springwebapplicationfactory.java

Wicket一个开发Java Web应用程序框架。它使得开发web应用程序变得容易而轻松。 Wicket利用一个POJO data beans组件使得它可以与任何持久层技术相结合。

/*
 * 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.wicket.spring;

import java.util.Map;

import javax.servlet.ServletContext;

import org.apache.wicket.protocol.http.IWebApplicationFactory;
import org.apache.wicket.protocol.http.WebApplication;
import org.apache.wicket.protocol.http.WicketFilter;
import org.springframework.beans.factory.BeanFactoryUtils;
import org.springframework.context.ApplicationContext;
import org.springframework.web.context.support.WebApplicationContextUtils;


/**
 * Implementation of IWebApplicationFactory that pulls the WebApplication object out of spring
 * application context.
 * 
 * Configuration example:
 * 
 * <pre>
 *    &lt;servlet&gt;
 *    &lt;servlet-name&gt;phonebook&lt;/servlet-name&gt;
 *    &lt;servlet-class&gt;org.apache.wicket.protocol.http.WicketServlet&lt;/servlet-class&gt;
 *    &lt;init-param&gt;
 *    &lt;param-name&gt;applicationFactoryClassName&lt;/param-name&gt;
 *    &lt;param-value&gt;org.apache.wicket.spring.SpringWebApplicationFactory&lt;/param-value&gt;
 *    &lt;/init-param&gt;
 *    &lt;load-on-startup&gt;1&lt;/load-on-startup&gt;
 *    &lt;/servlet&gt;
 * </pre>
 * 
 * beanName init parameter can be used if there are multiple WebApplications defined on the spring
 * application context.
 * 
 * Example:
 * 
 * <pre>
 *    &lt;servlet&gt;
 *    &lt;servlet-name&gt;phonebook&lt;/servlet-name&gt;
 *    &lt;servlet-class&gt;org.apache.wicket.protocol.http.WicketServlet&lt;/servlet-class&gt;
 *    &lt;init-param&gt;
 *    &lt;param-name&gt;applicationFactoryClassName&lt;/param-name&gt;
 *    &lt;param-value&gt;org.apache.wicket.spring.SpringWebApplicationFactory&lt;/param-value&gt;
 *    &lt;/init-param&gt;
 *    &lt;init-param&gt;
 *    &lt;param-name&gt;beanName&lt;/param-name&gt;
 *    &lt;param-value&gt;phonebookApplication&lt;/param-value&gt;
 *    &lt;/init-param&gt;
 *    &lt;load-on-startup&gt;1&lt;/load-on-startup&gt;
 *    &lt;/servlet&gt;
 * </pre>
 * 
 * 
 * @author Igor Vaynberg (ivaynberg)
 * @author Janne Hietam&auml;ki (jannehietamaki)
 * 
 */
public class SpringWebApplicationFactory implements IWebApplicationFactory
{
	/**
	 * @see IWebApplicationFactory#createApplication(WicketFilter)
	 */
	public WebApplication createApplication(WicketFilter filter)
	{
		ServletContext sc = filter.getFilterConfig().getServletContext();
		ApplicationContext ac = WebApplicationContextUtils.getRequiredWebApplicationContext(sc);

		String beanName = filter.getFilterConfig().getInitParameter("applicationBean");
		return createApplication(ac, beanName);
	}

	private WebApplication createApplication(ApplicationContext ac, String beanName)
	{
		if (beanName != null)
		{
			WebApplication application = (WebApplication)ac.getBean(beanName);
			if (application == null)
			{
				throw new IllegalArgumentException(
						"Unable to find WebApplication bean with name [" + beanName + "]");
			}
			return application;
		}
		else
		{
			Map beans = BeanFactoryUtils.beansOfTypeIncludingAncestors(ac, WebApplication.class,
					false, false);
			if (beans.size() == 0)
			{
				throw new IllegalStateException("bean of type [" + WebApplication.class.getName() +
						"] not found");
			}
			if (beans.size() > 1)
			{
				throw new IllegalStateException("more then one bean of type [" +
						WebApplication.class.getName() + "] found, must have only one");
			}
			return (WebApplication)beans.values().iterator().next();
		}
	}
}