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Spring Framework example source code file (LocalSessionFactory.java)

This example Spring Framework source code file (LocalSessionFactory.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Spring Framework tags/keywords

class, class, classloader, databaselogin, databasesession, databasesession, object, reflection, sessionfactory, sessionmanager, sql, string, string, toplink, toplink, using, util

The Spring Framework LocalSessionFactory.java source code

/*
 * Copyright 2002-2008 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 org.springframework.orm.toplink;

import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Map;
import java.util.Properties;

import javax.sql.DataSource;

import oracle.toplink.exceptions.TopLinkException;
import oracle.toplink.internal.databaseaccess.DatabasePlatform;
import oracle.toplink.jndi.JNDIConnector;
import oracle.toplink.sessionbroker.SessionBroker;
import oracle.toplink.sessions.DatabaseLogin;
import oracle.toplink.sessions.DatabaseSession;
import oracle.toplink.sessions.SessionLog;
import oracle.toplink.threetier.ServerSession;
import oracle.toplink.tools.sessionconfiguration.XMLLoader;
import oracle.toplink.tools.sessionmanagement.SessionManager;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.springframework.beans.PropertyAccessorFactory;
import org.springframework.util.ClassUtils;
import org.springframework.util.CollectionUtils;
import org.springframework.util.ReflectionUtils;

/**
 * Convenient JavaBean-style factory for a TopLink SessionFactory instance.
 * Loads a TopLink <code>sessions.xml file from the class path, exposing a
 * specific TopLink Session defined there (usually a ServerSession).
 *
 * <p>TopLink Session configuration is done using a sessions.xml file.
 * The most convenient way to create the <code>sessions.xml file is to use
 * the Oracle TopLink SessionsEditor workbench. The <code>sessions.xml file
 * contains all runtime configuration and points to a second XML or Class resource
 * from which to load the actual TopLink project metadata (which defines mappings).
 *
 * <p>LocalSessionFactory loads the sessions.xml file during
 * initialization in order to bootstrap the specified TopLink (Server)Session.
 * The name of the actual config resource and the name of the Session to be loaded,
 * if different from <code>sessions.xml and "Session", respectively, can be
 * configured through bean properties.
 *
 * <p>All resources (sessions.xml and Mapping Workbench metadata) are
 * loaded using <code>ClassLoader.getResourceAsStream calls by TopLink, so
 * users may need to configure a ClassLoader with appropriate visibility. This is
 * particularly important in J2EE environments where the TopLink metadata might be
 * deployed to a different location than the Spring configuration. The ClassLoader
 * used to search for the TopLink metadata and to load the persistent classes
 * defined there will default to the the context ClassLoader for the current Thread.
 *
 * <p>TopLink's debug logging can be redirected to Commons Logging by passing a
 * CommonsLoggingSessionLog to the "sessionLog" bean property. Otherwise, TopLink
 * uses it's own DefaultSessionLog, whose levels are configured in the
 * <code>sessions.xml file.
 *
 * <p>This class has been tested against both TopLink 9.0.4 and TopLink 10.1.3.
 * It will automatically adapt to the TopLink version encountered: for example,
 * using an XMLSessionConfigLoader on 10.1.3, but an XMLLoader on 9.0.4.
 *
 * <p>NOTE: When defining a TopLink SessionFactory in a Spring application
 * context, you will usually define a bean of type <b>LocalSessionFactoryBean.
 * LocalSessionFactoryBean is a subclass of this factory, which will automatically
 * expose the created TopLink SessionFactory instance as bean reference.
 *
 * @author Juergen Hoeller
 * @author <a href="mailto:james.x.clark@oracle.com">James Clark
 * @since 1.2
 * @see LocalSessionFactoryBean
 * @see TopLinkTemplate#setSessionFactory
 * @see TopLinkTransactionManager#setSessionFactory
 * @see SingleSessionFactory
 * @see ServerSessionFactory
 * @see oracle.toplink.threetier.ServerSession
 * @see oracle.toplink.tools.sessionconfiguration.XMLLoader
 * @see oracle.toplink.tools.sessionconfiguration.XMLSessionConfigLoader
 */
public class LocalSessionFactory {

