Example usage for java.nio.channels SelectionKey OP_READ

List of usage examples for java.nio.channels SelectionKey OP_READ

Introduction

In this page you can find the example usage for java.nio.channels SelectionKey OP_READ.

Prototype

int OP_READ

To view the source code for java.nio.channels SelectionKey OP_READ.

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Document

Operation-set bit for read operations.

Usage

From source file:MainClass.java

public static void main(String[] args) throws IOException {
    Charset charset = Charset.forName("ISO-8859-1");
    CharsetEncoder encoder = charset.newEncoder();
    CharsetDecoder decoder = charset.newDecoder();

    ByteBuffer buffer = ByteBuffer.allocate(512);

    Selector selector = Selector.open();

    ServerSocketChannel server = ServerSocketChannel.open();
    server.socket().bind(new java.net.InetSocketAddress(8000));
    server.configureBlocking(false);/*from w  ww .  j  ava  2  s  .  co  m*/
    SelectionKey serverkey = server.register(selector, SelectionKey.OP_ACCEPT);

    for (;;) {
        selector.select();
        Set keys = selector.selectedKeys();

        for (Iterator i = keys.iterator(); i.hasNext();) {
            SelectionKey key = (SelectionKey) i.next();
            i.remove();

            if (key == serverkey) {
                if (key.isAcceptable()) {
                    SocketChannel client = server.accept();
                    client.configureBlocking(false);
                    SelectionKey clientkey = client.register(selector, SelectionKey.OP_READ);
                    clientkey.attach(new Integer(0));
                }
            } else {
                SocketChannel client = (SocketChannel) key.channel();
                if (!key.isReadable())
                    continue;
                int bytesread = client.read(buffer);
                if (bytesread == -1) {
                    key.cancel();
                    client.close();
                    continue;
                }
                buffer.flip();
                String request = decoder.decode(buffer).toString();
                buffer.clear();
                if (request.trim().equals("quit")) {
                    client.write(encoder.encode(CharBuffer.wrap("Bye.")));
                    key.cancel();
                    client.close();
                } else {
                    int num = ((Integer) key.attachment()).intValue();
                    String response = num + ": " + request.toUpperCase();
                    client.write(encoder.encode(CharBuffer.wrap(response)));
                    key.attach(new Integer(num + 1));
                }
            }
        }
    }
}

From source file:GetWebPageApp.java

public static void main(String args[]) throws Exception {
    String resource, host, file;//  w  w w  .  j  av  a2  s .  c  om
    int slashPos;

    resource = "www.java2s.com/index.htm"; // skip HTTP://
    slashPos = resource.indexOf('/'); // find host/file separator
    if (slashPos < 0) {
        resource = resource + "/";
        slashPos = resource.indexOf('/');
    }
    file = resource.substring(slashPos); // isolate host and file parts
    host = resource.substring(0, slashPos);
    System.out.println("Host to contact: '" + host + "'");
    System.out.println("File to fetch : '" + file + "'");

    SocketChannel channel = null;

    try {
        Charset charset = Charset.forName("ISO-8859-1");
        CharsetDecoder decoder = charset.newDecoder();
        CharsetEncoder encoder = charset.newEncoder();

        ByteBuffer buffer = ByteBuffer.allocateDirect(1024);
        CharBuffer charBuffer = CharBuffer.allocate(1024);

        InetSocketAddress socketAddress = new InetSocketAddress(host, 80);
        channel = SocketChannel.open();
        channel.configureBlocking(false);
        channel.connect(socketAddress);

        selector = Selector.open();

        channel.register(selector, SelectionKey.OP_CONNECT | SelectionKey.OP_READ);

        while (selector.select(500) > 0) {
            Set readyKeys = selector.selectedKeys();
            try {
                Iterator readyItor = readyKeys.iterator();

                while (readyItor.hasNext()) {

                    SelectionKey key = (SelectionKey) readyItor.next();
                    readyItor.remove();
                    SocketChannel keyChannel = (SocketChannel) key.channel();

                    if (key.isConnectable()) {
                        if (keyChannel.isConnectionPending()) {
                            keyChannel.finishConnect();
                        }
                        String request = "GET " + file + " \r\n\r\n";
                        keyChannel.write(encoder.encode(CharBuffer.wrap(request)));
                    } else if (key.isReadable()) {
                        keyChannel.read(buffer);
                        buffer.flip();

                        decoder.decode(buffer, charBuffer, false);
                        charBuffer.flip();
                        System.out.print(charBuffer);

                        buffer.clear();
                        charBuffer.clear();

