1 /*
2 * This file is part of Waarp Project (named also Waarp or GG).
3 *
4 * Copyright (c) 2019, Waarp SAS, and individual contributors by the @author
5 * tags. See the COPYRIGHT.txt in the distribution for a full listing of
6 * individual contributors.
7 *
8 * All Waarp Project is free software: you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation, either version 3 of the License, or (at your
11 * option) any later version.
12 *
13 * Waarp is distributed in the hope that it will be useful, but WITHOUT ANY
14 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
15 * A PARTICULAR PURPOSE. See the GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License along with
18 * Waarp . If not, see <http://www.gnu.org/licenses/>.
19 */
20 package org.waarp.common.lru;
21
22 import java.util.Collections;
23 import java.util.LinkedHashMap;
24 import java.util.Map;
25 import java.util.Map.Entry;
26
27 /**
28 * Simple LRU Cache
29 */
30 public class SimpleLRUCache<K, V> extends LinkedHashMap<K, V> {
31 private static final long serialVersionUID = -3505777964745783339L;
32 private final int capacity; // Maximum number of items in the cache.
33
34 public static <K, V> Map<K, V> create(final int capacity) {
35 return Collections.synchronizedMap(new SimpleLRUCache<K, V>(capacity));
36 }
37
38 public SimpleLRUCache(final int capacity) {
39 super(capacity + 1, 1.0f, true); // Pass 'true' for accessOrder.
40 this.capacity = capacity;
41 }
42
43 @Override
44 protected final boolean removeEldestEntry(final Entry<K, V> entry) {
45 return size() > capacity;
46 }
47 }