Coverage report

  %line %branch
org.apache.turbine.util.BufferCache
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 1  
 package org.apache.turbine.util;
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 3  
 /*
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  * Copyright 2001-2005 The Apache Software Foundation.
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  *
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  * Licensed under the Apache License, Version 2.0 (the "License")
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  * you may not use this file except in compliance with the License.
 8  
  * You may obtain a copy of the License at
 9  
  *
 10  
  *     http://www.apache.org/licenses/LICENSE-2.0
 11  
  *
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  * Unless required by applicable law or agreed to in writing, software
 13  
  * distributed under the License is distributed on an "AS IS" BASIS,
 14  
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 15  
  * See the License for the specific language governing permissions and
 16  
  * limitations under the License.
 17  
  */
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 19  
 import org.apache.commons.collections.SequencedHashMap;
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 21  
 /**
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  * A fixed length object cache implementing the LRU algorithm.  Convenient for
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  * buffering recently used objects.
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  *
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  * @author <a href="mailto:dlr@collab.net">Daniel Rall</a>
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  * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
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  * @version $Id: BufferCache.java 278822 2005-09-05 19:53:05Z henning $
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  */
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 public class BufferCache
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     extends SequencedHashMap
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 {
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     /** Serial Version UID */
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     private static final long serialVersionUID = 5206274963401520445L;
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 35  
     /**
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      * The default maximum cache size.
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      */
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     private static final int DEFAULT_MAX_SIZE = 35;
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 40  
     /**
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      * The size of the cache.  The newest elements in the sequence are kept
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      * toward the end.
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      */
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     private int maxSize;
 45  
 
 46  
     /**
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      * Creates a new instance with default storage buffer pre-allocated.
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      */
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     public BufferCache()
 50  
     {
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         this(DEFAULT_MAX_SIZE);
 52  0
     }
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 54  
     /**
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      * Creates a new instance with the specified storage buffer pre-allocated.
 56  
      *
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      * @param maxSize The maximum size of the cache.
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      */
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     public BufferCache(int maxSize)
 60  
     {
 61  0
         super(maxSize);
 62  0
         this.maxSize = maxSize;
 63  0
     }
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 65  
     /**
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      * Stores the provided key/value pair, freshening its list index if the
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      * specified key already exists.
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      *
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      * @param key   The key to the provided value.
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      * @param value The value to store.
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      * @return      The previous value for the specified key, or
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      *              <code>null</code> if none.
 73  
      */
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     public synchronized Object put(Object key, Object value)
 75  
     {
 76  0
         int size = size();
 77  0
         if (size > 0 && size + 1 >= maxSize)
 78  
         {
 79  
             // Stay within constraints of allocated buffer by releasing the
 80  
             // eldest buffered object.
 81  0
             remove(0);
 82  
         }
 83  0
         return super.put(key, value);
 84  
     }
 85  
 
 86  
     /**
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      * Retrieves the value associated with the provided key, freshening the
 88  
      * sequence of the key as well.
 89  
      *
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      * @param key The key whose value to retrieve.
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      * @return    The keyed value.
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      */
 93  
     public synchronized Object get(Object key)
 94  
     {
 95  0
         return super.get(key);
 96  
     }
 97  
 }

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