/trunk/src/main/java/flowersinthesand/example/ChatServlet.java
Java | 201 lines | 153 code | 37 blank | 11 comment | 7 complexity | 33b820ba8ad117a0b39022fa929405db MD5 | raw file
- package flowersinthesand.example;
-
- import java.io.IOException;
- import java.io.PrintWriter;
- import java.util.LinkedHashMap;
- import java.util.Map;
- import java.util.Queue;
- import java.util.UUID;
- import java.util.concurrent.BlockingQueue;
- import java.util.concurrent.ConcurrentHashMap;
- import java.util.concurrent.ConcurrentLinkedQueue;
- import java.util.concurrent.LinkedBlockingQueue;
-
- import javax.servlet.AsyncContext;
- import javax.servlet.AsyncEvent;
- import javax.servlet.AsyncListener;
- import javax.servlet.ServletConfig;
- import javax.servlet.ServletException;
- import javax.servlet.annotation.WebServlet;
- import javax.servlet.http.HttpServletRequest;
- import javax.servlet.http.HttpServletResponse;
-
- import org.eclipse.jetty.util.UrlEncoded;
- import org.eclipse.jetty.websocket.WebSocket;
- import org.eclipse.jetty.websocket.WebSocketServlet;
-
- import com.google.gson.Gson;
-
- @WebServlet(urlPatterns = "/example/chat", asyncSupported = true)
- public class ChatServlet extends WebSocketServlet {
-
- private static final long serialVersionUID = -8823775068689773674L;
-
- /* Common */
- private BlockingQueue<String> messages = new LinkedBlockingQueue<String>();
- private Thread notifier = new Thread(new Runnable() {
- public void run() {
- boolean done = false;
- while (!done) {
- try {
- String message = messages.take();
- for (AsyncContext asyncContext : asyncContexts.values()) {
- try {
- // Message
- PrintWriter writer = asyncContext.getResponse().getWriter();
- writer.print(message.length());
- writer.print(";");
- writer.print(message);
- writer.print(";");
- writer.flush();
- } catch (Exception e) {
- asyncContexts.values().remove(asyncContext);
- }
- }
- for (ChatWebSocket webSocket : webSockets) {
- try {
- webSocket.connection.sendMessage(message);
- } catch (Exception e) {
- webSockets.remove(webSocket);
- }
- }
- } catch (InterruptedException e) {
- done = true;
- }
- }
- }
- });
-
- @Override
- public void init(ServletConfig config) throws ServletException {
- super.init(config);
- notifier.start();
- }
-
- @Override
- public void destroy() {
- messages.clear();
- webSockets.clear();
- asyncContexts.clear();
- notifier.interrupt();
- }
-
- /* HTTP Streaming powered by Servlet 3.0 */
- private Map<String, AsyncContext> asyncContexts = new ConcurrentHashMap<String, AsyncContext>();
-
- // GET method is used to open stream
- @Override
- protected void doGet(HttpServletRequest request, HttpServletResponse response)
- throws ServletException, IOException {
- response.setCharacterEncoding("utf-8");
-
- // Content-Type header
- response.setContentType("text/plain");
-
- // Access-Control-Allow-Origin header
- response.setHeader("Access-Control-Allow-Origin", "*");
-
- PrintWriter writer = response.getWriter();
-
- // Id
- final String id = UUID.randomUUID().toString();
- writer.print(id);
- writer.print(';');
-
- // Padding
- for (int i = 0; i < 1024; i++) {
- writer.print(' ');
- }
- writer.print(';');
- writer.flush();
-
- final AsyncContext ac = request.startAsync();
- ac.setTimeout(5 * 60 * 1000);
- ac.addListener(new AsyncListener() {
- public void onComplete(AsyncEvent event) throws IOException {
- asyncContexts.remove(id);
- }
-
- public void onTimeout(AsyncEvent event) throws IOException {
- asyncContexts.remove(id);
- }
-
- public void onError(AsyncEvent event) throws IOException {
- asyncContexts.remove(id);
- }
-
- public void onStartAsync(AsyncEvent event) throws IOException {
-
- }
- });
- asyncContexts.put(id, ac);
- }
-
- // POST method is used to handle data sent by user through the stream
- @Override
- protected void doPost(HttpServletRequest request, HttpServletResponse response)
- throws ServletException, IOException {
- request.setCharacterEncoding("utf-8");
-
- if ("close".equals(request.getParameter("metadata.type"))) {
- AsyncContext ac = asyncContexts.get(request.getParameter("metadata.id"));
- if (ac != null) {
- ac.complete();
- }
-
- return;
- }
-
- // Handles data sent from a client
- Map<String, String> data = new LinkedHashMap<String, String>();
- data.put("username", request.getParameter("username"));
- data.put("message", request.getParameter("message"));
-
- try {
- messages.put(new Gson().toJson(data));
- } catch (InterruptedException e) {
- throw new IOException(e);
- }
- }
-
- /* WebSocket powered by Jetty */
- private Queue<ChatWebSocket> webSockets = new ConcurrentLinkedQueue<ChatWebSocket>();
-
- @Override
- public WebSocket doWebSocketConnect(HttpServletRequest request, String protocol) {
- return new ChatWebSocket();
- }
-
- class ChatWebSocket implements WebSocket.OnTextMessage {
-
- Connection connection;
-
- @Override
- public void onOpen(Connection connection) {
- this.connection = connection;
- webSockets.add(this);
- }
-
- @Override
- public void onClose(int closeCode, String message) {
- webSockets.remove(this);
- }
-
- @Override
- public void onMessage(String queryString) {
- UrlEncoded parameters = new UrlEncoded(queryString);
-
- Map<String, String> data = new LinkedHashMap<String, String>();
- data.put("username", parameters.getString("username"));
- data.put("message", parameters.getString("message"));
-
- try {
- messages.put(new Gson().toJson(data));
- } catch (InterruptedException e) {
- throw new RuntimeException(e);
- }
- }
-
- }
-
- }