001: /*
002: * The contents of this file are subject to the Sapient Public License
003: * Version 1.0 (the "License"); you may not use this file except in compliance
004: * with the License. You may obtain a copy of the License at
005: * http://carbon.sf.net/License.html.
006: *
007: * Software distributed under the License is distributed on an "AS IS" basis,
008: * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for
009: * the specific language governing rights and limitations under the License.
010: *
011: * The Original Code is The Carbon Component Framework.
012: *
013: * The Initial Developer of the Original Code is Sapient Corporation
014: *
015: * Copyright (C) 2003 Sapient Corporation. All Rights Reserved.
016: */
017:
018: package org.sape.carbon.services.cache.total;
019:
020: import java.util.Collections;
021: import java.util.HashMap;
022: import java.util.Map;
023:
024: import org.sape.carbon.core.component.Component;
025: import org.sape.carbon.core.component.ComponentConfiguration;
026: import org.sape.carbon.core.component.lifecycle.Configurable;
027: import org.sape.carbon.core.component.lifecycle.Initializable;
028: import org.sape.carbon.services.cache.CacheLoadException;
029:
030: import org.apache.commons.logging.Log;
031: import org.apache.commons.logging.LogFactory;
032:
033: /**
034: * <p>The Total Cache implementation of the Cache interface is intended for
035: * access to data which expires periodically as a whole or which can be changed
036: * on the fly by clients.</p>
037: *
038: * <p>
039: * This implementation uses a synchronized map to store all data. This means
040: * that all gets and puts are synchronized to ensure consistent results
041: * </p>
042: *
043: * Copyright 2002 Sapient
044: * @since carbon 1.0
045: * @author Douglas Voet, March 2002
046: * @version $Revision: 1.15 $($Author: ghinkl $ / $Date: 2003/09/30 02:43:48 $)
047: */
048: public class WritableCache extends AbstractTotalCache implements
049: Configurable, Initializable {
050:
051: /** The handle to Apache-commons logger */
052: private Log log = LogFactory.getLog(this .getClass());
053:
054: /** Map of the cached values. */
055: private Map activeMap = null;
056:
057: /** Holds the dataloader for this cache. */
058: private TotalCacheDataLoader dataLoader = null;
059:
060: /**
061: * Refresh the contents of the cache. First, initialize a holding cache.
062: * Then load the holding cache with new data from the data loader. Finally,
063: * activate the holding cache.
064: *
065: * @throws CacheLoadException when its data loader has failed to load data
066: */
067: public void refreshAll() throws CacheLoadException {
068:
069: if (log.isTraceEnabled()) {
070: log.trace("Refreshing Cache");
071: }
072:
073: synchronized (this .activeMap) {
074: this .activeMap.clear();
075: this .activeMap.putAll(this .dataLoader.loadAllData());
076: }
077: }
078:
079: /**
080: * @see Configurable#configure(ComponentConfiguration)
081: */
082: public void configure(ComponentConfiguration configuration) {
083:
084: this .dataLoader = ((TotalCacheConfiguration) configuration)
085: .getDataLoader();
086: }
087:
088: /**
089: * @see Initializable#initialize(org.sape.carbon.core.component.Component)
090: */
091: public void initialize(Component this Component) throws Exception {
092:
093: Map holdingMap;
094: // Checking for instance of appropriate dataloader. This will
095: // enable backward compatibility.
096: if (this .dataLoader instanceof ConfigurableMapTypeCacheDataLoader) {
097: holdingMap = ((ConfigurableMapTypeCacheDataLoader) this .dataLoader)
098: .getMapInstance();
099: } else {
100: holdingMap = new HashMap();
101: }
102: this .activeMap = Collections.synchronizedMap(holdingMap);
103: }
104:
105: /**
106: * @see AbstractTotalCache#getCacheMap()
107: */
108: protected Map getCacheMap() {
109: return this.activeMap;
110: }
111: }
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