                    } else {
                        System.err.println("Unknown key");
                    }
                }
            } catch (ConcurrentModificationException e) {
            }
        }
    } catch (UnknownHostException e) {
        System.err.println(e);
    } catch (IOException e) {
        System.err.println(e);
    } finally {
        if (channel != null) {
            try {
                channel.close();
            } catch (IOException ignored) {
            }
        }
    }
    System.out.println("\nDone.");
}

From source file:Main.java

public static void main(String[] args) throws Exception {
    InetAddress serverIPAddress = InetAddress.getByName("localhost");
    int port = 19000;
    InetSocketAddress serverAddress = new InetSocketAddress(serverIPAddress, port);
    Selector selector = Selector.open();
    SocketChannel channel = SocketChannel.open();
    channel.configureBlocking(false);/*  w  w  w  .j  ava2s .c o  m*/
    channel.connect(serverAddress);
    int operations = SelectionKey.OP_CONNECT | SelectionKey.OP_READ | SelectionKey.OP_WRITE;
    channel.register(selector, operations);

    userInputReader = new BufferedReader(new InputStreamReader(System.in));
    while (true) {
        if (selector.select() > 0) {
            boolean doneStatus = processReadySet(selector.selectedKeys());
            if (doneStatus) {
                break;
            }
        }
    }
    channel.close();
}

From source file:DaytimeServer.java

public static void main(String args[]) {
    try { // Handle startup exceptions at the end of this block
        // Get an encoder for converting strings to bytes
        CharsetEncoder encoder = Charset.forName("US-ASCII").newEncoder();

        // Allow an alternative port for testing with non-root accounts
        int port = 13; // RFC867 specifies this port.
        if (args.length > 0)
            port = Integer.parseInt(args[0]);

        // The port we'll listen on
        SocketAddress localport = new InetSocketAddress(port);

        // Create and bind a tcp channel to listen for connections on.
        ServerSocketChannel tcpserver = ServerSocketChannel.open();
        tcpserver.socket().bind(localport);

        // Also create and bind a DatagramChannel to listen on.
        DatagramChannel udpserver = DatagramChannel.open();
        udpserver.socket().bind(localport);

        // Specify non-blocking mode for both channels, since our
        // Selector object will be doing the blocking for us.
        tcpserver.configureBlocking(false);
        udpserver.configureBlocking(false);

        // The Selector object is what allows us to block while waiting
        // for activity on either of the two channels.
        Selector selector = Selector.open();

        // Register the channels with the selector, and specify what
        // conditions (a connection ready to accept, a datagram ready
        // to read) we'd like the Selector to wake up for.
        // These methods return SelectionKey objects, which we don't
        // need to retain in this example.
        tcpserver.register(selector, SelectionKey.OP_ACCEPT);
        udpserver.register(selector, SelectionKey.OP_READ);

        // This is an empty byte buffer to receive emtpy datagrams with.
        // If a datagram overflows the receive buffer size, the extra bytes
        // are automatically discarded, so we don't have to worry about
        // buffer overflow attacks here.
        ByteBuffer receiveBuffer = ByteBuffer.allocate(0);

        // Now loop forever, processing client connections
        for (;;) {
            try { // Handle per-connection problems below
                // Wait for a client to connect
                selector.select();//w  ww  .  j  av a  2s  . c  o m

                // If we get here, a client has probably connected, so
                // put our response into a ByteBuffer.
                String date = new java.util.Date().toString() + "\r\n";
                ByteBuffer response = encoder.encode(CharBuffer.wrap(date));

                // Get the SelectionKey objects for the channels that have
                // activity on them. These are the keys returned by the
                // register() methods above. They are returned in a
                // java.util.Set.
                Set keys = selector.selectedKeys();

                // Iterate through the Set of keys.
                for (Iterator i = keys.iterator(); i.hasNext();) {
                    // Get a key from the set, and remove it from the set
                    SelectionKey key = (SelectionKey) i.next();
                    i.remove();

                    // Get the channel associated with the key
                    Channel c = (Channel) key.channel();

