1 /***
2 * Copyright 2003-2010 Terracotta, Inc.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 package net.sf.ehcache.store;
18
19 import net.sf.ehcache.Element;
20
21
22 /***
23 * Contains common LFU policy code for use between the LfuMemoryStore and the DiskStore, which also
24 * uses an LfuPolicy for evictions.
25 *
26 * @author Greg Luck
27 * @version $Id: LfuPolicy.html 13146 2011-08-01 17:12:39Z oletizi $
28 */
29 public class LfuPolicy extends AbstractPolicy {
30
31 /***
32 * The name of this policy as a string literal
33 */
34 public static final String NAME = "LFU";
35
36 /***
37 * @return the name of the Policy. Inbuilt examples are LRU, LFU and FIFO.
38 */
39 public String getName() {
40 return NAME;
41 }
42
43 /***
44 * Compares the desirableness for eviction of two elements
45 *
46 * Compares hit counts. If both zero,
47 *
48 * @param element1 the element to compare against
49 * @param element2 the element to compare
50 * @return true if the second element is preferable to the first element for ths policy
51 */
52 public boolean compare(Element element1, Element element2) {
53 return element2.getHitCount() < element1.getHitCount();
54
55 }
56
57 }