001 package org.apache.ojb.broker.transaction.tm;
002
003 /* Copyright 2004-2005 The Apache Software Foundation
004 *
005 * Licensed under the Apache License, Version 2.0 (the "License");
006 * you may not use this file except in compliance with the License.
007 * You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018 import javax.transaction.TransactionManager;
019
020 import org.apache.commons.lang.SystemUtils;
021 import org.apache.ojb.broker.core.NamingLocator;
022 import org.apache.ojb.broker.util.ClassHelper;
023 import org.apache.ojb.broker.util.logging.Logger;
024 import org.apache.ojb.broker.util.logging.LoggerFactory;
025
026 /**
027 * Abstract base class implementation of the {@link TransactionManagerFactory} interface, all
028 * derived classes have to implement method {@link #getLookupInfo()}.
029 *
030 * @author <a href="mailto:armin@codeAuLait.de">Armin Waibel</a>
031 * @version $Id: AbstractTransactionManagerFactory.java,v 1.1 2007-08-24 22:17:41 ewestfal Exp $
032 */
033
034 public abstract class AbstractTransactionManagerFactory implements TransactionManagerFactory
035 {
036 private static Logger log = LoggerFactory.getLogger(AbstractTransactionManagerFactory.class);
037
038 /**
039 * Returns "getTransactionManager";
040 */
041 public static String TM_DEFAULT_METHOD_NAME = "getTransactionManager";
042
043
044 private static TransactionManager tm = null;
045
046 /**
047 * Returns an array of possible JNDI lookup / class names for
048 * the {@link javax.transaction.TransactionManager} instance. An array was used
049 * because for different application server versions the
050 * JNDI/class name may change.
051 * <p/>
052 * Expect an [n][3] string array. Following arguments are available:
053 * <ul>
054 * <li>info[i][0] = short description of used TM, e.g. appServer name</li>
055 * <li>info[i][2] = JNDI name to lookup TM or the method name to retrieve TM instance</li>
056 * <li>info[i][3] = if 'null' an JNDI lookup was made with JNDI name set above, if not null
057 * the class name of the TM factory was assumed and the method name set above will be invoked</li>
058 * </ul>
059 * Example:
060 * <p>
061 * {{"JBoss", "java:/TransactionManager", null}};<br/>
062 * In JBoss we lookup the TM via JNDI, so we don't need a TM factory class.
063 * </p>
064 *
065 * <p>
066 * {{"Websphere 4", TM_DEFAULT_METHOD_NAME, "com.ibm.ejs.jts.jta.JTSXA"},<br/>
067 * {"Websphere 5", TM_DEFAULT_METHOD_NAME, "com.ibm.ejs.jts.jta.TransactionManagerFactory"},<br/>
068 * {"Websphere >5", TM_DEFAULT_METHOD_NAME, "com.ibm.ws.Transaction.TransactionManagerFactory"}};<br/>
069 * In Websphere we have to use a TM factory class and obtain the TM via a <em>getTransactionManager()</em>
070 * method call. The TM factory class is varied in different versions.
071 * </p>
072 */
073 public abstract String[][] getLookupInfo();
074
075 /**
076 * @see org.apache.ojb.broker.transaction.tm.TransactionManagerFactory
077 */
078 public synchronized TransactionManager getTransactionManager() throws TransactionManagerFactoryException
079 {
080 if (tm == null)
081 {
082 StringBuffer msg = new StringBuffer();
083 String[][] lookupInfo = getLookupInfo();
084 String EOL = SystemUtils.LINE_SEPARATOR;
085
086 for (int i = 0; i < lookupInfo.length; i++)
087 {
088 String description = lookupInfo[i][0];
089 String methodName = lookupInfo[i][1];
090 String className = lookupInfo[i][2];
091 try
092 {
093 if (className == null)
094 {
095 tm = jndiLookup(description, methodName);
096 }
097 else
098 {
099 tm = instantiateClass(description, className, methodName);
100 }
101 msg.append("Successfully requested TM for " + description + EOL);
102 }
103 catch (Exception e)
104 {
105 if (className == null)
106 msg.append("Error on TM request for " + description +
107 ", using jndi-lookup '" + methodName + "'" + EOL + e.getMessage() + EOL);
108 else
109 msg.append("Error on TM request for " + description + ", using method '" +
110 methodName + "' for class '" + className + "'" + EOL + e.getMessage() + EOL);
111 }
112 if (tm != null) break;
113 }
114 // if we don't get an TM instance throw exception
115 if (tm == null)
116 {
117 throw new TransactionManagerFactoryException("Can't lookup transaction manager:" + EOL + msg);
118 }
119 }
120 return tm;
121 }
122
123 protected TransactionManager jndiLookup(String description, String methodName)
124 {
125 log.info(description + ", lookup TransactionManager: '" + methodName + "'");
126 return (TransactionManager) NamingLocator.lookup(methodName);
127 }
128
129 protected TransactionManager instantiateClass(String description, String className, String methodName) throws Exception
130 {
131 log.info(description + ", invoke method '"
132 + methodName + "()' on class " + className);
133 Class tmClass = ClassHelper.getClass(className);
134 return (TransactionManager) tmClass.getMethod(methodName, null).invoke(null, null);
135 }
136 }