/**
* Licensed to Jasig under one or more contributor license
* agreements. See the NOTICE file distributed with this work
* for additional information regarding copyright ownership.
* Jasig 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.jasig.portal.spring;
import javax.servlet.ServletContext;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.jasig.portal.utils.threading.SingletonDoubleCheckedCreator;
import org.springframework.beans.factory.xml.XmlBeanDefinitionReader;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.support.GenericApplicationContext;
import org.springframework.web.context.WebApplicationContext;
import org.springframework.web.context.support.WebApplicationContextUtils;
/**
* Provides standard access to the portal's {@link ApplicationContext}. If running in a web application a
* {@link WebApplicationContext} is available.
*
* {@link #getApplicationContext()} should be used by most uPortal code that needs access to the portal's
* {@link ApplicationContext}. It ensures that a single {@link ApplicationContext} is used portal-wide both
* when the portal is running as a web-application and when tools are run from the command line.
*
* For legacy portal code that is not yet Spring managed and does not have access to the {@link ServletContext} this
* class provides similar functionality to {@link WebApplicationContextUtils} via the
* {@link #getWebApplicationContext()} and {@link #getRequiredWebApplicationContext()}. These methods are deprecated as
* any code that requires a {@link WebApplicationContext} should either be refactored as a Spring managed bean or have
* access to the {@link ServletContext}
*
* @author Eric Dalquist
* @version $Revision$
*/
public class PortalApplicationContextLocator implements ServletContextListener {
private static Log LOGGER = LogFactory.getLog(PortalApplicationContextLocator.class);
private static final SingletonDoubleCheckedCreator<ConfigurableApplicationContext> applicationContextCreator = new PortalApplicationContextCreator();
private static Throwable directCreatorThrowable;
private static ServletContext servletContext;
/* (non-Javadoc)
* @see javax.servlet.ServletContextListener#contextInitialized(javax.servlet.ServletContextEvent)
*/
public void contextInitialized(ServletContextEvent sce) {
servletContext = sce.getServletContext();
}
/* (non-Javadoc)
* @see javax.servlet.ServletContextListener#contextDestroyed(javax.servlet.ServletContextEvent)
*/
public void contextDestroyed(ServletContextEvent sce) {
servletContext = null;
}
/**
* @return <code>true</code> if a WebApplicationContext is available, <code>false</code> if only an ApplicationContext is available
* @deprecated Only needed for using {@link #getRequiredWebApplicationContext()} or {@link #getWebApplicationContext()}.
*/
@Deprecated
public static boolean isRunningInWebApplication() {
return servletContext != null;
}
/**
* @return The WebApplicationContext for the portal
* @throws IllegalStateException if no ServletContext is available to retrieve a WebApplicationContext for or if the root WebApplicationContext could not be found
* @deprecated This method is a work-around for areas in uPortal that do not have the ability to use the {@link WebApplicationContextUtils#getRequiredWebApplicationContext(ServletContext)} directly.
*/
@Deprecated
public static WebApplicationContext getRequiredWebApplicationContext() {
final ServletContext context = servletContext;
if (context == null) {
throw new IllegalStateException("No ServletContext is available to load a WebApplicationContext for. Is this ServletContextListener not configured or has the ServletContext been destroyed?");
}
return WebApplicationContextUtils.getRequiredWebApplicationContext(context);
}
/**
* @return The WebApplicationContext for the portal, null if no ServletContext is available
* @deprecated This method is a work-around for areas in uPortal that do not have the ability to use the {@link WebApplicationContextUtils#getWebApplicationContext(ServletContext)} directly.
*/
@Deprecated
public static WebApplicationContext getWebApplicationContext() {
final ServletContext context = servletContext;
if (context == null) {
return null;
}
return WebApplicationContextUtils.getWebApplicationContext(context);
}
/**
* If running in a web application the existing {@link WebApplicationContext} will be returned. if
* not a singleton {@link ApplicationContext} is created if needed and returned. Unless a {@link WebApplicationContext}
* is specifically needed this method should be used as it will work both when running in and out
* of a web application
*
* @return The {@link ApplicationContext} for the portal.
*/
public static ApplicationContext getApplicationContext() {
final ServletContext context = servletContext;
if (context != null) {
LOGGER.debug("Using WebApplicationContext");
if (applicationContextCreator.isCreated()) {
final IllegalStateException createException = new IllegalStateException("A portal managed ApplicationContext has already been created but now a ServletContext is available and a WebApplicationContext will be returned. " +
"This situation should be resolved by delaying calls to this class until after the web-application has completely initialized.");
LOGGER.error(createException, createException);
LOGGER.error("Stack trace of original ApplicationContext creator", directCreatorThrowable);
throw createException;
}
final WebApplicationContext webApplicationContext = WebApplicationContextUtils.getWebApplicationContext(context);
if (webApplicationContext == null) {
throw new IllegalStateException("ServletContext is available but WebApplicationContextUtils.getWebApplicationContext(ServletContext) returned null. Either the application context failed to load or is not yet done loading.");
}
return webApplicationContext;
}
return applicationContextCreator.get();
}
/**
* If the ApplicationContext returned by {@link #getApplicationContext()} is 'portal managed' the shutdown hook
* for the context is called, closing and cleaning up all spring managed resources.
*
* If the ApplicationContext returned by {@link #getApplicationContext()} is actually a WebApplicationContext
* this method does nothing but log an error message.
*/
public static void shutdown() {
if (applicationContextCreator.isCreated()) {
final ConfigurableApplicationContext applicationContext = applicationContextCreator.get();
applicationContext.close();
}
else {
final IllegalStateException createException = new IllegalStateException("No portal managed ApplicationContext has been created, there is nothing to shutdown.");
LOGGER.error(createException, createException);
}
}
/**
* Creator class that knows how to instantiate the lazily initialized portal application context if needed
*/
private static class PortalApplicationContextCreator extends SingletonDoubleCheckedCreator<ConfigurableApplicationContext> {
@Override
protected ConfigurableApplicationContext createSingleton(Object... args) {
LOGGER.info("Creating new lazily initialized GenericApplicationContext for the portal");
final long startTime = System.currentTimeMillis();
final GenericApplicationContext genericApplicationContext = new GenericApplicationContext();
final XmlBeanDefinitionReader reader = new XmlBeanDefinitionReader(genericApplicationContext);
reader.setDocumentReaderClass(LazyInitByDefaultBeanDefinitionDocumentReader.class);
reader.loadBeanDefinitions("/properties/contexts/*.xml");
genericApplicationContext.refresh();
genericApplicationContext.registerShutdownHook();
directCreatorThrowable = new Throwable();
directCreatorThrowable.fillInStackTrace();
LOGGER.info("Created new lazily initialized GenericApplicationContext for the portal in " + (System.currentTimeMillis() - startTime) + "ms");
return genericApplicationContext;
}
}
}