/* * Copyright (c) 1995 - 2008 Sun Microsystems, Inc.  All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * *   - Redistributions of source code must retain the above copyright *     notice, this list of conditions and the following disclaimer. * *   - Redistributions in binary form must reproduce the above copyright *     notice, this list of conditions and the following disclaimer in the *     documentation and/or other materials provided with the distribution. * *   - Neither the name of Sun Microsystems nor the names of its *     contributors may be used to endorse or promote products derived *     from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ /* * Java(TM) SE 6 version. * Exercise for the reader: Convert this applet to use SwingWorker * and Timer. SwingWorker can be downloaded at: * https://swingworker.dev.java.net/ * SwingWorker must be downloaded for JavaSE 5, but will be included * in JavaSE 6. */import javax.swing.*;import java.awt.*;import java.awt.event.*;import java.io.*;import java.net.*;import java.util.*;public class TalkClientApplet extends JApplet 				      implements Runnable,						 ActionListener {    private Socket socket;    private BufferedWriter os;    private BufferedReader is;    private JTextField portField, message;    private JTextArea display;    private JButton button;    private JLabel label;    private int dataPort;    private boolean trysted;    private Thread receiveThread;    private String host;    private boolean DEBUG = false;    public void init() {        //Get the address of the host we came from.        host = getCodeBase().getHost();        //Execute a job on the event-dispatching thread:        //creating this applet's GUI.        try {            SwingUtilities.invokeAndWait(new Runnable() {                public void run() {                    createGUI();                }            });        } catch (Exception e) {            System.err.println("createGUI didn't successfully complete");        }    }    private void createGUI() {              JPanel contentPane = new JPanel(new GridBagLayout());        JScrollPane textAreaScroller = new JScrollPane();        GridBagConstraints c = new GridBagConstraints();        c.insets = new Insets(5,5,5,5);        message = new JTextField("");        c.fill = GridBagConstraints.HORIZONTAL;        c.gridwidth = GridBagConstraints.REMAINDER;	message.addActionListener(this);        contentPane.add(message, c);        display = new JTextArea(5, 40);        display.setEditable(false);        textAreaScroller.setViewportView(display);        c.weighty = 1.0;        c.fill = GridBagConstraints.BOTH;        contentPane.add(textAreaScroller, c);        label = new JLabel("Enter the port (on host " + host                           + ") to send the request to:",                            JLabel.TRAILING);        c.fill = GridBagConstraints.HORIZONTAL;        c.gridwidth = 1;        c.weighty = 0.0;        contentPane.add(label, c);        portField = new JTextField(6);        portField.addActionListener(this);        c.weightx = 1.0;        contentPane.add(portField, c);        button = new JButton("Connect");	button.addActionListener(this);        c.weightx = 0.0;        contentPane.add(button, c);        contentPane.setBorder(BorderFactory.createCompoundBorder(             BorderFactory.createLineBorder(Color.black),             BorderFactory.createEmptyBorder(5,5,5,5)));        setContentPane(contentPane);    }    public void start() {        start(false);    }        private void start(boolean onEDT) {                if (DEBUG) {            System.out.println("In start() method.");        }        if (receiveThread == null) {            trysted = false;            os = null;            is = null;            socket = null;            receiveThread = new Thread(this);            receiveThread.start();            if (DEBUG) {                System.out.println("  Just set everything to null and started thread.");            }            enableGUI(onEDT);                    } else if (DEBUG) {            System.out.println("  receiveThread not null! Did nothing!");        }    }        //Invoked to reenable the GUI.    private void enableGUI(boolean onEDT) {        if (onEDT) {            enableGUI();        } else {            //Execute a job on the event-dispatching thread:            //Enabling the GUI.            try {                SwingUtilities.invokeAndWait(new Runnable() {                    public void run() {                        enableGUI();                    }                });            } catch (Exception e) {}        }    }        //Assumes it's already on the EDT.    private void enableGUI() {        label.setEnabled(true);        portField.setEnabled(true);        button.setEnabled(true);    }        //Assumes it's already on the EDT.    private void disableGUI() {        label.setEnabled(false);        portField.setEnabled(false);        button.setEnabled(false);    }    public void stop() {        stop(false);    }        private synchronized void stop(boolean onEDT) {        if (DEBUG) {            System.out.println("In stop() method.");        }        receiveThread = null;        trysted = false;        enableGUI(onEDT);        notify();        try { //Close input stream.            if (is != null) {                is.close();                is = null;            }        } catch (Exception e) {} //Ignore exceptions.        try { //Close output stream.            if (os != null) {                os.close();                os = null;            }        } catch (Exception e) {} //Ignore exceptions.        try { //Close socket.            if (socket != null) {                socket.close();                socket = null;            }        } catch (Exception e) {} //Ignore exceptions.    }                //As an event listener, this is invoked on the event-dispatching    //thread, so we can directly manipulate components here.    public void actionPerformed(ActionEvent event) {        int port;                if (DEBUG) {            System.out.println("In actionPerformed() method.");        }        if (receiveThread == null) {            start(true);        }        if (!trysted) {        //We need to attempt a rendezvous.            if (DEBUG) {                System.out.println("  trysted = false. "                                   + "About to attempt a rendezvous.");            }            //Get the port the user entered...            try {                port = Integer.parseInt(portField.getText());            } catch (NumberFormatException e) {                //No integer entered.                 appendToDisplay("Please enter an integer below.\n");                return;            }            if (DEBUG) {                System.out.println("About to attempt rendezvous with port " + port + ".");            }                        //...and rendezvous with it.            rendezvous(port);        } else { //We've already rendezvoused. Just send data over.            if (DEBUG) {                System.out.println("  trysted = true. "                                   + "About to send data.");            }            String str = message.getText();            message.selectAll();            try {                os.write(str);		os.newLine();                os.flush();            } catch (IOException e) {                appendToDisplay("ERROR: Applet couldn't write to socket.\n");                appendToDisplay("...Disconnecting.\n");                stop(true);                return;            } catch (NullPointerException e) {                appendToDisplay("ERROR: No output stream!\n");                appendToDisplay("...Disconnecting.\n");                stop(true);                return;            }            appendToDisplay("SENT TO SERVER: " + str + "\n");        }    }    private synchronized void waitForTryst() {        //Wait for notify() call from action().        try {            wait();                } catch (InterruptedException e) {}        if (DEBUG) {            System.out.println("waitForTryst about to return. "                               + "trysted = " + trysted + ".");        }        return;    }    public void run() {        String received = null;        waitForTryst();        //OK, now we can send messages.        while (Thread.currentThread() == receiveThread) {            try {                 //Wait for data from the server.                received = is.readLine();                //Display it.                if (received != null) {                    appendToDisplay("RECEIVED FROM SERVER: " + received + "\n", false);                } else { //success but no data...                    System.err.println("End of stream?");		    return;                }            } catch (IOException e) { //Perhaps a temporary problem?                appendToDisplay("NOTE: Couldn't read from socket.\n", false);                return;            }        }    }        private void appendToDisplay(String s, boolean onEDT) {        if (onEDT) {            appendToDisplay(s);        } else {            final String newText = s;            //Execute a job on the event-dispatching thread:            //creating this applet's GUI.            try {                SwingUtilities.invokeAndWait(new Runnable() {                    public void run() {                        appendToDisplay(newText);                    }                });            } catch (Exception e) { }        }    }        //Assumes it IS called from the EDT.    private void appendToDisplay(String s) {        display.append(s);        display.setCaretPosition(display.getText().length());    }    //Invoked by actionPerformed, and thus executing on the EDT.    private synchronized void rendezvous(int port) {        //Try to open a socket to the port.        try {            socket = new Socket(host, port);        } catch (UnknownHostException e) {            appendToDisplay("ERROR: Can't find host: " + host + "\n");            return;        } catch (IOException e) {            appendToDisplay("ERROR: Can't open socket on rendezvous port "                           + port + " (on host " + host + ").\n");            return;        }        appendToDisplay("Successfully opened socket on rendezvous port.\n");        //Try to open streams to read and write from the socket.        try {            os = new BufferedWriter(		     new OutputStreamWriter(socket.getOutputStream()));            is = new BufferedReader(		     new InputStreamReader(socket.getInputStream()));        } catch (IOException e) {            appendToDisplay("ERROR: Created data socket but can't "                            + "open stream on it.\n");            appendToDisplay("...Disconnecting.\n");            stop(true);            return;        }           appendToDisplay("Successfully opened I/O streams on rendezvous port.\n");                if ((os != null) & (is != null)) {            if (DEBUG) {                System.out.println("Successful rendezvous.");                System.out.println("socket = " + socket);                System.out.println("output stream = " + os);                System.out.println("input stream = " + is);            }            //Let the main applet thread know we've successfully rendezvoused.            disableGUI();            trysted = true;            notify();        } else {            appendToDisplay("ERROR: Port is valid but communication failed. "                            + "Please TRY AGAIN.\n");        }    }}