Jetty WTP Plugin/Jetty WTP Websocket Wizard

Using the Jetty Websocket Wizard

The plugin, org.eclipse.jst.server.jetty.ui.websocket, provides a wizard that you can use to create a Jetty WebSocket.

This document provides examples for the following tasks:

• Creating an implementataion of the org.eclipse.jetty.websocket.WebSocketServlet, which uses an implementation of org.eclipse.jetty.websocket.WebSocket
• Modifying the web.xml to declare the WebSocketServlet createdt-name + servlet-mapping). ??
• TODO : create an HTML page that calls the WebSocketServlet.

To create a WebSocketServlet, complete the following steps.

1. In the Eclipse menu, navigate to File->New>-Other .
The Select a wizard dialog box opens.






2. Select Web/Jetty WebSocket .
The Create Jetty-WebSocket dialog box opens.

.







3. In the Java package field, enter org.sample.websocket .
4. In the Class name field, enter ChatWebSocketServlet .
The Superclass field is automatically filled as org.eclipse.jetty.websocket.WebSocketServlet.
5. Click Next .
The Create Jetty-WebSocket Deployment Descriptor dialog box opens.







This is the same dialog box that the Servlet uses.

6. Here you can define the servlet-mappings.
7. Click Next .
The Create Jetty-WebSocket Modifiers, Interfaces and Methods dialog box opens.







8. Here you can generate some methods. The wizard generates doPost for WebSocket using ???
9. Click Finish .
Your workspace looks like this :







The wizard generates :

• a class ChatWebSocketServlet :

package org.sample.websocket;
 
import java.io.IOException;
import java.util.Set;
import java.util.concurrent.CopyOnWriteArraySet;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.eclipse.jetty.websocket.WebSocket;
import org.eclipse.jetty.websocket.WebSocketServlet;
 
/**
 * Jetty WebSocketServlet implementation class ChatWebSocketServlet
 */
                      public
                      class
                      ChatWebSocketServlet
                      extends
                      WebSocketServlet
                      {
                      private
                      static
                      final
                      long
                      serialVersionUID
                      =
                      1L
                      ;
                      /**
     * @see WebSocketServlet#WebSocketServlet()
     */
                      public
                      ChatWebSocketServlet
                      (
                      )
                      {
                      super
                      (
                      )
                      ;
                      // TODO Auto-generated constructor stub
                      }
                      private
                      final
                      Set
                      <
                      ChatWebSocket
                      >
                      members
                      =
                      new
                      CopyOnWriteArraySet
                      <
                      ChatWebSocket
                      >
                      (
                      )
                      ;
                      /**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
                      protected
                      void
                      doGet
                      (
                      HttpServletRequest request, HttpServletResponse response
                      )
                      throws
                      ServletException,
                      IOException
                      {
                      // TODO Auto-generated method stub
                      }
                      /**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
                      protected
                      void
                      doPost
                      (
                      HttpServletRequest request, HttpServletResponse response
                      )
                      throws
                      ServletException,
                      IOException
                      {
                      getServletContext
                      (
                      )
                      .
                      getNamedDispatcher
                      (
                      "default"
                      )
                      .
                      forward
                      (
                      request, response
                      )
                      ;
                      }
                      /*
	 * @see org.eclipse.jetty.websocket.WebSocketServlet#doWebSocketConnect(javax.servlet.http.HttpServletRequest, java.lang.String)
	 */
                      protected
                      WebSocket doWebSocketConnect
                      (
                      HttpServletRequest request,
                      String
                      protocol
                      )
                      {
                      return
                      new
                      ChatWebSocket
                      (
                      )
                      ;
                      }
                      class
                      ChatWebSocket
                      implements
                      WebSocket
                      {
                      private
                      Outbound outbound
                      ;
                      public
                      void
                      onConnect
                      (
                      Outbound outbound
                      )
                      {
                      this
                      .
                      outbound
                      =
                      outbound
                      ;
                      members.
                      add
                      (
                      this
                      )
                      ;
                      }
                      /*
		 * @see org.eclipse.jetty.websocket.WebSocket#onMessage(byte, byte[],
		 * int, int)
		 */
                      public
                      void
                      onMessage
                      (
                      byte
                      frame,
                      byte
                      [
                      ]
                      data,
                      int
                      offset,
                      int
                      length
                      )
                      {
                      }
                      /*
		 * @see org.eclipse.jetty.websocket.WebSocket#onMessage(byte,
		 * java.lang.String)
		 */
                      public
                      void
                      onMessage
                      (
                      byte
                      frame,
                      String
                      data
                      )
                      {
                      for
                      (
                      ChatWebSocket member
                      :
                      members
                      )
                      {
                      try
                      {
                      member.
                      outbound
                      .
                      sendMessage
                      (
                      frame, data
                      )
                      ;
                      }
                      catch
                      (
                      IOException
                      e
                      )
                      {
                      // org.eclipse.jetty.util.log.Log.warn(e);
                      e.
                      printStackTrace
                      (
                      )
                      ;
                      }
                      }
                      }
                      /*
		 * @see org.eclipse.jetty.websocket.WebSocket#onDisconnect()
		 */
		public void onDisconnect() {
			members.remove(this);
		}
	}
 
 
}

1.web.xml is modified like this :

  <servlet>
    <description></description>
    <display-name>ChatWebSocketServlet</display-name>
    <servlet-name>ChatWebSocketServlet</servlet-name>
    <servlet-class>org.sample.websocket.ChatWebSocketServlet</servletclass>
  </servlet>
  <servlet-mapping>
    <servlet-name>ChatWebSocketServlet</servlet-name>
    <url-pattern>/ChatWebSocketServlet</url-pattern>
  </servlet-mapping>

2.TODO : generate an HTML file which consume the WebSocket.