/*

  * Copyright 2001-2004 The Apache Software Foundation

  *

  * Licensed 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.

  */

 package org.apache.commons.cache;

 import java.io.Serializable;

 /**

  * A {@link Cache} that doesn't.

  * @version $Id: NoOpCache.java 155435 2005-02-26 13:17:27Z dirkv $

  * @author Rodney Waldhoff

  */

 public class NoOpCache extends BaseCache implements Cache {

   /** Returns <tt>false</tt>. */

   public boolean store(Serializable key, Serializable val, Long expiry, Long cost, Serializable group) {

     broadcastStoreRequested(key,val,expiry,cost,group);

     broadcastNotStored(key,val,expiry,cost,group);

     return false;

   }

   /** Returns <tt>null</tt>. */

   public Serializable retrieve(Serializable key) {

     broadcastRetrieveRequested(key);

     broadcastNotRetrieved(key);

     return null;

   }

   /** Returns an empty array. */

   public Serializable[] getKeysForGroup(Serializable group) {

     return new Serializable[0];

   }

   /** Returns <tt>false</tt> */

   public boolean contains(Serializable key) {

     return false;

   }

   /** No-op. */

   public void clear(Serializable key) {

   }

   /** No-op. */

   public void clearGroup(Serializable group) {

   }

   /** No-op. */

   public void clear() {

   }

   /** Throws {@link UnsupportedOperationException} */

   public long getStat(CacheStat stat) throws UnsupportedOperationException {

     throw new UnsupportedOperationException();

   }

 }