001    /*
002     * Licensed to the Apache Software Foundation (ASF) under one
003     * or more contributor license agreements.  See the NOTICE file
004     * distributed with this work for additional information
005     * regarding copyright ownership.  The ASF licenses this file
006     * to you under the Apache License, Version 2.0 (the
007     * "License"); you may not use this file except in compliance
008     * with the License.  You may obtain a copy of the License at
009     *
010     *     http://www.apache.org/licenses/LICENSE-2.0
011     *
012     * Unless required by applicable law or agreed to in writing,
013     * software distributed under the License is distributed on an
014     * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015     * KIND, either express or implied.  See the License for the
016     * specific language governing permissions and limitations
017     * under the License.
018     */
019    package org.apache.shiro.cache;
020    
021    import org.apache.shiro.util.SoftHashMap;
022    
023    /**
024     * Simple memory-only based {@link CacheManager CacheManager} implementation usable in production
025     * environments.  It will not cause memory leaks as it produces {@link Cache Cache}s backed by
026     * {@link SoftHashMap SoftHashMap}s which auto-size themselves based on the runtime environment's memory
027     * limitations and garbage collection behavior.
028     * <p/>
029     * While the {@code Cache} instances created are thread-safe, they do not offer any enterprise-level features such as
030     * cache coherency, optimistic locking, failover or other similar features.  For more enterprise features, consider
031     * using a different {@code CacheManager} implementation backed by an enterprise-grade caching product (EhCache,
032     * TerraCotta, Coherence, GigaSpaces, etc, etc).
033     *
034     * @since 1.0
035     */
036    public class MemoryConstrainedCacheManager extends AbstractCacheManager {
037    
038        /**
039         * Returns a new {@link MapCache MapCache} instance backed by a {@link SoftHashMap}.
040         *
041         * @param name the name of the cache
042         * @return a new {@link MapCache MapCache} instance backed by a {@link SoftHashMap}.
043         */
044        @Override
045        protected Cache createCache(String name) {
046            return new MapCache<Object, Object>(name, new SoftHashMap<Object, Object>());
047        }
048    }