/*
* Copyright 2005-2007 Noelios Consulting.
*
* The contents of this file are subject to the terms of the Common Development
* and Distribution License (the "License"). You may not use this file except in
* compliance with the License.
*
* You can obtain a copy of the license at
* http://www.opensource.org/licenses/cddl1.txt See the License for the specific
* language governing permissions and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each file and
* include the License file at http://www.opensource.org/licenses/cddl1.txt If
* applicable, add the following below this CDDL HEADER, with the fields
* enclosed by brackets "[]" replaced with your own identifying information:
* Portions Copyright [yyyy] [name of copyright owner]
*/
package com.noelios.restlet.ext.servlet;
import java.io.IOException;
import java.util.List;
import java.lang.reflect.InvocationTargetException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.restlet.Application;
import org.restlet.Component;
import org.restlet.Context;
import org.restlet.Server;
import org.restlet.data.Protocol;
import com.noelios.restlet.http.HttpServerHelper;
/**
* Servlet acting like an HTTP server connector.
* See <a href="/documentation/1.0/faq#02">Developper FAQ
* #2</a> for details on how to integrate a Restlet application into a servlet
* container.<br/> Here is a sample configuration for your Restlet webapp:
*
* <pre>
* <?xml version="1.0" encoding="ISO-8859-1"?>
* <!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN" "http://java.sun.com/dtd/web-app_2_3.dtd">
* <web-app>
* <display-name>Restlet adapter</display-name>
*
* <!-- Your application class name -->
* <context-param>
* <param-name>org.restlet.application</param-name>
* <param-value>com.noelios.restlet.test.TraceApplication</param-value>
* </context-param>
*
* <!-- Restlet adapter -->
* <servlet>
* <servlet-name>ServerServlet</servlet-name>
* <servlet-class>com.noelios.restlet.ext.servlet.ServerServlet</servlet-class>
* </servlet>
*
* <!-- Catch all requests -->
* <servlet-mapping>
* <servlet-name>ServerServlet</servlet-name>
* <url-pattern>/*</url-pattern>
* </servlet-mapping>
* </web-app>
* </pre>
*
* The enumeration of initParameters of your Servlet will be copied to the
* "context.parameters" property of your application. This way, you can pass
* additional initialization parameters to your Restlet application, and share
* them with existing Servlets.
*
* @see <a href="http://java.sun.com/j2ee/">J2EE home page</a>
* @author Jerome Louvel (contact@noelios.com)
*/
public class ServerServlet extends HttpServlet {
/**
* The Servlet context initialization parameter's name containing the name
* of the Servlet context attribute that should be used to store the Restlet
* Application instance.
*/
private static final String NAME_APPLICATION_ATTRIBUTE = "org.restlet.attribute.application";
/** The default value for the NAME_APPLICATION_ATTRIBUTE parameter. */
private static final String NAME_APPLICATION_ATTRIBUTE_DEFAULT = "com.noelios.restlet.ext.servlet.ServerServlet.application";
/**
* The Servlet context initialization parameter's name containing the name
* of the Servlet context attribute that should be used to store the Restlet
* Component instance.
*/
private static final String NAME_COMPONENT_ATTRIBUTE = "org.restlet.attribute.component";
/** The default value for the NAME_COMPONENT_ATTRIBUTE parameter. */
private static final String NAME_COMPONENT_ATTRIBUTE_DEFAULT = "com.noelios.restlet.ext.servlet.ServerServlet.component";
/**
* The Servlet context initialization parameter's name containing the name
* of the Servlet context attribute that should be used to store the HTTP
* server connector instance.
*/
private static final String NAME_SERVER_ATTRIBUTE = "org.restlet.attribute.server";
/** The default value for the NAME_SERVER_ATTRIBUTE parameter. */
private static final String NAME_SERVER_ATTRIBUTE_DEFAULT = "com.noelios.restlet.ext.servlet.ServerServlet.server";
/** Serial version identifier. */
private static final long serialVersionUID = 1L;
/** The associated Restlet application. */
private transient Application application;
/** The associated Restlet component. */
private transient Component component;
/** The associated HTTP server helper. */
private transient HttpServerHelper helper;
/**
* Constructor.
*/
public ServerServlet() {
this.application = null;
this.component = null;
this.helper = null;
}
/**
* Creates the single Application used by this Servlet.
*
* @param context
* The Context for the Application
*
* @return The newly created Application or null if unable to create
*/
public Application createApplication(Context context) {
Application application = null;
// Try to instantiate a new target application
// First, find the application class name
String applicationClassName = getInitParameter(Application.KEY, null);
// Load the application class using the given class name
if (applicationClassName != null) {
try {
// According to
// http://www.caucho.com/resin-3.0/webapp/faq.xtp#Class.forName()-doesn't-seem-to-work-right
// this approach may need to used when loading classes.
