001package org.apache.turbine.om; 002 003/* 004 * Licensed to the Apache Software Foundation (ASF) under one 005 * or more contributor license agreements. See the NOTICE file 006 * distributed with this work for additional information 007 * regarding copyright ownership. The ASF licenses this file 008 * to you under the Apache License, Version 2.0 (the 009 * "License"); you may not use this file except in compliance 010 * with the License. You may obtain a copy of the License at 011 * 012 * http://www.apache.org/licenses/LICENSE-2.0 013 * 014 * Unless required by applicable law or agreed to in writing, 015 * software distributed under the License is distributed on an 016 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 017 * KIND, either express or implied. See the License for the 018 * specific language governing permissions and limitations 019 * under the License. 020 */ 021 022import java.util.concurrent.ConcurrentHashMap; 023import java.util.concurrent.ConcurrentMap; 024 025import org.apache.fulcrum.pool.Recyclable; 026import org.apache.turbine.Turbine; 027import org.apache.turbine.services.pull.ApplicationTool; 028 029/** 030 * A Pull tool to make om objects available to a template 031 * 032 * @author <a href="mailto:jmcnally@collab.net">John D. McNally</a> 033 * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a> 034 * @version $Id: OMTool.java 1706425 2015-10-02 14:47:51Z tv $ 035 */ 036public class OMTool implements ApplicationTool, Recyclable 037{ 038 protected ConcurrentHashMap<String, Object> omMap; 039 040 // note the following could be a static attribute to reduce memory 041 // footprint. Might require a service to front load the 042 // PullHelpers to avoid MT issues. A multiple write is not so bad 043 // though 044 045 /** The cache of PullHelpers. **/ 046 private ConcurrentMap<String, OMTool.PullHelper> pullMap = 047 new ConcurrentHashMap<String, OMTool.PullHelper>(); 048 049 /** 050 * The Factory responsible for retrieving the 051 * objects from storage 052 */ 053 protected RetrieverFactory omFactory; 054 055 /** 056 * Default constructor 057 * @throws Exception if creating the factory fails 058 */ 059 public OMTool() throws Exception 060 { 061 omMap = new ConcurrentHashMap<String, Object>(); 062 String className = Turbine.getConfiguration().getString("tool.om.factory"); 063 this.omFactory = (RetrieverFactory)Class.forName(className).newInstance(); 064 } 065 066 /** 067 * Prepares tool for a single request 068 * 069 * @param data the initialization data 070 */ 071 @Override 072 public void init(Object data) 073 { 074 // data = (RunData)data; 075 } 076 077 /** 078 * Implementation of ApplicationTool interface is not needed for this 079 * method as the tool is request scoped 080 */ 081 @Override 082 public void refresh() 083 { 084 // empty 085 } 086 087 /** 088 * Inner class to present a nice interface to the template designer 089 */ 090 protected class PullHelper 091 { 092 String omName; 093 094 protected PullHelper(String omName) 095 { 096 this.omName = omName; 097 } 098 099 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}