Re: [xSocket-develop] basic question about read data from readByteBufferByDelimiter

[Gregor R. <gre...@go...>]

… you do two things in our onData() implementation: Echoing the received
data and printing it.

If you are using the async flush mode, the buffer will be written to the
network asynchronously by the internal I/O thread. This means by returning
from the write method the buffer will be accessed by the I/O thread in the
background in a concurrent way. Because you access the buffer after the
write call to print it race conditions occurs. The solution is to duplicate
the byte buffer by calling <ByteBuffer>.duplicate() method or not to set the
flush mode to async.

Converting byte buffers to a string is a little bit tricky. You can use the
convenience method DataConverter.toString(<ByteBuffer[]>, encoding) to
convert the byte buffers to a string.

Gregor



2008/10/29 beijing welcome <wel...@gm...>

> hi, xSocket develop folks,
>
> This might be a very basic question, I want to read a file by stream and
> send to server, then do something, however, ByteBuffer[] in
> readByteBufferByDelimiter is empty in server side.
>
> paste the code below.
>
> Thank you in advance!
>
> =============== MServer.java ==============
> package mserver;
>
> import java.io.Closeable;
> import java.io.IOException;
> import java.net.InetAddress;
> import java.util.HashSet;
> import java.util.Set;
>
> import org.xsocket.connection.IConnectHandler;
> import org.xsocket.connection.IHandler;
> import org.xsocket.connection.INonBlockingConnection;
> import org.xsocket.connection.IServer;
> import org.xsocket.connection.Server;
> import org.xsocket.connection.ConnectionUtils;
> import org.xsocket.connection.IConnection.FlushMode;
>
> import mserver.MServerHandler;
>
>
> public class MServer implements Closeable {
>
>     private IServer server = null;
>
>     public MServer(int listenPort) throws Exception {
>
>         IHandler hdl = new MServerHandler();
>
>         server = new Server(listenPort, hdl);
>         server.setFlushMode(FlushMode.ASYNC);  // performance improvement
>
>         ConnectionUtils.start(server);
>         ConnectionUtils.registerMBean(server);
>     }
>
>     public static void main(String... args) throws Exception {
>         int port = 8888;
>         new MServer(port);
>     }
>
>     public InetAddress getLocalAddress() {
>         return server.getLocalAddress();
>     }
>
>     public void close() throws IOException {
>         if (server != null) {
>             server.close();
>         }
>     }
>
> }
> ==============================================
>
> =================== MServerHandler.java ===========================
>
> package mserver;
>
> import java.io.IOException;
> import java.nio.BufferUnderflowException;
> import java.nio.ByteBuffer;
> import java.nio.CharBuffer;
> import java.nio.charset.Charset;
> import java.nio.charset.CharsetDecoder;
>
> import org.xsocket.Execution;
> import org.xsocket.MaxReadSizeExceededException;
> import org.xsocket.connection.IConnectHandler;
> import org.xsocket.connection.IDataHandler;
> import org.xsocket.connection.INonBlockingConnection;
> import org.xsocket.connection.IConnection.FlushMode;
>
> @Execution(Execution.NONTHREADED)
> public class MServerHandler implements IConnectHandler, IDataHandler {
>     public static final String DELIMITER = "\r\n";
>     static Charset charset = Charset.forName("gb2312");
>     static CharsetDecoder decoder = charset.newDecoder();
>     static CharBuffer charBuffer = null ;
>
>     public boolean onConnect(INonBlockingConnection connection) throws
> IOException, BufferUnderflowException, MaxReadSizeExceededException {
>         connection.setFlushmode(FlushMode.ASYNC);
>         connection.setAutoflush(false);
> //        connection.write("Welcome to MServer!");
>         System.out.println(connection.getRemoteAddress() + " connected!");
>         return true;
>     }
>
>     public boolean onData(INonBlockingConnection connection) throws
> IOException, BufferUnderflowException {
>         ByteBuffer[] buffer =
> connection.readByteBufferByDelimiter(DELIMITER, Integer.MAX_VALUE);
> //        connection.write("Server: ");
>
>         connection.write(buffer);
>         connection.write(DELIMITER);
>         for (int j = 0; j < buffer.length; ++j) {
>             buffer[j].flip();
>             charBuffer = decoder.decode(buffer[j]);
> //          System.out.println( " charBuffer= "   +  charBuffer);
>        // this line is empty!
>           System.out.println(charBuffer.toString());
>             System.out.println(j);
>         }
>         connection.flush();
>         System.out.println("====");
>         return true;
>     }
> }
>
>
> =========================================
> ================= MServerClient.java ========================
> package mserver;
>
> import java.io.InputStreamReader;
> import java.io.LineNumberReader;
> import java.net.Socket;
>
> public class MServerClient {
>     public void startClient() throws Exception {
>         int port = 8888;
>         Socket client = new Socket("localhost", port);
>         // next step is send a file here.
>         client.getOutputStream().write("test\r\n".getBytes());
>         LineNumberReader lnr = new LineNumberReader(
>                 new InputStreamReader(client.getInputStream()));
>         String response = lnr.readLine();
>         System.out.println(response);
>         lnr.close();
>         client.close();
>
>     }
>     /**
>      * @param args
>      */
>     public static void main(String[] args) {
>         // TODO Auto-generated method stub
>         MServerClient client = new MServerClient();
>         try {
>             client.startClient();
>         } catch (Exception e) {
>             e.printStackTrace();
>         }
>     }
>
> }
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