001    /*--------------------------------------------------------------------------+
002    $Id: LRUCachingParameterizedFactory.java 27446 2010-04-11 09:57:00Z heineman $
003    |                                                                          |
004    | Copyright 2005-2010 Technische Universitaet Muenchen                     |
005    |                                                                          |
006    | Licensed under the Apache License, Version 2.0 (the "License");          |
007    | you may not use this file except in compliance with the License.         |
008    | 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, software      |
013    | distributed under the License is distributed on an "AS IS" BASIS,        |
014    | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
015    | See the License for the specific language governing permissions and      |
016    | limitations under the License.                                           |
017    +--------------------------------------------------------------------------*/
018    package edu.tum.cs.commons.factory;
019    
020    import edu.tum.cs.commons.assertion.CCSMPre;
021    import edu.tum.cs.commons.cache.LRUCacheBase;
022    import edu.tum.cs.commons.cache.LRUStraightCacheBase;
023    import edu.tum.cs.commons.error.NeverThrownRuntimeException;
024    
025    /**
026     * Caching factory which can reuse created objects. Creation is delegated to an
027     * inner factory, while for caching a {@link LRUCacheBase} is used.
028     * 
029     * @param <T>
030     *            Type that gets created by the factory.
031     * @param <P>
032     *            Parameter that is used for creation.
033     * @param <X>
034     *            Exception that can get thrown during execution of the factory
035     *            method. If no exception is thrown, use
036     *            {@link NeverThrownRuntimeException}.
037     * 
038     * @author hummelb
039     * @author $Author: heineman $
040     * @version $Rev: 27446 $
041     * @levd.rating GREEN Hash: 5D97F2DF67786BC74BEB3611B6017360
042     */
043    public class LRUCachingParameterizedFactory<T, P, X extends Exception>
044                    extends LRUStraightCacheBase<P, T, X> implements
045                    IParameterizedFactory<T, P, X> {
046    
047            /** The wrapped factory we delegate to. */
048            private final IParameterizedFactory<T, P, X> inner;
049    
050            /** Constructor. */
051            public LRUCachingParameterizedFactory(
052                            IParameterizedFactory<T, P, X> inner, int maxSize) {
053                    super(maxSize);
054                    CCSMPre.isNotNull(inner, "Delegate factory may not be null!");
055                    this.inner = inner;
056            }
057    
058            /**
059             * {@inheritDoc}
060             * <p>
061             * Delegates to the inner factory.
062             */
063            @Override
064            protected T obtainItem(P identifier) throws X {
065                    return inner.create(identifier);
066            }
067    
068            /**
069             * {@inheritDoc}
070             * <p>
071             * Forwards to the {@link #getItem(Object)} method.
072             */
073            @Override
074            public T create(P parameter) throws X {
075                    return getItem(parameter);
076            }
077    
078    }