                    // Now test the key and the channel to find out
                    // whether something happend on the TCP or UDP channel
                    if (key.isAcceptable() && c == tcpserver) {
                        // A client has attempted to connect via TCP.
                        // Accept the connection now.
                        SocketChannel client = tcpserver.accept();
                        // If we accepted the connection successfully,
                        // the send our respone back to the client.
                        if (client != null) {
                            client.write(response); // send respone
                            client.close(); // close connection
                        }
                    } else if (key.isReadable() && c == udpserver) {
                        // A UDP datagram is waiting. Receive it now,
                        // noting the address it was sent from.
                        SocketAddress clientAddress = udpserver.receive(receiveBuffer);
                        // If we got the datagram successfully, send
                        // the date and time in a response packet.
                        if (clientAddress != null)
                            udpserver.send(response, clientAddress);
                    }
                }
            } catch (java.io.IOException e) {
                // This is a (hopefully transient) problem with a single
                // connection: we log the error, but continue running.
                // We use our classname for the logger so that a sysadmin
                // can configure logging for this server independently
                // of other programs.
                Logger l = Logger.getLogger(DaytimeServer.class.getName());
                l.log(Level.WARNING, "IOException in DaytimeServer", e);
            } catch (Throwable t) {
                // If anything else goes wrong (out of memory, for example)
                // then log the problem and exit.
                Logger l = Logger.getLogger(DaytimeServer.class.getName());
                l.log(Level.SEVERE, "FATAL error in DaytimeServer", t);
                System.exit(1);
            }
        }
    } catch (Exception e) {
        // This is a startup error: there is no need to log it;
        // just print a message and exit
        System.err.println(e);
        System.exit(1);
    }
}

From source file:PrintServiceWebInterface.java

public static void main(String[] args) throws IOException {
    // Get the character encoders and decoders we'll need
    Charset charset = Charset.forName("ISO-8859-1");
    CharsetEncoder encoder = charset.newEncoder();

    // The HTTP headers we send back to the client are fixed
    String headers = "HTTP/1.1 200 OK\r\n" + "Content-type: text/html\r\n" + "Connection: close\r\n" + "\r\n";

    // We'll use two buffers in our response. One holds the fixed
    // headers, and the other holds the variable body of the response.
    ByteBuffer[] buffers = new ByteBuffer[2];
    buffers[0] = encoder.encode(CharBuffer.wrap(headers));
    ByteBuffer body = ByteBuffer.allocateDirect(16 * 1024);
    buffers[1] = body;//  w w  w  . j a v  a 2 s. co m

    // Find all available PrintService objects to describe
    PrintService[] services = PrintServiceLookup.lookupPrintServices(null, null);

    // All of the channels we use in this code will be in non-blocking
    // mode. So we create a Selector object that will block while
    // monitoring all of the channels and will only stop blocking when
    // one or more of the channels is ready for I/O of some sort.
    Selector selector = Selector.open();

    // Create a new ServerSocketChannel, and bind it to port 8000.
    // Note that we have to do this using the underlying ServerSocket.
    ServerSocketChannel server = ServerSocketChannel.open();
    server.socket().bind(new java.net.InetSocketAddress(8000));

    // Put the ServerSocketChannel into non-blocking mode
    server.configureBlocking(false);

    // Now register the channel with the Selector. The SelectionKey
    // represents the registration of this channel with this Selector.
    SelectionKey serverkey = server.register(selector, SelectionKey.OP_ACCEPT);

    for (;;) { // The main server loop. The server runs forever.
        // This call blocks until there is activity on one of the
        // registered channels. This is the key method in non-blocking I/O.
        selector.select();

        // Get a java.util.Set containing the SelectionKey objects for
        // all channels that are ready for I/O.
        Set keys = selector.selectedKeys();

        // Use a java.util.Iterator to loop through the selected keys
        for (Iterator i = keys.iterator(); i.hasNext();) {
            // Get the next SelectionKey in the set, and then remove it
            // from the set. It must be removed explicitly, or it will
            // be returned again by the next call to select().
            SelectionKey key = (SelectionKey) i.next();
            i.remove();

            // Check whether this key is the SelectionKey we got when
            // we registered the ServerSocketChannel.
            if (key == serverkey) {
                // Activity on the ServerSocketChannel means a client
                // is trying to connect to the server.
                if (key.isAcceptable()) {
                    // Accept the client connection, and obtain a
                    // SocketChannel to communicate with the client.
                    SocketChannel client = server.accept();

                    // Make sure we actually got a connection
                    if (client == null)
                        continue;

                    // Put the client channel in non-blocking mode.
                    client.configureBlocking(false);

                    // Now register the client channel with the Selector,
                    // specifying that we'd like to know when there is
                    // data ready to read on the channel.
                    SelectionKey clientkey = client.register(selector, SelectionKey.OP_READ);
                }
            } else {
                // If the key we got from the Set of keys is not the
                // ServerSocketChannel key, then it must be a key
                // representing one of the client connections.
                // Get the channel from the key.
                SocketChannel client = (SocketChannel) key.channel();

                // If we got here, it should mean that there is data to
                // be read from the channel, but we double-check here.
                if (!key.isReadable())
                    continue;

                // Now read bytes from the client. We assume that
                // we get all the client's bytes in one read operation
                client.read(body);

                // The data we read should be some kind of HTTP GET
                // request. We don't bother checking it however since
                // there is only one page of data we know how to return.
                body.clear();

