Java tutorial
/* * Copyright 2002-2006 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.richclient.application; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.springframework.beans.BeansException; import org.springframework.beans.factory.config.BeanDefinition; import org.springframework.beans.factory.config.BeanFactoryPostProcessor; import org.springframework.beans.factory.config.BeanPostProcessor; import org.springframework.beans.factory.config.ConfigurableBeanFactory; import org.springframework.beans.factory.config.ConfigurableListableBeanFactory; import org.springframework.context.MessageSource; import org.springframework.richclient.progress.ProgressMonitor; import org.springframework.util.Assert; /** * A {@code BeanFactoryPostProcessor} that notifies a specified * {@link ProgressMonitor} of progress made while loading a bean factory. * * <p> * The messages sent to the progress monitor can be internationalized by * providing a {@link MessageSource} to the constructor of this class. Note that * if a {@link MessageSource} is provided it must already be initialized in * order for it to successfully retrieve messages. * </p> * * <p> * The progress monitor will be notified once prior to initializing the beans in * the bean factory and once for each singleton bean before it is initialized. * The message keys used to find these messages are * {@value #LOADING_APP_CONTEXT_KEY} and {@value #LOADING_BEAN_KEY}. If the * message source is unable to find any messages under these keys, or if no * message source is provided, default messages (in English) will be used * instead. * </p> * * @author Kevin Stembridge * @since 0.3.0 * * @see ProgressMonitor * */ public class ProgressMonitoringBeanFactoryPostProcessor implements BeanFactoryPostProcessor { /** * The message key used to retrieve the message to be sent to the progress * monitor when the application context begins loading. */ public static final String LOADING_APP_CONTEXT_KEY = "progress.loading.applicationContext"; /** * The message key used to retrieve the message to be sent to the progress * monitor for each bean that is loaded. */ public static final String LOADING_BEAN_KEY = "progress.loading.bean"; private static final Log logger = LogFactory.getLog(ProgressMonitoringBeanFactoryPostProcessor.class); private final ProgressMonitor progressMonitor; private final MessageSource messageSource; private final String loadingAppContextMessage; /** * Creates a new {@code ProgressMonitoringBeanFactoryPostProcessor} that * will report the progress of loading the beans in a bean factory to the * given progress monitor, optionally providing internationalized messages. * * @param progressMonitor The progress monitor that will be notified of * progress while processing the bean factory. * @param messageSource The message source that will be used to resolve * messages to be displayed by the progress monitor. May be null. * * @throws IllegalArgumentException if {@code progressMonitor} is null. */ public ProgressMonitoringBeanFactoryPostProcessor(ProgressMonitor progressMonitor, MessageSource messageSource) { Assert.notNull(progressMonitor, "The ProgressMonitor cannot be null"); this.progressMonitor = progressMonitor; this.messageSource = messageSource; this.loadingAppContextMessage = getLoadingAppContextMessage(); } /** * Notifies this instance's associated progress monitor of progress made * while processing the given bean factory. * * @param beanFactory the bean factory that is to be processed. */ public void postProcessBeanFactory(final ConfigurableListableBeanFactory beanFactory) throws BeansException { if (beanFactory == null) { return; } String[] beanNames = beanFactory.getBeanDefinitionNames(); int singletonBeanCount = 0; for (int i = 0; i < beanNames.length; i++) { // using beanDefinition to check singleton property because when // accessing through // context (applicationContext.isSingleton(beanName)), bean will be // created already, // possibly bypassing other BeanFactoryPostProcessors BeanDefinition beanDefinition = beanFactory.getBeanDefinition(beanNames[i]); if (beanDefinition.isSingleton()) { singletonBeanCount++; } } this.progressMonitor.taskStarted(this.loadingAppContextMessage, singletonBeanCount); beanFactory.addBeanPostProcessor(new ProgressMonitoringBeanPostProcessor(beanFactory)); } private String getLoadingAppContextMessage() { String defaultMessage = "Loading Application Context ..."; if (this.messageSource == null) { return defaultMessage; } return this.messageSource.getMessage(LOADING_APP_CONTEXT_KEY, null, defaultMessage, null); } private class ProgressMonitoringBeanPostProcessor implements BeanPostProcessor { private final ConfigurableBeanFactory beanFactory; private ProgressMonitoringBeanPostProcessor(ConfigurableBeanFactory beanFactory) { Assert.notNull(beanFactory, "The bean factory cannot be null"); this.beanFactory = beanFactory; } /** * A default implementation that performs no operation on the bean. */ public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException { return bean; } /** * {@inheritDoc} */ public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException { if (logger.isTraceEnabled()) { logger.trace("BEGIN: postProcessBeforeInitialization(" + beanName + ")"); } if (this.beanFactory.containsLocalBean(beanName)) { String loadingBeanMessage = getLoadingBeanMessage(beanName); progressMonitor.subTaskStarted(loadingBeanMessage); progressMonitor.worked(1); } logger.trace("END: postProcessBeforeInitialization()"); return bean; } private String getLoadingBeanMessage(String beanName) { String defaultMessage = "Loading " + beanName + " ..."; if (messageSource == null) { return defaultMessage; } Object[] args = { beanName }; return messageSource.getMessage(LOADING_BEAN_KEY, args, defaultMessage, null); } } }