Java tutorial
/* * $Id: ClassReloadingXMLWebApplicationContext.java 1292705 2012-02-23 08:40:53Z lukaszlenart $ * * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF 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.apache.struts2.spring; import com.opensymphony.xwork2.util.classloader.FileResourceStore; import com.opensymphony.xwork2.util.classloader.JarResourceStore; import com.opensymphony.xwork2.util.classloader.ReloadingClassLoader; import com.opensymphony.xwork2.util.logging.Logger; import com.opensymphony.xwork2.util.logging.LoggerFactory; import org.apache.commons.jci.monitor.FilesystemAlterationListener; import org.apache.commons.jci.monitor.FilesystemAlterationMonitor; import org.apache.commons.jci.monitor.FilesystemAlterationObserver; import org.apache.commons.lang3.StringUtils; import org.apache.struts2.dispatcher.Dispatcher; import org.springframework.web.context.support.XmlWebApplicationContext; import org.springframework.beans.factory.support.DefaultListableBeanFactory; import org.springframework.beans.factory.config.ConfigurableListableBeanFactory; import org.springframework.beans.BeansException; import javax.servlet.ServletContext; import java.io.File; import java.util.List; import java.util.ArrayList; import java.util.Set; import java.util.HashSet; import java.util.regex.Pattern; /** * This class can be used instead of XmlWebApplicationContext, and it will watch jar files and directories for changes * and reload then changed classes. * <br /> * To use this class: * <ul> * <li>Set "struts.devMode" to "true" </li> * <li>Set "struts.class.reloading.watchList" to a comma separated list of directories, or jar files (absolute paths)</p> * <li>Add this to web.xml: * <pre> * <context-param> * <param-name>contextClass</param-name> * <param-value>org.apache.struts2.spring.ClassReloadingXMLWebApplicationContext</param-value> * </context-param> * </li> * <li>Add Apache Commons JCI FAM to the classpath. If you are using maven, add this to pom.xml: * <pre> * <dependency> * <groupId>org.apache.commons</groupId> * <artifactId>commons-jci-fam</artifactId> * <version>1.0</version> * <optional>true</optional> * </dependency> * </pre> * </li> * </ul> */ public class ClassReloadingXMLWebApplicationContext extends XmlWebApplicationContext implements FilesystemAlterationListener { private static final Logger LOG = LoggerFactory.getLogger(ClassReloadingXMLWebApplicationContext.class); protected ReloadingClassLoader classLoader; protected FilesystemAlterationMonitor fam; protected ClassReloadingBeanFactory beanFactory; //reload the runtime configuration when a change is detected private boolean reloadConfig; public void setupReloading(String[] watchList, String acceptClasses, ServletContext servletContext, boolean reloadConfig) { this.reloadConfig = reloadConfig; classLoader = new ReloadingClassLoader(ClassReloadingXMLWebApplicationContext.class.getClassLoader()); //make a list of accepted classes if (StringUtils.isNotBlank(acceptClasses)) { String[] splitted = acceptClasses.split(","); Set<Pattern> patterns = new HashSet<Pattern>(splitted.length); for (String pattern : splitted) patterns.add(Pattern.compile(pattern)); classLoader.setAccepClasses(patterns); } fam = new FilesystemAlterationMonitor(); //setup stores for (String watch : watchList) { File file = new File(watch); //make it absolute, if it is a relative path if (!file.isAbsolute()) file = new File(servletContext.getRealPath(watch)); if (watch.endsWith(".jar")) { classLoader.addResourceStore(new JarResourceStore(file)); //register with the fam fam.addListener(file, this); if (LOG.isDebugEnabled()) { LOG.debug("Watching [#0] for changes", file.getAbsolutePath()); } } else { //get all subdirs List<File> dirs = new ArrayList<File>(); getAllPaths(file, dirs); classLoader.addResourceStore(new FileResourceStore(file)); for (File dir : dirs) { //register with the fam fam.addListener(dir, this); if (LOG.isDebugEnabled()) { LOG.debug("Watching [#0] for changes", dir.getAbsolutePath()); } } } } //setup the bean factory beanFactory = new ClassReloadingBeanFactory(); beanFactory.setInstantiationStrategy(new ClassReloadingInstantiationStrategy()); beanFactory.setBeanClassLoader(classLoader); //start watch thread fam.start(); } /** * If root is a dir, find al the subdir paths */ private void getAllPaths(File root, List<File> dirs) { dirs.add(root); if (root.isDirectory()) { File[] files = root.listFiles(); if (files != null) { for (File file : files) { if (file.isDirectory()) { getAllPaths(file, dirs); } } } } } public void close() { super.close(); if (fam != null) { fam.removeListener(this); fam.stop(); } } public void refresh() throws BeansException, IllegalStateException { if (classLoader != null) { classLoader.reload(); } super.refresh(); } protected DefaultListableBeanFactory createBeanFactory() { return beanFactory != null ? beanFactory : super.createBeanFactory(); } protected void prepareBeanFactory(ConfigurableListableBeanFactory beanFactory) { super.prepareBeanFactory(beanFactory); //overwrite the class loader in the bean factory if (classLoader != null) beanFactory.setBeanClassLoader(classLoader); } public void onDirectoryChange(File file) { reload(file); } public void onDirectoryCreate(File file) { reload(file); } public void onDirectoryDelete(File file) { } public void onFileChange(File file) { reload(file); } public void onFileCreate(File file) { reload(file); } private void reload(File file) { if (classLoader != null) { final boolean debugEnabled = LOG.isDebugEnabled(); if (debugEnabled) LOG.debug("Change detected in file [#0], reloading class loader", file.getAbsolutePath()); classLoader.reload(); if (reloadConfig && Dispatcher.getInstance() != null) { if (debugEnabled) LOG.debug("Change detected in file [#0], reloading configuration", file.getAbsolutePath()); Dispatcher.getInstance().getConfigurationManager().reload(); } } } public void onFileDelete(File file) { } public void onStart(FilesystemAlterationObserver filesystemAlterationObserver) { } public void onStop(FilesystemAlterationObserver filesystemAlterationObserver) { } public ReloadingClassLoader getReloadingClassLoader() { return classLoader; } }