	/**
	 * The default location of the <code>sessions.xml TopLink configuration file:
	 * "sessions.xml" in the class path.
	 */
	public static final String DEFAULT_SESSIONS_XML = "sessions.xml";

	/**
	 * The default session name to look for in the sessions.xml: "Session".
	 */
	public static final String DEFAULT_SESSION_NAME = "Session";


	protected final Log logger = LogFactory.getLog(getClass());

	/**
	 * The classpath location of the sessions TopLink configuration file.
	 */
	private String configLocation = DEFAULT_SESSIONS_XML;

	/**
	 * The session name to look for in the sessions.xml configuration file.
	 */
	private String sessionName = DEFAULT_SESSION_NAME;

	/**
	 * The ClassLoader to use to load the sessions.xml and project XML files.
	 */
	private ClassLoader sessionClassLoader;

	private DatabaseLogin databaseLogin;

	private final Map loginPropertyMap = new HashMap();

	private DataSource dataSource;

	private DatabasePlatform databasePlatform;

	private SessionLog sessionLog;


	/**
	 * Set the TopLink <code>sessions.xml configuration file that defines
	 * TopLink Sessions, as class path resource location.
	 * <p>The sessions.xml file will usually be placed in the META-INF
	 * directory or root path of a JAR file, or the <code>WEB-INF/classes
	 * directory of a WAR file (specifying "META-INF/toplink-sessions.xml" or
	 * simply "toplink-sessions.xml" as config location, respectively).
	 * <p>The default config location is "sessions.xml" in the root of the class path.
	 * @param configLocation the class path location of the <code>sessions.xml file
	 */
	public void setConfigLocation(String configLocation) {
		this.configLocation = configLocation;
	}

	/**
	 * Set the name of the TopLink Session, as defined in TopLink's
	 * <code>sessions.xml configuration file.
	 * The default session name is "Session".
	 */
	public void setSessionName(String sessionName) {
		this.sessionName = sessionName;
	}

	/**
	 * Set the ClassLoader that should be used to lookup the config resources.
	 * If nothing is set here, then we will try to use the Thread context ClassLoader
	 * and the ClassLoader that loaded this factory class, in that order.
	 * <p>This ClassLoader will be used to load the TopLink configuration files
	 * and the project metadata. Furthermore, the TopLink ConversionManager will
	 * use this ClassLoader to load all TopLink entity classes. If the latter is not
	 * appropriate, users can configure a pre-login SessionEvent to alter the
	 * ConversionManager ClassLoader that TopLink will use at runtime.
	 */
	public void setSessionClassLoader(ClassLoader sessionClassLoader) {
		this.sessionClassLoader = sessionClassLoader;
	}

	/**
	 * Specify the DatabaseLogin instance that carries the TopLink database
	 * configuration to use. This is an alternative to specifying that information
	 * in a <login> tag in the <code>sessions.xml configuration file,
	 * allowing for configuring a DatabaseLogin instance as standard Spring bean
	 * definition (being able to leverage Spring's placeholder mechanism, etc).
	 * <p>The DatabaseLogin instance can either carry traditional JDBC config properties
	 * or hold a nested TopLink Connector instance, pointing to the connection pool to use.
	 * DatabaseLogin also holds the TopLink DatabasePlatform instance that defines the
	 * database product that TopLink is talking to (for example, HSQLPlatform).
	 * <p>WARNING: Overriding the Login instance has been reported to not
	 * work on TopLink 10.1.3.0 and 10.1.3.1. Specify {@link #setLoginProperties
	 * "loginProperties"} or {@link #getLoginPropertyMap "loginPropertyMap[...]"}
	 * entries instead, if you prefer to have the login configuration defined
	 * on the Spring LocalSessionFactory.
	 */
	public void setDatabaseLogin(DatabaseLogin databaseLogin) {
		this.databaseLogin = databaseLogin;
	}

