| /* |
| * Copyright 2009 Google Inc. |
| * |
| * 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 com.google.gwt.jsonp.server; |
| |
| import java.io.IOException; |
| |
| import javax.servlet.http.HttpServlet; |
| import javax.servlet.http.HttpServletRequest; |
| import javax.servlet.http.HttpServletResponse; |
| |
| /** |
| * A servlet that returns a given value, following the JSONP protocol. |
| * Expected url parameters: |
| * |
| * <ul> |
| * <li>action: one of the following values: |
| * <ul> |
| * <li>TIMEOUT: don't respond anything to simulate a timeout |
| * <li>SUCCESS: return a JSON value |
| * <li>FAILURE: return an error |
| * </ul> |
| * <li>value: the JSON value to return if action == "SUCCESS" |
| * <li>error: the error message to return if action == "FAILURE" |
| * </ul> |
| */ |
| public class EchoServlet extends HttpServlet { |
| |
| private enum Action { |
| SUCCESS, |
| FAILURE, |
| TIMEOUT |
| } |
| |
| @Override |
| protected void service(HttpServletRequest req, HttpServletResponse res) |
| throws IOException { |
| res.setContentType("application/javascript"); |
| switch (Action.valueOf(req.getParameter("action"))) { |
| case SUCCESS: { |
| handleDelay(req); |
| String callback = req.getParameter("callback"); |
| String value = req.getParameter("value"); |
| if (value == null) { |
| value = ""; |
| } |
| res.getWriter().println(callback + "(" + value + ");"); |
| res.getWriter().flush(); |
| break; |
| } |
| |
| case FAILURE: { |
| handleDelay(req); |
| String failureCallback = req.getParameter("failureCallback"); |
| String error = req.getParameter("error"); |
| if (failureCallback != null) { |
| res.getWriter().println(failureCallback + "('" + error + "');"); |
| res.getWriter().flush(); |
| } else { |
| // If no failure callback is defined, send the error through the |
| // success callback. |
| String callback = req.getParameter("callback"); |
| res.getWriter().println(callback + "('" + error + "');"); |
| res.getWriter().flush(); |
| } |
| break; |
| } |
| |
| case TIMEOUT: |
| // Don't respond anything so that a timeout happens. |
| } |
| } |
| |
| /** |
| * Handle a delay query parameter if present. |
| * |
| * @param req |
| */ |
| private void handleDelay(HttpServletRequest req) { |
| String delayVal = req.getParameter("delay"); |
| if (delayVal != null) { |
| int delayMs = Integer.parseInt(delayVal); |
| try { |
| Thread.sleep(delayMs); |
| } catch (InterruptedException e) { |
| log("Interrupted sleep, continuing"); |
| } |
| } |
| } |
| } |