Java tutorial
/* * (C) Copyright 2013 Kurento (http://kurento.org/) * * All rights reserved. This program and the accompanying materials * are made available under the terms of the GNU Lesser General Public License * (LGPL) version 2.1 which accompanies this distribution, and is available at * http://www.gnu.org/licenses/lgpl-2.1.html * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * */ package com.kurento.kmf.spring; import java.io.File; import java.io.FileInputStream; import java.io.IOException; import java.io.InputStream; import java.util.Properties; import java.util.concurrent.ConcurrentHashMap; import javax.servlet.ServletContext; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor; import org.springframework.beans.factory.config.PropertyOverrideConfigurer; import org.springframework.beans.factory.support.GenericBeanDefinition; import org.springframework.context.annotation.AnnotationConfigApplicationContext; import org.springframework.util.Assert; import org.springframework.web.context.WebApplicationContext; import org.springframework.web.context.support.ServletContextResource; import org.springframework.web.context.support.WebApplicationContextUtils; public final class KurentoApplicationContextUtils { private static final Logger log = LoggerFactory.getLogger(KurentoApplicationContextUtils.class); private static final String KURENTO_SERVLET_CONTEXT_LISTENER_ATTRIBUTE_NAME = KurentoApplicationContextUtils.class + "AttributeName"; // Is there any better mechanisms for enabling direct recovery of beans // (e.g. configurations) private static AnnotationConfigApplicationContext kurentoApplicationContextInternalReference; private static ConcurrentHashMap<String, AnnotationConfigApplicationContext> childContexts; private KurentoApplicationContextUtils() { } /** * This class returns the Spring KurentoApplicationContext, which is the * parent context for all specific Kurento Servlet contexts. In case a * pre-exiting Spring root WebApplicationContext if found, the returned * KurentoApplicationContext will be made child of this root context. When * necessary, this method creates the KurentoApplicationContext, so it * should never return null. * * This method MUST NOT be called in ServletContextListeners, given that at * that stage there might not be information about the presence of a root * Spring root WebApplicationConext. * * @param ctx * @return * */ public static AnnotationConfigApplicationContext createKurentoApplicationContext(ServletContext ctx) { Assert.notNull(ctx, "Cannot recover KurentoApplicationContext from a null ServletContext"); Assert.isNull(kurentoApplicationContextInternalReference, "Pre-existing Kurento ApplicationContext found. Cannot create a new instance."); kurentoApplicationContextInternalReference = new AnnotationConfigApplicationContext(); // Add or remove packages when required kurentoApplicationContextInternalReference.scan("com.kurento.kmf"); // Recover root WebApplicationContext context just in case // application developer is using Spring WebApplicationContext rootContext = WebApplicationContextUtils.getWebApplicationContext(ctx); if (rootContext != null) { kurentoApplicationContextInternalReference.setParent(rootContext); } final String jbossServerConfigDir = System.getProperty("jboss.server.config.dir"); final String kurentoPropertiesDir = System.getProperty("kurento.properties.dir"); final String kurentoProperties = "/kurento.properties"; InputStream inputStream = null; try { if (jbossServerConfigDir != null && new File(jbossServerConfigDir + kurentoProperties).exists()) { // First, look for JVM argument "jboss.server.config.dir" inputStream = new FileInputStream(jbossServerConfigDir + kurentoProperties); log.info("Found custom properties in 'jboss.server.config.dir': " + jbossServerConfigDir); } else if (kurentoPropertiesDir != null && new File(kurentoPropertiesDir + kurentoProperties).exists()) { // Second, look for JVM argument "kurento.properties.dir" log.info("Found custom properties in 'kurento.properties.dir': " + kurentoPropertiesDir); inputStream = new FileInputStream(kurentoPropertiesDir + kurentoProperties); } else { // Third, look for properties in Servlet Context ServletContextResource servletContextResource = new ServletContextResource(ctx, "/WEB-INF" + kurentoProperties); if (servletContextResource.exists()) { log.info("Found custom properties in Servlet Context: /WEB-INF" + kurentoProperties); inputStream = servletContextResource.getInputStream(); } } if (inputStream != null) { Properties properties = new Properties(); properties.load(inputStream); PropertyOverrideConfigurer propertyOverrideConfigurer = new PropertyOverrideConfigurer(); propertyOverrideConfigurer.setProperties(properties); kurentoApplicationContextInternalReference.addBeanFactoryPostProcessor(propertyOverrideConfigurer); inputStream.close(); } } catch (IOException e) { log.error("Exception loading custom properties", e); throw new RuntimeException(e); } kurentoApplicationContextInternalReference.refresh(); return kurentoApplicationContextInternalReference; } public static boolean kurentoApplicationContextExists() { return kurentoApplicationContextInternalReference != null; } public static AnnotationConfigApplicationContext getKurentoApplicationContext() { return kurentoApplicationContextInternalReference; } /** * Returns a specific application context associated to a Kurento handler * servlet. This method returns null if the context does not exist. * * @param servletClass * @param ctx * @return */ public static AnnotationConfigApplicationContext getKurentoServletApplicationContext(Class<?