1 package org.apache.turbine.om;
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.concurrent.ConcurrentHashMap;
23 import java.util.concurrent.ConcurrentMap;
24
25 import org.apache.fulcrum.pool.Recyclable;
26 import org.apache.turbine.Turbine;
27 import org.apache.turbine.services.pull.ApplicationTool;
28
29 /**
30 * A Pull tool to make om objects available to a template
31 *
32 * @author <a href="mailto:jmcnally@collab.net">John D. McNally</a>
33 * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
34 * @version $Id: OMTool.java 1706425 2015-10-02 14:47:51Z tv $
35 */
36 public class OMTool implements ApplicationTool, Recyclable
37 {
38 protected ConcurrentHashMap<String, Object> omMap;
39
40 // note the following could be a static attribute to reduce memory
41 // footprint. Might require a service to front load the
42 // PullHelpers to avoid MT issues. A multiple write is not so bad
43 // though
44
45 /** The cache of PullHelpers. **/
46 private ConcurrentMap<String, OMTool.PullHelper> pullMap =
47 new ConcurrentHashMap<String, OMTool.PullHelper>();
48
49 /**
50 * The Factory responsible for retrieving the
51 * objects from storage
52 */
53 protected RetrieverFactory omFactory;
54
55 /**
56 * Default constructor
57 * @throws Exception if creating the factory fails
58 */
59 public OMTool() throws Exception
60 {
61 omMap = new ConcurrentHashMap<String, Object>();
62 String className = Turbine.getConfiguration().getString("tool.om.factory");
63 this.omFactory = (RetrieverFactory)Class.forName(className).newInstance();
64 }
65
66 /**
67 * Prepares tool for a single request
68 *
69 * @param data the initialization data
70 */
71 @Override
72 public void init(Object data)
73 {
74 // data = (RunData)data;
75 }
76
77 /**
78 * Implementation of ApplicationTool interface is not needed for this
79 * method as the tool is request scoped
80 */
81 @Override
82 public void refresh()
83 {
84 // empty
85 }
86
87 /**
88 * Inner class to present a nice interface to the template designer
89 */
90 protected class PullHelper
91 {
92 String omName;
93
94 protected PullHelper(String omName)
95 {
96 this.omName = omName;
97 }
98
99 public Object setKey(String key)
100 throws Exception
101 {
102 Object om = null;
103 String inputKey = omName + key;
104
105 if (omMap.containsKey(inputKey))
106 {
107 om = omMap.get(inputKey);
108 }
109 else
110 {
111 om = omFactory.getInstance(omName).retrieve(key);
112 omMap.put(inputKey, om);
113 }
114
115 return om;
116 }
117 }
118
119 /**
120 * Get the {@link PullHelper} object with the given name
121 * @param omName the object name
122 * @return the PullHelper
123 * @throws Exception if retrieving the object fails
124 */
125 public PullHelper get(String omName) throws Exception
126 {
127 PullHelper ph = pullMap.putIfAbsent(omName, new OMTool.PullHelper(omName));
128 if (ph == null)
129 {
130 return pullMap.get(omName);
131 }
132
133 return ph;
134 }
135
136 /**
137 * Get the object with the given name and key
138 * @param omName the object name
139 * @param key the object key
140 * @return the object
141 * @throws Exception if retrieving the object fails
142 */
143 public Object get(String omName, String key) throws Exception
144 {
145 return get(omName).setKey(key);
146 }
147
148 // ****************** Recyclable implementation ************************
149
150 private boolean disposed;
151
152 /**
153 * Recycles the object for a new client. Recycle methods with
154 * parameters must be added to implementing object and they will be
155 * automatically called by pool implementations when the object is
156 * taken from the pool for a new client. The parameters must
157 * correspond to the parameters of the constructors of the object.
158 * For new objects, constructors can call their corresponding recycle
159 * methods whenever applicable.
160 * The recycle methods must call their super.
161 */
162 @Override
163 public void recycle()
164 {
165 disposed = false;
166 }
167
168 /**
169 * Disposes the object after use. The method is called
170 * when the object is returned to its pool.
171 * The dispose method must call its super.
172 */
173 @Override
174 public void dispose()
175 {
176 omMap.clear();
177 disposed = true;
178 }
179
180 /**
181 * Checks whether the recyclable has been disposed.
182 * @return true, if the recyclable is disposed.
183 */
184 @Override
185 public boolean isDisposed()
186 {
187 return disposed;
188 }
189 }