1 package org.apache.commons.jcs.engine.memory.mru;
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.io.IOException;
23
24 import org.apache.commons.jcs.engine.behavior.ICacheElement;
25 import org.apache.commons.jcs.engine.memory.AbstractDoubleLinkedListMemoryCache;
26 import org.apache.commons.jcs.engine.memory.util.MemoryElementDescriptor;
27
28 /**
29 * The most recently used items move to the front of the list and get spooled to disk if the cache
30 * hub is configured to use a disk cache.
31 */
32 public class MRUMemoryCache<K, V>
33 extends AbstractDoubleLinkedListMemoryCache<K, V>
34 {
35 /**
36 * Adds the item to the front of the list. A put doesn't count as a usage.
37 * <p>
38 * It's not clear if the put operation should be different. Perhaps this should remove the oldest
39 * if full, and then put.
40 * <p>
41 * @param ce
42 * @return MemoryElementDescriptor the new node
43 * @throws IOException
44 */
45 @Override
46 protected MemoryElementDescriptor<K, V> adjustListForUpdate( ICacheElement<K, V> ce )
47 throws IOException
48 {
49 return addFirst( ce );
50 }
51
52 /**
53 * Makes the item the last in the list.
54 * <p>
55 * @param me
56 */
57 @Override
58 protected void adjustListForGet( MemoryElementDescriptor<K, V> me )
59 {
60 list.makeLast( me );
61 }
62 }