1 package org.apache.velocity.runtime.resource;
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.Collections;
23 import java.util.HashMap;
24 import java.util.Hashtable;
25 import java.util.Map;
26 import java.util.Iterator;
27
28 import org.apache.commons.collections.map.LRUMap;
29 import org.apache.velocity.runtime.RuntimeConstants;
30 import org.apache.velocity.runtime.RuntimeServices;
31 import org.apache.velocity.util.MapFactory;
32
33 /**
34 * Default implementation of the resource cache for the default
35 * ResourceManager. The cache uses a <i>least recently used</i> (LRU)
36 * algorithm, with a maximum size specified via the
37 * <code>resource.manager.cache.size</code> property (idenfied by the
38 * {@link
39 * org.apache.velocity.runtime.RuntimeConstants#RESOURCE_MANAGER_DEFAULTCACHE_SIZE}
40 * constant). This property get be set to <code>0</code> or less for
41 * a greedy, unbounded cache (the behavior from pre-v1.5).
42 *
43 * @author <a href="mailto:geirm@apache.org">Geir Magnusson Jr.</a>
44 * @author <a href="mailto:dlr@finemaltcoding.com">Daniel Rall</a>
45 * @version $Id: ResourceCacheImpl.java 685385 2008-08-12 23:59:06Z nbubna $
46 */
47 public class ResourceCacheImpl implements ResourceCache
48 {
49 /**
50 * Cache storage, assumed to be thread-safe.
51 */
52 protected Map cache = MapFactory.create(512, 0.5f, 30, false);
53
54 /**
55 * Runtime services, generally initialized by the
56 * <code>initialize()</code> method.
57 */
58 protected RuntimeServices rsvc = null;
59
60 /**
61 * @see org.apache.velocity.runtime.resource.ResourceCache#initialize(org.apache.velocity.runtime.RuntimeServices)
62 */
63 public void initialize( RuntimeServices rs )
64 {
65 rsvc = rs;
66
67 int maxSize =
68 rsvc.getInt(RuntimeConstants.RESOURCE_MANAGER_DEFAULTCACHE_SIZE, 89);
69 if (maxSize > 0)
70 {
71 // Create a whole new Map here to avoid hanging on to a
72 // handle to the unsynch'd LRUMap for our lifetime.
73 Map lruCache = Collections.synchronizedMap(new LRUMap(maxSize));
74 lruCache.putAll(cache);
75 cache = lruCache;
76 }
77 rsvc.getLog().debug("ResourceCache: initialized ("+this.getClass()+") with "+
78 cache.getClass()+" cache map.");
79 }
80
81 /**
82 * @see org.apache.velocity.runtime.resource.ResourceCache#get(java.lang.Object)
83 */
84 public Resource get( Object key )
85 {
86 return (Resource) cache.get( key );
87 }
88
89 /**
90 * @see org.apache.velocity.runtime.resource.ResourceCache#put(java.lang.Object, org.apache.velocity.runtime.resource.Resource)
91 */
92 public Resource put( Object key, Resource value )
93 {
94 return (Resource) cache.put( key, value );
95 }
96
97 /**
98 * @see org.apache.velocity.runtime.resource.ResourceCache#remove(java.lang.Object)
99 */
100 public Resource remove( Object key )
101 {
102 return (Resource) cache.remove( key );
103 }
104
105 /**
106 * @see org.apache.velocity.runtime.resource.ResourceCache#enumerateKeys()
107 */
108 public Iterator enumerateKeys()
109 {
110 return cache.keySet().iterator();
111 }
112 }
113