servletcontextawareprocessor.java

来自「一个关于Spring框架的示例应用程序,简单使用,可以参考.」· Java 代码 · 共 73 行

/*
 * Copyright 2002-2004 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.web.context.support;

import javax.servlet.ServletContext;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanPostProcessor;
import org.springframework.web.context.ServletContextAware;

/**
 * BeanPostProcessor implementation that passes the ServletContext to
 * beans that implement the ApplicationContextAware or ResourceLoaderAware
 * interfaces. If both are implemented, the latter is satisfied first.
 *
 * <p>Web application contexts will automatically register this with their
 * underlying bean factory. Applications do not use this directly.
 *
 * @author Juergen Hoeller
 * @since 12.03.2004
 * @see org.springframework.web.context.ServletContextAware
 * @see org.springframework.web.context.support.XmlWebApplicationContext#postProcessBeanFactory
 */
public class ServletContextAwareProcessor implements BeanPostProcessor {

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

	private final ServletContext servletContext;

	/**
	 * Create a new ServletContextAwareProcessor for the given context.
	 */
	public ServletContextAwareProcessor(ServletContext servletContext) {
		this.servletContext = servletContext;
	}

	public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
		if (bean instanceof ServletContextAware) {
			if (this.servletContext == null) {
				throw new IllegalStateException("Cannot satisfy ServletContextAware for bean '" +
						beanName + "' because there is no ServletContext");
			}
			if (logger.isDebugEnabled()) {
				logger.debug("Invoking setServletContext on ServletContextAware bean '" + beanName + "'");
			}
			((ServletContextAware) bean).setServletContext(this.servletContext);
		}
		return bean;
	}

	public Object postProcessAfterInitialization(Object bean, String beanName) {
		return bean;
	}

}