Java tutorial
/* * Copyright 2002-2005 the original author or authors. * * 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 info.jtrac.config; import java.sql.Connection; import java.sql.Statement; import javax.sql.DataSource; import org.apache.commons.dbcp.BasicDataSource; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.beans.factory.DisposableBean; import org.springframework.beans.factory.FactoryBean; import org.springframework.jdbc.datasource.SingleConnectionDataSource; import org.springframework.jndi.JndiObjectFactoryBean; import org.springframework.util.StringUtils; /** * <p> * This class implements the Spring frameworks * {@link org.springframework.beans.factory.FactoryBean} as well as the * {@link org.springframework.beans.factory.DisposableBean} to conditionally * create the correct <code>DataSource</code> object to access the database. * </p> * * Supported data sources are: * <ul> * <li><a href="http://hsqldb.org/">HSQLDB (embedded)</a></li> * <li><a href="http://commons.apache.org/dbcp/">Apache DBCP</a></li> * <li>Java Naming and Directory Interface (JNDI); supported by most JDBC * database drivers</li> * </ul> */ public class DataSourceFactoryBean implements FactoryBean<DataSource>, DisposableBean { /** * Logger object */ private final Logger logger = LoggerFactory.getLogger(getClass()); /** * DB driver class name */ private String driverClassName; /** * DB url */ private String url; /** * DB user */ private String username; /** * DB password */ private String password; /** * DB queries used to check if the database can be accessed */ private String validationQuery; /** * DB JNDI data source name */ private String dataSourceJndiName; /** * DB JNDI data source object */ private DataSource dataSource; /** * This method allows to store the name of the DB driver class. * * @param driverClassName The name of the DB driver class. */ public void setDriverClassName(String driverClassName) { this.driverClassName = driverClassName; } /** * This method allows to store the DB url. * * @param url The DB url. */ public void setUrl(String url) { this.url = url; } /** * This method allows to store the DB user. * * @param username The DB user. */ public void setUsername(String username) { this.username = username; } /** * This method allows to store the DB password. * * @param password The DB password. */ public void setPassword(String password) { this.password = password; } /** * This method allows to store the SQL query string used to check if * the DB connection is working. * * @param validationQuery The SQL query used to validate if the DB * connection is working. */ public void setValidationQuery(String validationQuery) { this.validationQuery = validationQuery; } /** * This method allows to store the JNDI data source name. * * @param dataSourceJndiName The JNDI data source name. */ public void setDataSourceJndiName(String dataSourceJndiName) { this.dataSourceJndiName = dataSourceJndiName; } /** * This method returns the dataSource object used for the DB access. * * @throws Exception * @see org.springframework.beans.factory.FactoryBean#getObject() */ @Override public DataSource getObject() throws Exception { if (StringUtils.hasText(dataSourceJndiName)) { logger.info("JNDI datasource requested, looking up datasource from JNDI name: '" + dataSourceJndiName + "'"); JndiObjectFactoryBean factoryBean = new JndiObjectFactoryBean(); factoryBean.setJndiName(dataSourceJndiName); // "java:comp/env/" will be prefixed if the JNDI name doesn't already have it factoryBean.setResourceRef(true); // This step actually does the JNDI lookup try { factoryBean.afterPropertiesSet(); } catch (Exception e) { logger.error("datasource init from JNDI failed : " + e); logger.error("aborting application startup"); throw new RuntimeException(e); } // end try..catch dataSource = (DataSource) factoryBean.getObject(); } else if (url.startsWith("jdbc:hsqldb:file")) { logger.info("embedded HSQLDB mode detected, switching on spring single connection data source"); SingleConnectionDataSource ds = new SingleConnectionDataSource(); ds.setUrl(url); ds.setDriverClassName(driverClassName); ds.setUsername(username); ds.setPassword(password); ds.setSuppressClose(true); dataSource = ds; } else { logger.info( "Not using embedded HSQLDB or JNDI datasource, switching on Apache DBCP data source connection pooling"); BasicDataSource ds = new BasicDataSource(); ds.setUrl(url); ds.setDriverClassName(driverClassName); ds.setUsername(username); ds.setPassword(password); ds.setValidationQuery(validationQuery); ds.setTestOnBorrow(false); ds.setTestWhileIdle(true); ds.setTimeBetweenEvictionRunsMillis(600000); dataSource = ds; } // end if..else return dataSource; } /** * This method returns the class name of the DataSource object which can be * used to determine which data source implementation is currently used. * * @return Returns the class name <code>Object.class</code> of the * DataSource object. * @see org.springframework.beans.factory.FactoryBean#getObjectType() */ @Override public Class<DataSource> getObjectType() { return DataSource.class; } /** * This method returns if the factory is implemented as Singleton. * * @return Returns if the factory is implemented as Singleton or not. * @see org.springframework.beans.factory.FactoryBean#isSingleton() */ @Override public boolean isSingleton() { return true; } /** * This method is called to clean up the references when the object is * destroyed. * * @throws Exception * @see org.springframework.beans.factory.DisposableBean#destroy() */ @Override public void destroy() throws Exception { if (dataSource instanceof SingleConnectionDataSource) { logger.info("attempting to shut down embedded HSQLDB database"); Connection con = dataSource.getConnection(); Statement stmt = con.createStatement(); stmt.executeUpdate("SHUTDOWN"); stmt.close(); con.close(); logger.info("embedded HSQLDB database shut down successfully"); } else if (dataSource instanceof BasicDataSource) { logger.info("attempting to close Apache DBCP data source"); ((BasicDataSource) dataSource).close(); logger.info("Apache DBCP data source closed successfully"); } else { logger.info("context shutting down for JNDI datasource"); } // end if..else } }