                // Build an HTML document as our reponse.
                // The body of the document contains PrintService details
                StringBuffer response = new StringBuffer();
                response.append(
                        "<html><head><title>Printer Status</title></head>" + "<body><h1>Printer Status</h1>");
                for (int s = 0; s < services.length; s++) {
                    PrintService service = services[s];
                    response.append("<h2>").append(service.getName()).append("</h2><table>");
                    Attribute[] attrs = service.getAttributes().toArray();
                    for (int a = 0; a < attrs.length; a++) {
                        Attribute attr = attrs[a];
                        response.append("<tr><td>").append(attr.getName()).append("</td><td>").append(attr)
                                .append("</tr>");
                    }
                    response.append("</table>");
                }
                response.append("</body></html>\r\n");

                // Encode the response into the body ByteBuffer
                encoder.reset();
                encoder.encode(CharBuffer.wrap(response), body, true);
                encoder.flush(body);

                body.flip(); // Prepare the body buffer to be drained
                // While there are bytes left to write
                while (body.hasRemaining()) {
                    // Write both header and body buffers
                    client.write(buffers);
                }
                buffers[0].flip(); // Prepare header buffer for next write
                body.clear(); // Prepare body buffer for next read

                // Once we've sent our response, we have no more interest
                // in the client channel or its SelectionKey
                client.close(); // Close the channel.
                key.cancel(); // Tell Selector to stop monitoring it.
            }
        }
    }
}

From source file:org.apache.axis2.transport.nhttp.LoggingIOSession.java

private static String formatOps(int ops) {
    StringBuffer buffer = new StringBuffer(6);
    buffer.append('[');
    if ((ops & SelectionKey.OP_READ) > 0) {
        buffer.append('r');
    }/*from ww w.  ja va 2 s . co  m*/
    if ((ops & SelectionKey.OP_WRITE) > 0) {
        buffer.append('w');
    }
    if ((ops & SelectionKey.OP_ACCEPT) > 0) {
        buffer.append('a');
    }
    if ((ops & SelectionKey.OP_CONNECT) > 0) {
        buffer.append('c');
    }
    buffer.append(']');
    return buffer.toString();
}

From source file:org.sipfoundry.sipxbridge.symmitron.DataShuffler.java

private static synchronized void initializeSelector() {

    try {/*from   w  ww .  java 2 s . co m*/
        if (selector != null) {
            selector.close();
        }
        selector = Selector.open();

        for (Bridge bridge : ConcurrentSet.getBridges()) {

            for (Sym session : bridge.sessions) {
                try {
                    if (session.getReceiver() != null && bridge.getState() == BridgeState.RUNNING
                            && session.getReceiver().getDatagramChannel().isOpen()) {

                        session.getReceiver().getDatagramChannel().configureBlocking(false);
                        session.getReceiver().getDatagramChannel().register(selector, SelectionKey.OP_READ);
                    }
                } catch (ClosedChannelException ex) {
                    // Avoid loading any closed channels in our select set.
                    continue;
                }
            }
            initializeSelectors.set(false);
        }

    } catch (IOException ex) {
        logger.error("Unepxected exception", ex);
        return;
    }

}

From source file:com.ok2c.lightmtp.impl.protocol.LoggingIOSession.java

private static String formatOps(final int ops) {
    final StringBuilder buffer = new StringBuilder(6);
    buffer.append('[');
    if ((ops & SelectionKey.OP_READ) > 0) {
        buffer.append('r');
    }//  w w w  . j  av a 2s. co m
    if ((ops & SelectionKey.OP_WRITE) > 0) {
        buffer.append('w');
    }
    if ((ops & SelectionKey.OP_ACCEPT) > 0) {
        buffer.append('a');
    }
    if ((ops & SelectionKey.OP_CONNECT) > 0) {
        buffer.append('c');
    }
    buffer.append(']');
    return buffer.toString();
}

From source file:org.pvalsecc.comm.ServerConnection.java

/**
 * Asynchronous. Just queue the data to be sent and tell the selector we want to send some data. When ready,
 * {@code send} will be called./*from ww  w.j a v  a  2  s . c o  m*/
 */
protected synchronized void answer(ByteBuffer buffer) {
    toSend.add(buffer);
    key.interestOps(SelectionKey.OP_READ | SelectionKey.OP_WRITE);
    key.selector().wakeup();
}

From source file:me.xingrz.prox.udp.UdpProxySession.java

public void send(ByteBuffer buffer) throws IOException {
    serverChannel.register(selector, SelectionKey.OP_READ, this);
    serverChannel.send(buffer, new InetSocketAddress(getRemoteAddress(), getRemotePort()));
}