org.ws13.vaadin.osgi.dm.app.SpringApplicationServlet.java Source code

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Here is the source code for org.ws13.vaadin.osgi.dm.app.SpringApplicationServlet.java

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/*******************************************************************************
 * Copyright 2011 ctranxuan
 * 
 * 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.ws13.vaadin.osgi.dm.app;

import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;

import org.springframework.web.context.WebApplicationContext;
import org.springframework.web.context.support.WebApplicationContextUtils;

import com.vaadin.Application;
import com.vaadin.terminal.gwt.server.AbstractApplicationServlet;

@SuppressWarnings("serial")
public class SpringApplicationServlet extends AbstractApplicationServlet {

    /** Default application bean name in Spring application context. */
    private static final String DEFAULT_APP_BEAN_NAME = "application";

    /** Application bean name in Spring application context. */
    private String name;

    /**
     * Get and stores in the servlet the application bean's name in the Spring's
     * context. It's expected to be configured as a the servlet
     * <code>init-param</code> named applicationBeanName. If no
     * param is found, the default is "application".
     * 
     * @see AbstractApplicationServlet#init(ServletConfig)
     */
    @Override
    public void init(ServletConfig config) throws ServletException {

        super.init(config);

        String name = config.getInitParameter("applicationBeanName");

        this.name = name == null ? DEFAULT_APP_BEAN_NAME : name;
    }

    /**
     * Get the application bean in Spring's context.
     * 
     * @see AbstractApplicationServlet#getNewApplication(HttpServletRequest)
     */
    @Override
    protected Application getNewApplication(HttpServletRequest request) throws ServletException {

        WebApplicationContext wac = WebApplicationContextUtils.getWebApplicationContext(getServletContext());

        if (wac == null) {
            throw new ServletException("Cannot get an handle on Spring's context. Is Spring running?"
                    + "Check there's an org.springframework.web.context.ContextLoaderListener configured.");
        }

        String[] beanDefinitionNames = wac.getBeanDefinitionNames();
        for (String string : beanDefinitionNames) {
            System.out.println("SpringApplicationServlet.getNewApplication() ->" + string);
        }

        Application bean = wac.getBean(name, Application.class);

        if (!(bean instanceof Application)) {

            throw new ServletException("Bean " + name + " is not of expected class Application");
        }

        return bean;
    }

    /**
     * Get the application class from the bean configured in Spring's context.
     * 
     * @see AbstractApplicationServlet#getApplicationClass()
     */
    @Override
    protected Class<? extends Application> getApplicationClass() throws ClassNotFoundException {

        WebApplicationContext wac = WebApplicationContextUtils.getWebApplicationContext(getServletContext());

        if (wac == null) {
            throw new ClassNotFoundException("Cannot get an handle on Spring's context. Is Spring running? "
                    + "Check there's an org.springframework.web.context.ContextLoaderListener configured.");
        }
        String[] beanDefinitionNames = wac.getBeanDefinitionNames();
        for (String string : beanDefinitionNames) {
            System.out.println("SpringApplicationServlet.getApplicationClass() " + string);
        }

        Application bean = wac.getBean(name, Application.class);

        if (bean == null) {

            throw new ClassNotFoundException("No application bean found under name " + name);
        }

        return bean.getClass();
    }
}