1 package org.apache.turbine.om;
2
3 /* ====================================================================
4 * The Apache Software License, Version 1.1
5 *
6 * Copyright (c) 2001 The Apache Software Foundation. All rights
7 * reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 *
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 *
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in
18 * the documentation and/or other materials provided with the
19 * distribution.
20 *
21 * 3. The end-user documentation included with the redistribution,
22 * if any, must include the following acknowledgment:
23 * "This product includes software developed by the
24 * Apache Software Foundation (http://www.apache.org/)."
25 * Alternately, this acknowledgment may appear in the software itself,
26 * if and wherever such third-party acknowledgments normally appear.
27 *
28 * 4. The names "Apache" and "Apache Software Foundation" and
29 * "Apache Turbine" must not be used to endorse or promote products
30 * derived from this software without prior written permission. For
31 * written permission, please contact apache@apache.org.
32 *
33 * 5. Products derived from this software may not be called "Apache",
34 * "Apache Turbine", nor may "Apache" appear in their name, without
35 * prior written permission of the Apache Software Foundation.
36 *
37 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
38 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
39 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
40 * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
41 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
42 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
43 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
44 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
45 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
46 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
47 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
48 * SUCH DAMAGE.
49 * ====================================================================
50 *
51 * This software consists of voluntary contributions made by many
52 * individuals on behalf of the Apache Software Foundation. For more
53 * information on the Apache Software Foundation, please see
54 * <http://www.apache.org/>;.
55 */
56
57 import java.util.HashMap;
58 import java.util.Map;
59 import org.apache.turbine.util.RunData;
60 import org.apache.turbine.util.StringUtils;
61 import org.apache.turbine.util.ParameterParser;
62 import org.apache.turbine.util.Log;
63 import org.apache.turbine.util.TurbineException;
64 import org.apache.turbine.services.resources.TurbineResources;
65 import org.apache.turbine.services.pull.ApplicationTool;
66 import org.apache.turbine.util.pool.Recyclable;
67
68 /***
69 * A Pull tool to make om objects available to a template
70 *
71 * @author <a href="mailto:jmcnally@collab.net">John D. McNally</a>
72 * @version $Id$
73 */
74 public class OMTool
75 implements ApplicationTool, Recyclable
76 {
77 // private RunData data;
78 private HashMap omMap;
79
80 // note the following could be a static attribute to reduce memory
81 // footprint. Might require a service to front load the
82 // PullHelpers to avoid MT issues. A multiple write is not so bad
83 // though
84
85 /*** The cache of PullHelpers. **/
86 private static Map pullMap = new HashMap();
87
88 /***
89 * The Factory responsible for retrieving the
90 * objects from storage
91 */
92 private RetrieverFactory omFactory;
93
94 public OMTool()
95 throws Exception
96 {
97 omMap = new HashMap();
98 String className = TurbineResources.getString("tool.om.factory");
99 // RetrieverFactory omFactory =
100 // (RetrieverFactory)Class.forName(className).newInstance();
101 }
102
103 /***
104 * Prepares tool for a single request
105 */
106 public void init(Object runData)
107 {
108 // data = (RunData)runData;
109 }
110
111 /***
112 * Implementation of ApplicationTool interface is not needed for this
113 * method as the tool is request scoped
114 */
115 public void refresh()
116 {
117 // empty
118 }
119
120 /***
121 * Inner class to present a nice interface to the template designer
122 */
123 private class PullHelper
124 {
125 String omName;
126
127 private PullHelper(String omName)
128 {
129 this.omName = omName;
130 }
131
132 public Object setKey(String key)
133 throws Exception
134 {
135 Object om = null;
136
137 String inputKey = omName + key;
138 if ( omMap.containsKey(inputKey) )
139 {
140 om = omMap.get(inputKey);
141 }
142 else
143 {
144 om = omFactory.getInstance(omName).retrieve(key);
145 omMap.put(inputKey, om);
146 }
147
148 return om;
149 }
150 }
151
152 public Object get(String omName)
153 throws Exception
154 {
155 if ( !pullMap.containsKey(omName) )
156 {
157 // MT could overwrite a PullHelper, but that is not a problem
158 // should still synchronize to avoid two threads adding at
159 // same time
160 synchronized (this.getClass())
161 {
162 pullMap.put(omName, new OMTool.PullHelper(omName));
163 }
164 }
165
166 return pullMap.get(omName);
167 }
168
169 public Object get(String omName, String key)
170 throws Exception
171 {
172 return ((OMTool.PullHelper)get(omName)).setKey(key);
173 }
174
175
176 public String getName()
177 {
178 return "om";
179 }
180
181
182 // ****************** Recyclable implementation ************************
183
184 private boolean disposed;
185
186 /***
187 * Recycles the object for a new client. Recycle methods with
188 * parameters must be added to implementing object and they will be
189 * automatically called by pool implementations when the object is
190 * taken from the pool for a new client. The parameters must
191 * correspond to the parameters of the constructors of the object.
192 * For new objects, constructors can call their corresponding recycle
193 * methods whenever applicable.
194 * The recycle methods must call their super.
195 */
196 public void recycle()
197 {
198 disposed = false;
199 }
200
201 /***
202 * Disposes the object after use. The method is called
203 * when the object is returned to its pool.
204 * The dispose method must call its super.
205 */
206 public void dispose()
207 {
208 omMap.clear();
209 // data = null;
210
211 disposed = true;
212 }
213
214 /***
215 * Checks whether the recyclable has been disposed.
216 * @return true, if the recyclable is disposed.
217 */
218 public boolean isDisposed()
219 {
220 return disposed;
221 }
222
223 }
224
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