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1   /**
2    * Copyright 2010 The Apache Software Foundation
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, software
15   * distributed under the License is distributed on an "AS IS" BASIS,
16   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
17   * See the License for the specific language governing permissions and
18   * limitations under the License.
19   */
20  package org.apache.hadoop.hbase.util;
21  
22  import java.lang.ref.ReferenceQueue;
23  import java.lang.ref.SoftReference;
24  import java.util.Map;
25  
26  /**
27   * A SoftReference derivative so that we can track down what keys to remove.
28   */
29  class SoftValue<K, V> extends SoftReference<V> implements Map.Entry<K, V> {
30    private final K key;
31  
32    @SuppressWarnings("unchecked")
33    SoftValue(K key, V value, ReferenceQueue queue) {
34      super(value, queue);
35      this.key = key;
36    }
37  
38    public K getKey() {
39      return this.key;
40    }
41  
42    public V getValue() {
43      return get();
44    }
45  
46    public V setValue(V value) {
47      throw new RuntimeException("Not implemented");
48    }
49  }