001 package org.apache.turbine.om;
002
003
004 /*
005 * Licensed to the Apache Software Foundation (ASF) under one
006 * or more contributor license agreements. See the NOTICE file
007 * distributed with this work for additional information
008 * regarding copyright ownership. The ASF licenses this file
009 * to you under the Apache License, Version 2.0 (the
010 * "License"); you may not use this file except in compliance
011 * with the License. You may obtain a copy of the License at
012 *
013 * http://www.apache.org/licenses/LICENSE-2.0
014 *
015 * Unless required by applicable law or agreed to in writing,
016 * software distributed under the License is distributed on an
017 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
018 * KIND, either express or implied. See the License for the
019 * specific language governing permissions and limitations
020 * under the License.
021 */
022
023
024 import java.util.HashMap;
025 import java.util.Map;
026
027 import org.apache.fulcrum.pool.Recyclable;
028 import org.apache.turbine.services.pull.ApplicationTool;
029
030 /**
031 * A Pull tool to make om objects available to a template
032 *
033 * @author <a href="mailto:jmcnally@collab.net">John D. McNally</a>
034 * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
035 * @version $Id: OMTool.java 1078552 2011-03-06 19:58:46Z tv $
036 */
037 public class OMTool implements ApplicationTool, Recyclable
038 {
039 // private RunData data;
040 protected HashMap<String, Object> omMap;
041
042 // note the following could be a static attribute to reduce memory
043 // footprint. Might require a service to front load the
044 // PullHelpers to avoid MT issues. A multiple write is not so bad
045 // though
046
047 /** The cache of PullHelpers. **/
048 private static Map<String, OMTool.PullHelper> pullMap = new HashMap<String, OMTool.PullHelper>();
049
050 /**
051 * The Factory responsible for retrieving the
052 * objects from storage
053 */
054 protected RetrieverFactory omFactory;
055
056 public OMTool()throws Exception
057 {
058 omMap = new HashMap<String, Object>();
059 //String className = Turbine.getConfiguration()
060 // .getString("tool.om.factory");
061 // RetrieverFactory omFactory =
062 // (RetrieverFactory)Class.forName(className).newInstance();
063 }
064
065 /**
066 * Prepares tool for a single request
067 */
068 public void init(Object runData)
069 {
070 // data = (RunData)runData;
071 }
072
073 /**
074 * Implementation of ApplicationTool interface is not needed for this
075 * method as the tool is request scoped
076 */
077 public void refresh()
078 {
079 // empty
080 }
081
082 /**
083 * Inner class to present a nice interface to the template designer
084 */
085 protected class PullHelper
086 {
087 String omName;
088
089 protected PullHelper(String omName)
090 {
091 this.omName = omName;
092 }
093
094 public Object setKey(String key)
095 throws Exception
096 {
097 Object om = null;
098
099 String inputKey = omName + key;
100 if (omMap.containsKey(inputKey))
101 {
102 om = omMap.get(inputKey);
103 }
104 else
105 {
106 om = omFactory.getInstance(omName).retrieve(key);
107 omMap.put(inputKey, om);
108 }
109
110 return om;
111 }
112 }
113
114 public Object get(String omName) throws Exception
115 {
116 if (!pullMap.containsKey(omName))
117 {
118 // MT could overwrite a PullHelper, but that is not a problem
119 // should still synchronize to avoid two threads adding at
120 // same time
121 synchronized (this.getClass())
122 {
123 pullMap.put(omName, new OMTool.PullHelper(omName));
124 }
125 }
126
127 return pullMap.get(omName);
128 }
129
130 public Object get(String omName, String key) throws Exception
131 {
132 return ((OMTool.PullHelper) get(omName)).setKey(key);
133 }
134
135
136 public String getName()
137 {
138 return "om";
139 }
140
141
142 // ****************** Recyclable implementation ************************
143
144 private boolean disposed;
145
146 /**
147 * Recycles the object for a new client. Recycle methods with
148 * parameters must be added to implementing object and they will be
149 * automatically called by pool implementations when the object is
150 * taken from the pool for a new client. The parameters must
151 * correspond to the parameters of the constructors of the object.
152 * For new objects, constructors can call their corresponding recycle
153 * methods whenever applicable.
154 * The recycle methods must call their super.
155 */
156 public void recycle()
157 {
158 disposed = false;
159 }
160
161 /**
162 * Disposes the object after use. The method is called
163 * when the object is returned to its pool.
164 * The dispose method must call its super.
165 */
166 public void dispose()
167 {
168 omMap.clear();
169 // data = null;
170 disposed = true;
171 }
172
173 /**
174 * Checks whether the recyclable has been disposed.
175 * @return true, if the recyclable is disposed.
176 */
177 public boolean isDisposed()
178 {
179 return disposed;
180 }
181 }
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