Class<?> targetClass;
ClassLoader loader = Thread.currentThread()
.getContextClassLoader();
if (loader != null)
targetClass = Class.forName(applicationClassName, false,
loader);
else
targetClass = Class.forName(applicationClassName);
try {
// Create a new instance of the application class by
// invoking the constructor with the Context parameter.
application = (Application) targetClass.getConstructor(
Context.class).newInstance(context);
} catch (NoSuchMethodException e) {
log(
"[Noelios Restlet Engine] - The ServerServlet couldn't invoke the constructor of the target class. Please check this class has a constructor with a single parameter of Context. The empty constructor and the context setter wille used instead. "
+ applicationClassName, e);
// The constructor with the Context parameter does not
// exist. Instantiate an application with the default
// constructor then invoke the setContext method.
application = (Application) targetClass.getConstructor()
.newInstance();
}
} catch (ClassNotFoundException e) {
log(
"[Noelios Restlet Engine] - The ServerServlet couldn't find the target class. Please check that your classpath includes "
+ applicationClassName, e);
} catch (InstantiationException e) {
log(
"[Noelios Restlet Engine] - The ServerServlet couldn't instantiate the target class. Please check this class has an empty constructor "
+ applicationClassName, e);
} catch (IllegalAccessException e) {
log(
"[Noelios Restlet Engine] - The ServerServlet couldn't instantiate the target class. Please check that you have to proper access rights to "
+ applicationClassName, e);
} catch (NoSuchMethodException e) {
log(
"[Noelios Restlet Engine] - The ServerServlet couldn't invoke the constructor of the target class. Please check this class has a constructor with a single parameter of Context "
+ applicationClassName, e);
} catch (InvocationTargetException e) {
log(
"[Noelios Restlet Engine] - The ServerServlet couldn't instantiate the target class. An exception was thrown while creating "
+ applicationClassName, e);
}
if (application != null) {
// Set the context based on the Servlet's context
application.setContext(new ServletContextAdapter(this,
application, context));
}
}
return application;
}
/**
* Creates the associated HTTP server handling calls.
*
* @param request
* The HTTP Servlet request.
* @return The new HTTP server handling calls.
*/
public HttpServerHelper createServer(HttpServletRequest request) {
HttpServerHelper result = null;
Component component = getComponent();
Application application = getApplication();
if ((component != null) && (application != null)) {
// First, let's locate the closest component
Server server = new Server(component.getContext(),
(List<Protocol>) null, request.getLocalAddr(), request
.getLocalPort(), component);
result = new HttpServerHelper(server);
// Attach the application
String uriPattern = request.getContextPath()
+ request.getServletPath();
component.getDefaultHost().attach(uriPattern, application);
}
return result;
}
@Override
public void destroy() {
if ((getApplication() != null) && (getApplication().isStarted())) {
try {
getApplication().stop();
} catch (Exception e) {
log("Error during the stopping of the Restlet Application", e);
}
}
super.destroy();
}
/**
* Returns the application. It creates a new one if none exists.
*
* @return The application.
*/
public Application getApplication() {
Application result = this.application;
if (result == null) {
synchronized (ServerServlet.class) {
// Find the attribute name to use to store the application
String applicationAttributeName = getInitParameter(
NAME_APPLICATION_ATTRIBUTE,
NAME_APPLICATION_ATTRIBUTE_DEFAULT);
// Look up the attribute for a target
result = (Application) getServletContext().getAttribute(
applicationAttributeName);
if (result == null) {
result = createApplication(getComponent().getContext());
getServletContext().setAttribute(applicationAttributeName,
result);
}
this.application = result;
}
}
return result;
}
/**
* Returns the component. It creates a new one if none exists.
*
* @return The component.
*/
public Component getComponent() {
Component result = this.component;
if (result == null) {
synchronized (ServerServlet.class) {
// Find the attribute name to use to store the component
String componentAttributeName = getInitParameter(
NAME_COMPONENT_ATTRIBUTE,
NAME_COMPONENT_ATTRIBUTE_DEFAULT);
// Look up the attribute for a target
result = (Component) getServletContext().getAttribute(
componentAttributeName);
if (result == null) {
result = new Component();
getServletContext().setAttribute(componentAttributeName,
result);
}
this.component = result;
}
}
return result;
}
/**
* Returns the value of a given initialization parameter, first from the
* Servlet configuration, then from the Web Application context.
*
* @param name
* The parameter name.
* @param defaultValue
* The default to use in case the parameter is not found.
* @return The value of the parameter or null.
*/
public String getInitParameter(String name, String defaultValue) {
String result = getServletConfig().getInitParameter(name);
if (result == null) {
result = getServletConfig().getServletContext().getInitParameter(
name);
}
if (result == null) {
result = defaultValue;
}
return result;
}
/**
* Returns the associated HTTP server handling calls. It creates a new one
* if none exists.
*
* @param request
* The HTTP Servlet request.
* @return The HTTP server handling calls.
*/
public HttpServerHelper getServer(HttpServletRequest request) {
HttpServerHelper result = this.helper;
if (result == null) {
synchronized (ServerServlet.class) {
// Find the attribute name to use to store the server reference
String serverAttributeName = getInitParameter(
NAME_SERVER_ATTRIBUTE, NAME_SERVER_ATTRIBUTE_DEFAULT);
// Look up the attribute for a target
result = (HttpServerHelper) getServletContext().getAttribute(
serverAttributeName);
if (result == null) {
result = createServer(request);
getServletContext().setAttribute(serverAttributeName,
result);
}
this.helper = result;
}
}
return result;
}
@Override
public void init() throws ServletException {
if ((getApplication() != null) && (getApplication().isStopped())) {
try {
getApplication().start();
} catch (Exception e) {
log("Error during the starting of the Restlet Application", e);
}
}
}
/**
* Services a HTTP Servlet request as an uniform call.
*
* @param request
* The HTTP Servlet request.
* @param response
* The HTTP Servlet response.
*/
public void service(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
HttpServerHelper helper = getServer(request);
if (helper != null) {
helper
.handle(new ServletCall(helper.getServer(), request,
response));
} else {
log("[Noelios Restlet Engine] - Unable to get the Restlet HTTP server connector. Status code 500 returned.");
response.sendError(500);
}
}
}