	/**
	 * Specify TopLink login properties, to be passed to
	 * the {@link oracle.toplink.sessions.DatabaseLogin} instance.
	 * <p>Can be populated with a String "value" (parsed via PropertiesEditor)
	 * or a "props" element in XML bean definitions.
	 * @see oracle.toplink.sessions.DatabaseLogin
	 */
	public void setLoginProperties(Properties loginProperties) {
		CollectionUtils.mergePropertiesIntoMap(loginProperties, this.loginPropertyMap);
	}

	/**
	 * Specify TopLink login properties as a Map, to be passed to
	 * the {@link oracle.toplink.sessions.DatabaseLogin} instance.
	 * <p>Can be populated with a "map" or "props" element in XML bean definitions.
	 * @see oracle.toplink.sessions.DatabaseLogin
	 */
	public void setLoginPropertyMap(Map loginProperties) {
		if (loginProperties != null) {
			this.loginPropertyMap.putAll(loginProperties);
		}
	}

	/**
	 * Allow Map access to the TopLink login properties to be passed to the
	 * DatabaseLogin instance, with the option to add or override specific entries.
	 * <p>Useful for specifying entries directly, for example via
	 * "loginPropertyMap[tableQualifier]".
	 * @see oracle.toplink.sessions.DatabaseLogin
	 */
	public Map getLoginPropertyMap() {
		return this.loginPropertyMap;
	}

	/**
	 * Specify a standard JDBC DataSource that TopLink should use as connection pool.
	 * This allows for using a shared DataSource definition instead of TopLink's
	 * own connection pool.
	 * <p>A passed-in DataSource will be wrapped in an appropriate TopLink Connector
	 * and registered with the TopLink DatabaseLogin instance (either the default
	 * instance or one passed in through the "databaseLogin" property). The
	 * "usesExternalConnectionPooling" flag will automatically be set to "true".
	 * @see oracle.toplink.sessions.DatabaseLogin#setConnector(oracle.toplink.sessions.Connector)
	 * @see oracle.toplink.sessions.DatabaseLogin#setUsesExternalConnectionPooling(boolean)
	 * @see #setDatabaseLogin(oracle.toplink.sessions.DatabaseLogin)
	 */
	public void setDataSource(DataSource dataSource) {
		this.dataSource = dataSource;
	}

	/**
	 * Specify the TopLink DatabasePlatform instance that the Session should use:
	 * for example, HSQLPlatform. This is an alternative to specifying the platform
	 * in a <login> tag in the <code>sessions.xml configuration file.
	 * <p>A passed-in DatabasePlatform will be registered with the TopLink
	 * DatabaseLogin instance (either the default instance or one passed in
	 * through the "databaseLogin" property).
	 * @see oracle.toplink.internal.databaseaccess.HSQLPlatform
	 * @see oracle.toplink.platform.database.HSQLPlatform
	 */
	public void setDatabasePlatform(DatabasePlatform databasePlatform) {
		this.databasePlatform = databasePlatform;
	}

	/**
	 * Specify a TopLink SessionLog instance to use for detailed logging of the
	 * Session's activities: for example, DefaultSessionLog (which logs to the
	 * console), JavaLog (which logs through JDK 1.4'S <code>java.util.logging,
	 * available as of TopLink 10.1.3), or CommonsLoggingSessionLog /
	 * CommonsLoggingSessionLog904 (which logs through Commons Logging,
	 * on TopLink 10.1.3 and 9.0.4, respectively).
	 * <p>Note that detailed Session logging is usually only useful for debug
	 * logging, with adjustable detail level. As of TopLink 10.1.3, TopLink also
	 * uses different log categories, which allows for fine-grained filtering of
	 * log messages. For standard execution, no SessionLog needs to be specified.
	 * @see oracle.toplink.sessions.DefaultSessionLog
	 * @see oracle.toplink.logging.DefaultSessionLog
	 * @see oracle.toplink.logging.JavaLog
	 * @see org.springframework.orm.toplink.support.CommonsLoggingSessionLog
	 * @see org.springframework.orm.toplink.support.CommonsLoggingSessionLog904
	 */
	public void setSessionLog(SessionLog sessionLog) {
		this.sessionLog = sessionLog;
	}


