distributed under the License is distributed on an "AS IS" BASIS,
16: * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
17: * See the License for the specific language governing permissions and
18: * limitations under the License.
19: *
20: **********************************************************************************/package org.sakaiproject.memory.api;
21:
22: import org.sakaiproject.event.api.Event;
23:
24: /**
25: * <p>
26: * Utility API for classes that will refresh a cache entry when expired.
27: * </p>
28: */
29: public interface CacheRefresher {
30: /**
31: * Get a new value for this key whose value has already expired in the cache.
32: *
33: * @param key
34: * The key whose value has expired and needs to be refreshed.
35: * @param oldValue
36: * The old exipred value of the key.
37: * @param event
38: * The event which triggered this refresh.
39: * @return a new value for use in the cache for this key; if null, the entry will be removed.
40: */
41: public Object refresh(Object key, Object oldValue, Event event);
42: }
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