Java tutorial
/* *Copyright (c) 2005-2010, WSO2 Inc. (http://www.wso2.org) All Rights Reserved. * *WSO2 Inc. licenses this file to you under the Apache License, *Version 2.0 (the "License"); you may not use this file except *in compliance with the License. *You may obtain a copy of the License at * *http://www.apache.org/licenses/LICENSE-2.0 * *Unless required by applicable law or agreed to in writing, *software distributed under the License is distributed on an *"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY *KIND, either express or implied. See the License for the *specific language governing permissions and limitations *under the License. */ package org.wso2.carbon.identity.core.persistence; import org.apache.axiom.om.OMElement; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.wso2.carbon.identity.base.IdentityException; import org.wso2.carbon.identity.base.IdentityRuntimeException; import org.wso2.carbon.identity.core.util.IdentityConfigParser; import org.wso2.carbon.identity.core.util.IdentityCoreConstants; import javax.naming.Context; import javax.naming.InitialContext; import javax.naming.NamingException; import javax.sql.DataSource; import javax.xml.namespace.QName; import java.sql.Connection; import java.sql.SQLException; /** * This class is used for handling identity meta data persistence in the Identity JDBC Store. During * the server start-up, it checks whether the database is created, if not it creates one. It reads * the data source properties from the identity.xml. * This is implemented as a singleton. An instance of this class can be obtained through * JDBCPersistenceManager.getInstance() method. */ public class JDBCPersistenceManager { private static Log log = LogFactory.getLog(JDBCPersistenceManager.class); private static volatile JDBCPersistenceManager instance; private DataSource dataSource; private JDBCPersistenceManager() { initDataSource(); } /** * Get an instance of the JDBCPersistenceManager. It implements a lazy * initialization with double * checked locking, because it is initialized first by identity.core module * during the start up. * * @return JDBCPersistenceManager instance * @throws IdentityException Error when reading the data source configurations */ public static JDBCPersistenceManager getInstance() { if (instance == null) { synchronized (JDBCPersistenceManager.class) { if (instance == null) { instance = new JDBCPersistenceManager(); } } } return instance; } private void initDataSource() { OMElement persistenceManagerConfigElem = IdentityConfigParser.getInstance() .getConfigElement("JDBCPersistenceManager"); try { if (persistenceManagerConfigElem == null) { String errorMsg = "Identity Persistence Manager configuration is not available in " + "identity.xml file. Terminating the JDBC Persistence Manager " + "initialization. This may affect certain functionality."; throw new IdentityRuntimeException(errorMsg); } OMElement dataSourceElem = persistenceManagerConfigElem.getFirstChildWithName( new QName(IdentityCoreConstants.IDENTITY_DEFAULT_NAMESPACE, "DataSource")); if (dataSourceElem == null) { String errorMsg = "DataSource Element is not available for JDBC Persistence " + "Manager in identity.xml file. Terminating the JDBC Persistence Manager " + "initialization. This might affect certain features."; throw new IdentityRuntimeException(errorMsg); } OMElement dataSourceNameElem = dataSourceElem .getFirstChildWithName(new QName(IdentityCoreConstants.IDENTITY_DEFAULT_NAMESPACE, "Name")); if (dataSourceNameElem != null) { String dataSourceName = dataSourceNameElem.getText(); Context ctx = new InitialContext(); dataSource = (DataSource) ctx.lookup(dataSourceName); } } catch (NamingException e) { String errorMsg = "Error when looking up the Identity Data Source."; throw new IdentityRuntimeException(errorMsg, e); } } public void initializeDatabase() { IdentityDBInitializer dbInitializer = new IdentityDBInitializer(dataSource); dbInitializer.createIdentityDatabase(); } /** * Returns an database connection for Identity data source. * * @return Database connection * @throws IdentityException Exception occurred when getting the data source. */ public Connection getDBConnection() throws IdentityRuntimeException { try { Connection dbConnection = dataSource.getConnection(); dbConnection.setAutoCommit(false); dbConnection.setTransactionIsolation(Connection.TRANSACTION_READ_COMMITTED); return dbConnection; } catch (SQLException e) { String errMsg = "Error when getting a database connection object from the Identity data source."; throw new IdentityRuntimeException(errMsg, e); } } }