Java tutorial
/* * Copyright (c) 2011, WSO2 Inc. (http://www.wso2.org) All Rights Reserved. * * Licensed 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.humantask.core.db; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.wso2.carbon.humantask.core.configuration.HumanTaskServerConfiguration; import org.wso2.carbon.humantask.core.dao.Constants; import org.wso2.carbon.humantask.core.dao.HumanTaskDAOConnectionFactoryJDBC; import org.wso2.carbon.humantask.core.engine.HumanTaskServerException; import org.wso2.carbon.humantask.core.utils.HumanTaskDatabaseCreator; import javax.naming.Context; import javax.naming.InitialContext; import javax.sql.DataSource; import javax.transaction.TransactionManager; import java.util.HashMap; import java.util.Map; import java.util.Properties; /** * Internal representation of the human task database. */ public class Database { private static final Log log = LogFactory.getLog(Database.class); private HumanTaskServerConfiguration serverConfiguration; /* A flag indicating whether the database is already initiated */ private boolean started; private TransactionManager tnxManager; private DataSource dataSource; /** * @return The Human Task DataSource.. */ public synchronized DataSource getDataSource() { if (this.dataSource == null) { throw new RuntimeException("Human Task Database is not properly initialised!"); } return this.dataSource; } public Database(HumanTaskServerConfiguration htConfig) { if (htConfig == null) { throw new IllegalArgumentException("Must provide the human task server configuration!"); } this.serverConfiguration = htConfig; } /** * Database initialization logic. */ public synchronized void start() throws DatabaseConfigurationException, HumanTaskServerException { if (started) { return; } this.dataSource = null; initDataSource(); setupHumanTaskDatabase(); } private void setupHumanTaskDatabase() throws HumanTaskServerException { if (System.getProperty("setup") != null) { HumanTaskDatabaseCreator humantaskDBCreator; try { humantaskDBCreator = new HumanTaskDatabaseCreator(getDataSource()); } catch (Exception e) { String errMsg = "Error creating HumanTaskDatabaseCreator"; log.error(errMsg, e); throw new HumanTaskServerException(errMsg, e); } if (!humantaskDBCreator.isDatabaseStructureCreated("SELECT * FROM HT_JOB")) { try { //TODO rename following method humantaskDBCreator.createRegistryDatabase(); } catch (Exception e) { String errMsg = "Error creating HumanTask database"; log.error(errMsg, e); throw new HumanTaskServerException(errMsg, e); } } else { if (log.isDebugEnabled()) { log.debug("HumanTask database already exists. Using the old database."); } } } } /** * Shut down logic for the Database related resources. */ public synchronized void shutdown() { if (!started) { return; } this.dataSource = null; this.started = false; } private void initDataSource() throws DatabaseConfigurationException { //Note : We can improve this to consider internal/external databases. initExternalDb(); } private void initExternalDb() throws DatabaseConfigurationException { try { this.dataSource = (DataSource) lookupInJndi(serverConfiguration.getDataSourceName()); if (log.isDebugEnabled()) { log.debug("HumanTask Server using external DataSource " + serverConfiguration.getDataSourceName()); } } catch (Exception e) { String errorMsg = "Failed to resolved external DataSource at " + serverConfiguration.getDataSourceName(); log.error(errorMsg, e); throw new DatabaseConfigurationException(errorMsg, e); } } @SuppressWarnings("unchecked") private <T> T lookupInJndi(String objName) throws Exception { ClassLoader old = Thread.currentThread().getContextClassLoader(); Thread.currentThread().setContextClassLoader(getClass().getClassLoader()); try { InitialContext ctx = null; try { if (serverConfiguration.getDataSourceJNDIRepoInitialContextFactory() != null && serverConfiguration.getDataSourceJNDIRepoProviderURL() != null) { Properties jndiProps = new Properties(); jndiProps.setProperty(Context.INITIAL_CONTEXT_FACTORY, serverConfiguration.getDataSourceJNDIRepoInitialContextFactory()); jndiProps.setProperty(Context.PROVIDER_URL, serverConfiguration.getDataSourceJNDIRepoProviderURL()); ctx = new InitialContext(jndiProps); } else { ctx = new InitialContext(); } return (T) ctx.lookup(objName); } finally { if (ctx != null) { try { ctx.close(); } catch (Exception ex1) { log.error("Error closing JNDI connection.", ex1); } } } } finally { Thread.currentThread().setContextClassLoader(old); } } /** * * @param tnxManager : The transaction manager to set. */ public void setTransactionManager(TransactionManager tnxManager) { this.tnxManager = tnxManager; } /** * Creates the DAO connection factory. * @return : the connection factory. * @throws DatabaseConfigurationException : If the provided config factory cannot be instantiated. */ public HumanTaskDAOConnectionFactoryJDBC createDAOConnectionFactory() throws DatabaseConfigurationException { String connectionFactoryClassName = serverConfiguration.getDaoConnectionFactoryClass(); if (log.isDebugEnabled()) { log.debug("Using DAO connection factory class: " + connectionFactoryClassName); } HumanTaskDAOConnectionFactoryJDBC humanTaskDAOConnectionFactoryJDBC; try { humanTaskDAOConnectionFactoryJDBC = (HumanTaskDAOConnectionFactoryJDBC) Class .forName(connectionFactoryClassName).newInstance(); } catch (Exception ex) { String errMsg = "Human Task DAO Connection Factory instantiation failed!"; log.error(errMsg); throw new DatabaseConfigurationException(errMsg, ex); } humanTaskDAOConnectionFactoryJDBC.setDataSource(getDataSource()); humanTaskDAOConnectionFactoryJDBC.setTransactionManager(getTnxManager()); humanTaskDAOConnectionFactoryJDBC.setDAOConnectionFactoryProperties(getGenericDAOFactoryProperties()); humanTaskDAOConnectionFactoryJDBC.init(); return humanTaskDAOConnectionFactoryJDBC; } /** * Gets the generic properties for DAO Connection Factory. * @return */ private Map<String, Object> getGenericDAOFactoryProperties() { Map<String, Object> daoFactoryProperties = new HashMap<String, Object>(); daoFactoryProperties.put(Constants.DATA_SOURCE_PROP, getDataSource()); daoFactoryProperties.put(Constants.PROP_ENABLE_DDL_GENERATION, serverConfiguration.isGenerateDdl()); daoFactoryProperties.put(Constants.PROP_ENABLE_SQL_TRACING, serverConfiguration.isShowSql()); daoFactoryProperties.put(Constants.DAO_FACTORY_CLASS_PROP, serverConfiguration.getDaoConnectionFactoryClass()); return daoFactoryProperties; } public TransactionManager getTnxManager() { return tnxManager; } }