	/**
	 * Create a TopLink SessionFactory according to the configuration settings.
	 * @return the new TopLink SessionFactory
	 * @throws TopLinkException in case of errors
	 */
	public SessionFactory createSessionFactory() throws TopLinkException {
		if (logger.isInfoEnabled()) {
			logger.info("Initializing TopLink SessionFactory from [" + this.configLocation + "]");
		}

		// Determine class loader to use.
		ClassLoader classLoader =
				(this.sessionClassLoader != null ? this.sessionClassLoader : ClassUtils.getDefaultClassLoader());

		// Initialize the TopLink Session, using the configuration file
		// and the session name.
		DatabaseSession session = loadDatabaseSession(this.configLocation, this.sessionName, classLoader);

		// It is possible for SessionManager to return a null Session!
		if (session == null) {
			throw new IllegalStateException(
					"A session named '" + this.sessionName + "' could not be loaded from resource [" +
					this.configLocation + "] using ClassLoader [" + classLoader + "]. " +
					"This is most likely a deployment issue: Can the class loader access the resource?");
		}

		DatabaseLogin login = (this.databaseLogin != null ? this.databaseLogin : session.getLogin());

		// Apply specified login properties to the DatabaseLogin instance.
		if (this.loginPropertyMap != null) {
			PropertyAccessorFactory.forBeanPropertyAccess(login).setPropertyValues(this.loginPropertyMap);
		}

		// Override default connection pool with specified DataSource, if any.
		if (this.dataSource != null) {
			login.setConnector(new JNDIConnector(this.dataSource));
			login.setUsesExternalConnectionPooling(true);
		}

		// Override default DatabasePlatform with specified one, if any.
		if (this.databasePlatform != null) {
			login.usePlatform(this.databasePlatform);
		}

		// Override default DatabaseLogin instance with specified one, if any.
		if (this.databaseLogin != null) {
			setDatabaseLogin(session, this.databaseLogin);
		}

		// Override default SessionLog with specified one, if any.
		if (this.sessionLog != null) {
			session.setSessionLog(this.sessionLog);
			session.logMessages();
		}

		// Log in and create corresponding SessionFactory.
		session.login();
		return newSessionFactory(session);
	}

	/**
	 * Handle differences between the <code>Session.setLogin interface
	 * between TopLink 9.0.4 to 10.1.3.
	 * <p>The Login interface was introduced in TopLink 10.1.3.
	 * @param session the DatabaseSession being logged in
	 * @param login the DatabaseLogin injected by Spring
	 * @see oracle.toplink.sessions.DatabaseSession#setLogin
	 */
	protected void setDatabaseLogin(DatabaseSession session, DatabaseLogin login) {
		Method setLoginMethod = null;
		try {
			// Search for the new 10.1.3 Login interface...
			Class loginClass = DatabaseSession.class.getClassLoader().loadClass("oracle.toplink.sessions.Login");
			setLoginMethod = DatabaseSession.class.getMethod("setLogin", new Class[] {loginClass});
			if (logger.isDebugEnabled()) {
				logger.debug("Using TopLink 10.1.3 setLogin(Login) API");
			}
		}
		catch (Exception ex) {
			// TopLink 10.1.3 Login interface not found ->
			// fall back to TopLink 9.0.4's setLogin(DatabaseLogin)
			if (logger.isDebugEnabled()) {
				logger.debug("Using TopLink 9.0.4 setLogin(DatabaseLogin) API");
			}
			session.setLogin(login);
			return;
		}

		// Invoke the 10.1.3 version: Session.setLogin(Login)
		ReflectionUtils.invokeMethod(setLoginMethod, session, new Object[] {login});
	}

