001 /* 002 * Copyright 2001-2004 The Apache Software Foundation 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * http://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 */ 016 package org.apache.commons.cache; 017 018 import java.io.Serializable; 019 020 /** 021 * A {@link Cache} that doesn't. 022 * @version $Id: NoOpCache.java 155435 2005-02-26 13:17:27Z dirkv $ 023 * @author Rodney Waldhoff 024 */ 025 public class NoOpCache extends BaseCache implements Cache { 026 /** Returns <tt>false</tt>. */ 027 public boolean store(Serializable key, Serializable val, Long expiry, Long cost, Serializable group) { 028 broadcastStoreRequested(key,val,expiry,cost,group); 029 broadcastNotStored(key,val,expiry,cost,group); 030 return false; 031 } 032 033 /** Returns <tt>null</tt>. */ 034 public Serializable retrieve(Serializable key) { 035 broadcastRetrieveRequested(key); 036 broadcastNotRetrieved(key); 037 return null; 038 } 039 040 /** Returns an empty array. */ 041 public Serializable[] getKeysForGroup(Serializable group) { 042 return new Serializable[0]; 043 } 044 045 /** Returns <tt>false</tt> */ 046 public boolean contains(Serializable key) { 047 return false; 048 } 049 050 /** No-op. */ 051 public void clear(Serializable key) { 052 } 053 054 /** No-op. */ 055 public void clearGroup(Serializable group) { 056 } 057 058 /** No-op. */ 059 public void clear() { 060 } 061 062 /** Throws {@link UnsupportedOperationException} */ 063 public long getStat(CacheStat stat) throws UnsupportedOperationException { 064 throw new UnsupportedOperationException(); 065 } 066 }