/*
 * Copyright 2002-2017 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.ServletConfig;
import javax.servlet.ServletContext;

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

BeanPostProcessor implementation that passes the ServletContext to beans that implement the ServletContextAware interface. 
Web application contexts will automatically register this with their
underlying bean factory. Applications do not use this directly.
Author:
Juergen Hoeller, Phillip Webb
See Also:
ServletContextAware
AbstractRefreshableWebApplicationContext.postProcessBeanFactory
Since:
12.03.2004/**
 * {@link org.springframework.beans.factory.config.BeanPostProcessor}
 * implementation that passes the ServletContext to beans that implement
 * the {@link ServletContextAware} interface.
 *
 * <p>Web application contexts will automatically register this with their
 * underlying bean factory. Applications do not use this directly.
 *
 * @author Juergen Hoeller
 * @author Phillip Webb
 * @since 12.03.2004
 * @see org.springframework.web.context.ServletContextAware
 * @see org.springframework.web.context.support.XmlWebApplicationContext#postProcessBeanFactory
 */
public class ServletContextAwareProcessor implements BeanPostProcessor {

	@Nullable
	private ServletContext servletContext;

	@Nullable
	private ServletConfig servletConfig;


	
Create a new ServletContextAwareProcessor without an initial context or config. When this constructor is used the getServletContext() and/or getServletConfig() methods should be overridden. /**
	 * Create a new ServletContextAwareProcessor without an initial context or config.
	 * When this constructor is used the {@link #getServletContext()} and/or
	 * {@link #getServletConfig()} methods should be overridden.
	 */
	protected ServletContextAwareProcessor() {
	}

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

	
Create a new ServletContextAwareProcessor for the given config.
/**
	 * Create a new ServletContextAwareProcessor for the given config.
	 */
	public ServletContextAwareProcessor(ServletConfig servletConfig) {
		this(null, servletConfig);
	}

	
Create a new ServletContextAwareProcessor for the given context and config.
/**
	 * Create a new ServletContextAwareProcessor for the given context and config.
	 */
	public ServletContextAwareProcessor(@Nullable ServletContext servletContext, @Nullable ServletConfig servletConfig) {
		this.servletContext = servletContext;
		this.servletConfig = servletConfig;
	}


	
Returns the ServletContext to be injected or null. This method can be overridden by subclasses when a context is obtained after the post-processor has been registered. /**
	 * Returns the {@link ServletContext} to be injected or {@code null}. This method
	 * can be overridden by subclasses when a context is obtained after the post-processor
	 * has been registered.
	 */
	@Nullable
	protected ServletContext getServletContext() {
		if (this.servletContext == null && getServletConfig() != null) {
			return getServletConfig().getServletContext();
		}
		return this.servletContext;
	}

	
Returns the ServletConfig to be injected or null. This method can be overridden by subclasses when a context is obtained after the post-processor has been registered. /**
	 * Returns the {@link ServletConfig} to be injected or {@code null}. This method
	 * can be overridden by subclasses when a context is obtained after the post-processor
	 * has been registered.
	 */
	@Nullable
	protected ServletConfig getServletConfig() {
		return this.servletConfig;
	}

	@Override
	public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
		if (getServletContext() != null && bean instanceof ServletContextAware) {
			((ServletContextAware) bean).setServletContext(getServletContext());
		}
		if (getServletConfig() != null && bean instanceof ServletConfigAware) {
			((ServletConfigAware) bean).setServletConfig(getServletConfig());
		}
		return bean;
	}

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

}