package com.commons.sigae.server;
 
import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
 
import org.springframework.web.context.ServletContextAware;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.mvc.Controller;
 
import com.google.gwt.user.client.rpc.IncompatibleRemoteServiceException;
import com.google.gwt.user.client.rpc.RemoteService;
import com.google.gwt.user.client.rpc.SerializationException;
import com.google.gwt.user.server.rpc.RPC;
import com.google.gwt.user.server.rpc.RPCRequest;
import com.google.gwt.user.server.rpc.RemoteServiceServlet;
 
public class GWTController extends RemoteServiceServlet implements Controller, ServletContextAware {
 
    private ServletContext servletContext;
 
	public ServletContext getServletContext() {
        return servletContext;
    }
 
    public void setServletContext(ServletContext servletContext) {
        this.servletContext = servletContext;
    }
 
	// Instance fields
	private RemoteService remoteService;
	private Class remoteServiceClass;
 
	// Public methods
	/**
	 * Implements Spring Controller interface method.
	 * 
	 * Call GWT's RemoteService doPost() method and return null.
	 * 
	 * @param request
	 *            current HTTP request
	 * @param response
	 *            current HTTP response
	 * @return a ModelAndView to render, or null if handled directly
	 * @throws Exception
	 *             in case of errors
	 */
	public ModelAndView handleRequest(HttpServletRequest request,
			HttpServletResponse response) throws Exception {
		doPost(request, response);
		return null; // response handled by GWT RPC over XmlHttpRequest
	}
 
	/**
	 * Process the RPC request encoded into the payload string and return a
	 * string that encodes either the method return or an exception thrown by
	 * it.
	 */
	public String processCall(String payload) throws SerializationException {
		try {
			RPCRequest rpcRequest = RPC.decodeRequest(payload, this.remoteServiceClass);
 
			// delegate work to the spring injected service
			return RPC.invokeAndEncodeResponse(this.remoteService, rpcRequest.getMethod(), rpcRequest.getParameters());
		} catch (IncompatibleRemoteServiceException e) {
			return RPC.encodeResponseForFailure(null, e);
		}
	}
 
	/**
	 * Setter for Spring injection of the GWT RemoteService object.
	 * 
	 * @param RemoteService
	 *            the GWT RemoteService implementation that will be delegated to
	 *            by the {@code GWTController}.
	 */
	public void setRemoteService(RemoteService remoteService) {
		this.remoteService = remoteService;
		this.remoteServiceClass = this.remoteService.getClass();
	}
}