	/**
	 * Load the specified DatabaseSession from the TopLink <code>sessions.xml
	 * configuration file.
	 * @param configLocation the class path location of the <code>sessions.xml file
	 * @param sessionName the name of the TopLink Session in the configuration file
	 * @param sessionClassLoader the class loader to use
	 * @return the DatabaseSession instance
	 * @throws TopLinkException in case of errors
	 */
	protected DatabaseSession loadDatabaseSession(
			String configLocation, String sessionName, ClassLoader sessionClassLoader)
			throws TopLinkException {

		SessionManager manager = getSessionManager();

		// Try to find TopLink 10.1.3 XMLSessionConfigLoader.
		Method getSessionMethod = null;
		Object loader = null;
		try {
			Class loaderClass = SessionManager.class.getClassLoader().loadClass(
					"oracle.toplink.tools.sessionconfiguration.XMLSessionConfigLoader");
			getSessionMethod = SessionManager.class.getMethod("getSession",
					new Class[] {loaderClass, String.class, ClassLoader.class, boolean.class, boolean.class, boolean.class});
			if (logger.isDebugEnabled()) {
				logger.debug("Using TopLink 10.1.3 XMLSessionConfigLoader");
			}
			Constructor ctor = loaderClass.getConstructor(new Class[] {String.class});
			loader = ctor.newInstance(new Object[] {configLocation});
		}
		catch (Exception ex) {
			// TopLink 10.1.3 XMLSessionConfigLoader not found ->
			// fall back to TopLink 9.0.4 XMLLoader.
			if (logger.isDebugEnabled()) {
				logger.debug("Using TopLink 9.0.4 XMLLoader");
			}
			XMLLoader xmlLoader = new XMLLoader(configLocation);
			return (DatabaseSession) manager.getSession(xmlLoader, sessionName, sessionClassLoader, false, false);
		}

		// TopLink 10.1.3 XMLSessionConfigLoader found -> create loader instance
		// through reflection and fetch specified Session from SessionManager.
		// This invocation will check if the ClassLoader passed in is the same
		// as the one used to a session currently loaded with the same "sessionName"
		// If the ClassLoaders are different, then this LocalSessionFactory is being
		// re-loaded after a hot-deploy and the existing DatabaseSession will be logged
		// out and re-built from scratch.
		return (DatabaseSession) ReflectionUtils.invokeMethod(getSessionMethod, manager,
				new Object[] {loader, sessionName, sessionClassLoader, Boolean.FALSE, Boolean.FALSE, Boolean.TRUE});
	}

	/**
	 * Return the TopLink SessionManager to use for loading DatabaseSessions.
	 * <p>The default implementation creates a new plain SessionManager instance,
	 * leading to completely independent TopLink Session instances. Could be
	 * overridden to return a shared or pre-configured SessionManager.
	 * @return the TopLink SessionManager instance
	 */
	protected SessionManager getSessionManager() {
		return new SessionManager();
	}

	/**
	 * Create a new SessionFactory for the given TopLink DatabaseSession.
	 * <p>The default implementation creates a ServerSessionFactory for a
	 * ServerSession and a SingleSessionFactory for a plain DatabaseSession.
	 * @param session the TopLink DatabaseSession to create a SessionFactory for
	 * @return the SessionFactory
	 * @throws TopLinkException in case of errors
	 * @see ServerSessionFactory
	 * @see SingleSessionFactory
	 * @see oracle.toplink.threetier.ServerSession
	 * @see oracle.toplink.sessions.DatabaseSession
	 */
	protected SessionFactory newSessionFactory(DatabaseSession session) {
		if (session instanceof ServerSession) {
			return new ServerSessionFactory((ServerSession) session);
		}
		else if (session instanceof SessionBroker) {
			return new SessionBrokerSessionFactory((SessionBroker) session);
		}
		else {
			return new SingleSessionFactory(session);
		}
	}

}

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