/*
* Copyright 2007-2010 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.impalaframework.web.spring.servlet;
import java.io.IOException;
import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.impalaframework.facade.ModuleManagementFacade;
import org.impalaframework.module.spi.FrameworkLockHolder;
import org.impalaframework.web.servlet.invoker.HttpServiceInvoker;
import org.impalaframework.web.servlet.invoker.ServletInvokerUtils;
import org.impalaframework.web.spring.ImpalaFrameworkServlet;
import org.impalaframework.web.spring.helper.ImpalaServletUtils;
import org.springframework.beans.BeansException;
import org.springframework.web.context.WebApplicationContext;
import org.springframework.web.servlet.DispatcherServlet;
import org.springframework.web.util.NestedServletException;
/**
* Abstract base servlet for extending Spring MVC capabilities with Impala.
* Wraps <code>doService</code> with a read-write lock so that application context refresh is
* properly synchronized
* @author Phil Zoio
*/
public abstract class BaseExternalModuleServlet extends DispatcherServlet implements HttpServiceInvoker, ImpalaFrameworkServlet {
private static final long serialVersionUID = 1L;
private HttpServiceInvoker invoker;
/**
* Sets whether to set the thread context class loader to that of the class loader
* of the module. By default this is false.
*/
private boolean setThreadContextClassLoader;
public BaseExternalModuleServlet() {
super();
}
protected abstract WebApplicationContext createWebApplicationContext() throws BeansException;
@Override
protected void doService(HttpServletRequest request, HttpServletResponse response) throws Exception {
invoker.invoke(request, response, null);
}
public void invoke(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain)
throws IOException, ServletException {
try {
super.doService(request, response);
} catch (Exception e) {
throw new NestedServletException("Request processing failed", e);
}
}
@Override
protected WebApplicationContext initWebApplicationContext() throws BeansException {
ModuleManagementFacade moduleManagementFacade = ImpalaServletUtils.getModuleManagementFacade(getServletContext());
FrameworkLockHolder frameworkLockHolder = moduleManagementFacade.getFrameworkLockHolder();
try {
frameworkLockHolder.writeLock();
WebApplicationContext wac = createWebApplicationContext();
HttpServlet delegateServlet = this;
this.invoker = getInvoker(wac, delegateServlet, frameworkLockHolder, this.setThreadContextClassLoader);
//FIXME this probably shouldn't automatically be being called. How to stop it from being called inappropriately
//However, it must be called
onRefresh(wac);
ImpalaServletUtils.publishWebApplicationContext(wac, this);
return wac;
}
finally {
frameworkLockHolder.writeUnlock();
}
}
protected HttpServiceInvoker getInvoker(WebApplicationContext wac,
HttpServlet delegateServlet,
FrameworkLockHolder frameworkLockHolder,
boolean setThreadContextClassLoader) {
return ServletInvokerUtils.getHttpServiceInvoker(delegateServlet, wac, frameworkLockHolder, setThreadContextClassLoader);
}
@Override
public void destroy() {
ImpalaServletUtils.unpublishWebApplicationContext(this);
super.destroy();
}
/* ************************ Package methods ********************** */
HttpServiceInvoker getInvoker() {
return invoker;
}
/* ************************ Injection setters ********************** */
public void setSetThreadContextClassLoader(boolean setThreadContextClassLoader) {
this.setThreadContextClassLoader = setThreadContextClassLoader;
}
}