org.apache.commons.jcs.JCS.java Source code

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Here is the source code for org.apache.commons.jcs.JCS.java

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package org.apache.commons.jcs;

import java.util.Properties;

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

import org.apache.commons.jcs.access.CacheAccess;
import org.apache.commons.jcs.access.GroupCacheAccess;
import org.apache.commons.jcs.access.exception.CacheException;
import org.apache.commons.jcs.engine.behavior.ICompositeCacheAttributes;
import org.apache.commons.jcs.engine.behavior.IElementAttributes;
import org.apache.commons.jcs.engine.control.CompositeCache;
import org.apache.commons.jcs.engine.control.CompositeCacheManager;
import org.apache.commons.jcs.engine.control.group.GroupAttrName;

/**
 * Simple class for using JCS. To use JCS in your application, you can use the static methods of
 * this class to get access objects (instances of this class) for your cache regions. One CacheAccess
 * object should be created for each region you want to access. If you have several regions, then
 * get instances for each. For best performance the getInstance call should be made in an
 * initialization method.
 */
public abstract class JCS {
    /** cache.ccf alternative. */
    private static String configFilename = null;

    /** alternative configuration properties */
    private static Properties configProps = null;

    /** Cache manager use by the various forms of defineRegion and getAccess */
    private static CompositeCacheManager cacheMgr;

    /**
     * Set the filename that the cache manager will be initialized with. Only matters before the
     * instance is initialized.
     * <p>
     * @param configFilename
     */
    public static void setConfigFilename(String configFilename) {
        JCS.configFilename = configFilename;
    }

    /**
     * Set the properties that the cache manager will be initialized with. Only
     * matters before the instance is initialized.
     *
     * @param configProps
     */
    public static void setConfigProperties(Properties configProps) {
        JCS.configProps = configProps;
    }

    /**
     * Shut down the cache manager and set the instance to null
     */
    public static void shutdown() {
        synchronized (JCS.class) {
            if (cacheMgr != null && cacheMgr.isInitialized()) {
                cacheMgr.shutDown();
            }

            cacheMgr = null;
        }
    }

    /**
     * Helper method which checks to make sure the cacheMgr class field is set, and if not requests
     * an instance from CacheManagerFactory.
     *
     * @throws CacheException if the configuration cannot be loaded
     */
    private static CompositeCacheManager getCacheManager() throws CacheException {
        synchronized (JCS.class) {
            if (cacheMgr == null || !cacheMgr.isInitialized()) {
                if (configProps != null) {
                    cacheMgr = CompositeCacheManager.getUnconfiguredInstance();
                    cacheMgr.configure(configProps);
                } else if (configFilename != null) {
                    cacheMgr = CompositeCacheManager.getUnconfiguredInstance();
                    cacheMgr.configure(configFilename);
                } else {
                    cacheMgr = CompositeCacheManager.getInstance();
                }
            }

            return cacheMgr;
        }
    }

    /**
     * Get a CacheAccess which accesses the provided region.
     * <p>
     * @param region Region that return CacheAccess will provide access to
     * @return A CacheAccess which provides access to a given region.
     * @throws CacheException
     */
    public static <K, V> CacheAccess<K, V> getInstance(String region) throws CacheException {
        CompositeCache<K, V> cache = getCacheManager().getCache(region);
        return new CacheAccess<K, V>(cache);
    }

    /**
     * Get a CacheAccess which accesses the provided region.
     * <p>
     * @param region Region that return CacheAccess will provide access to
     * @param icca CacheAttributes for region
     * @return A CacheAccess which provides access to a given region.
     * @throws CacheException
     */
    public static <K, V> CacheAccess<K, V> getInstance(String region, ICompositeCacheAttributes icca)
            throws CacheException {
        CompositeCache<K, V> cache = getCacheManager().getCache(region, icca);
        return new CacheAccess<K, V>(cache);
    }

    /**
     * Get a CacheAccess which accesses the provided region.
     * <p>
     * @param region Region that return CacheAccess will provide access to
     * @param icca CacheAttributes for region
     * @param eattr ElementAttributes for the region
     * @return A CacheAccess which provides access to a given region.
     * @throws CacheException
     */
    public static <K, V> CacheAccess<K, V> getInstance(String region, ICompositeCacheAttributes icca,
            IElementAttributes eattr) throws CacheException {
        CompositeCache<K, V> cache = getCacheManager().getCache(region, icca, eattr);
        return new CacheAccess<K, V>(cache);
    }

    /**
     * Get a GroupCacheAccess which accesses the provided region.
     * <p>
     * @param region Region that return GroupCacheAccess will provide access to
     * @return A GroupCacheAccess which provides access to a given region.
     * @throws CacheException
     */
    public static <K, V> GroupCacheAccess<K, V> getGroupCacheInstance(String region) throws CacheException {
        CompositeCache<GroupAttrName<K>, V> cache = getCacheManager().getCache(region);
        return new GroupCacheAccess<K, V>(cache);
    }

    /**
     * Get a GroupCacheAccess which accesses the provided region.
     * <p>
     * @param region Region that return GroupCacheAccess will provide access to
     * @param icca CacheAttributes for region
     * @return A GroupCacheAccess which provides access to a given region.
     * @throws CacheException
     */
    public static <K, V> GroupCacheAccess<K, V> getGroupCacheInstance(String region, ICompositeCacheAttributes icca)
            throws CacheException {
        CompositeCache<GroupAttrName<K>, V> cache = getCacheManager().getCache(region, icca);
        return new GroupCacheAccess<K, V>(cache);
    }

    /**
     * Get a GroupCacheAccess which accesses the provided region.
     * <p>
     * @param region Region that return CacheAccess will provide access to
     * @param icca CacheAttributes for region
     * @param eattr ElementAttributes for the region
     * @return A GroupCacheAccess which provides access to a given region.
     * @throws CacheException
     */
    public static <K, V> GroupCacheAccess<K, V> getGroupCacheInstance(String region, ICompositeCacheAttributes icca,
            IElementAttributes eattr) throws CacheException {
        CompositeCache<GroupAttrName<K>, V> cache = getCacheManager().getCache(region, icca, eattr);
        return new GroupCacheAccess<K, V>(cache);
    }
}