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1   package org.apache.commons.jcs.utils.struct;
2   
3   /*
4    * Licensed to the Apache Software Foundation (ASF) under one
5    * or more contributor license agreements.  See the NOTICE file
6    * distributed with this work for additional information
7    * regarding copyright ownership.  The ASF licenses this file
8    * to you under the Apache License, Version 2.0 (the
9    * "License"); you may not use this file except in compliance
10   * with the License.  You may obtain a copy of the License at
11   *
12   *   http://www.apache.org/licenses/LICENSE-2.0
13   *
14   * Unless required by applicable law or agreed to in writing,
15   * software distributed under the License is distributed on an
16   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17   * KIND, either express or implied.  See the License for the
18   * specific language governing permissions and limitations
19   * under the License.
20   */
21  
22  import java.util.concurrent.atomic.AtomicInteger;
23  
24  /**
25   *
26   * @author Wiktor Niesiob─Ödzki
27   *
28   *         Simple LRUMap implementation that keeps the number of the objects below or equal maxObjects
29   *
30   * @param <K>
31   * @param <V>
32   */
33  public class LRUMap<K, V> extends AbstractLRUMap<K, V>
34  {
35  
36      /** if the max is less than 0, there is no limit! */
37      int maxObjects = -1;
38      AtomicInteger counter = new AtomicInteger(0);
39  
40      public LRUMap()
41      {
42          super();
43      }
44  
45      /**
46       *
47       * @param maxObjects
48       *            maximum number to keep in the map
49       */
50      public LRUMap(int maxObjects)
51      {
52          super();
53          this.maxObjects = maxObjects;
54      }
55  
56      @Override
57      public boolean shouldRemove()
58      {
59          return maxObjects > 0 && this.size() > maxObjects;
60      }
61  
62      public Object getMaxCounter()
63      {
64          return maxObjects;
65      }
66  }