> servletClass, String servletName) { Assert.notNull(servletClass, "Cannot recover KurentoServletApplicationContext from a null Servlet class"); if (childContexts == null) { return null; } AnnotationConfigApplicationContext childAppContext = childContexts .get(servletClass.getName() + ":" + servletName); if (childAppContext == null) { return null; } return childAppContext; } public static AnnotationConfigApplicationContext createKurentoHandlerServletApplicationContext( Class<?> servletClass, String servletName, ServletContext sc, String handlerClassName) { Assert.notNull(sc, "Cannot create Kurento ServletApplicationContext from null ServletContext"); Assert.notNull(servletClass, "Cannot create KurentoServletApplicationContext from a null Servlet class"); Assert.notNull(servletClass, "Cannot create KurentoServletApplicationContext from a null Hanlder class"); if (childContexts == null) { childContexts = new ConcurrentHashMap<String, AnnotationConfigApplicationContext>(); } AnnotationConfigApplicationContext childContext = childContexts .get(servletClass.getName() + ":" + servletName); Assert.isNull(childContext, "Pre-existing context found associated to servlet class " + servletClass.getName() + " and servlet name " + servletName); childContext = new AnnotationConfigApplicationContext(); GenericBeanDefinition beanDefinition = new GenericBeanDefinition(); beanDefinition.setBeanClassName(handlerClassName); childContext.registerBeanDefinition(handlerClassName, beanDefinition); if (!kurentoApplicationContextExists()) { createKurentoApplicationContext(sc); } childContext.setParent(getKurentoApplicationContext()); childContext.refresh(); childContexts.put(servletClass.getName(), childContext); return childContext; } public static void closeAllKurentoApplicationContexts(ServletContext ctx) { Assert.notNull(ctx, "Cannot close contexts from a null ServletContext"); if (childContexts != null) { for (AnnotationConfigApplicationContext childContext : childContexts.values()) { log.info("Closing Kurento Servlet Application Context " + childContext); childContext.close(); } } childContexts = null; if (kurentoApplicationContextInternalReference != null) { log.info("Closing Kurento Application Context " + kurentoApplicationContextInternalReference); kurentoApplicationContextInternalReference.close(); } kurentoApplicationContextInternalReference = null; } public static void processInjectionBasedOnApplicationContext(Object bean, AnnotationConfigApplicationContext appContext) { Assert.notNull(appContext, "Cannot process bean injection. Reason the specified ApplicationContext is null"); Assert.notNull(bean, "Cannot process bean injection into null bean reference"); AutowiredAnnotationBeanPostProcessor bpp = new AutowiredAnnotationBeanPostProcessor(); bpp.setBeanFactory(appContext.getAutowireCapableBeanFactory()); bpp.processInjection(bean); } public static void processInjectionBasedOnKurentoApplicationContext(Object bean) { Assert.notNull(kurentoApplicationContextInternalReference, "Cannot process bean injection. Reason Kurento ApplicationContext has not been initialized"); Assert.notNull(bean, "Cannot process bean injection into null bean reference"); AutowiredAnnotationBeanPostProcessor bpp = new AutowiredAnnotationBeanPostProcessor(); bpp.setBeanFactory(kurentoApplicationContextInternalReference.getAutowireCapableBeanFactory()); bpp.processInjection(bean); } public static <T> T getConfiguration(Class<T> configurationClass) { Assert.notNull(kurentoApplicationContextInternalReference, "Cannot access configuration before creating Kurento Application Context"); T result = kurentoApplicationContextInternalReference.getBean(configurationClass); Assert.notNull(result, "No configuration has been found associated to type " + configurationClass.getName()); return result; } public static Object getBean(String name, Object... args) { Assert.notNull(kurentoApplicationContextInternalReference, "Cannot get bean for the following reason: Kurento ApplicationContext has not been initlized."); return kurentoApplicationContextInternalReference.getBean(name, args); } public static Object getBean(String name) { Assert.notNull(kurentoApplicationContextInternalReference, "Cannot get bean for the following reason: Kurento ApplicationContext has not been initlized."); return kurentoApplicationContextInternalReference.getBean(name); } public static void registerKurentoServletContextListener(ServletContext ctx) { // Add listener for closing Kurento ApplicationContexts on container // shutdown if (ctx.getAttribute(KURENTO_SERVLET_CONTEXT_LISTENER_ATTRIBUTE_NAME) != null) { log.info("Kurento ServletContextListener already registered, we don't register it again ..."); return; } log.info("Registering Kurento ServletContextListener ..."); ctx.setAttribute(KURENTO_SERVLET_CONTEXT_LISTENER_ATTRIBUTE_NAME, "initialized"); ctx.addListener(KurentoServletContextListener.class); } public static AnnotationConfigApplicationContext debugOnlyCreateKurentoApplicationContext() { Assert.isNull(kurentoApplicationContextInternalReference, "Pre-existing Kurento ApplicationContext found. Cannot create a new instance."); kurentoApplicationContextInternalReference = new AnnotationConfigApplicationContext(); // Add or remove packages when required kurentoApplicationContextInternalReference.scan("com.kurento.kmf"); kurentoApplicationContextInternalReference.refresh(); return kurentoApplicationContextInternalReference; } }