// Fig. 27.7: Client.java
// Client portion of a stream-socket connection between client and server

import java.io.*;
import java.net.InetAddress;
import java.net.Socket;
import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;

public class Client extends JFrame {

    private JTextField enterField;      // enters information from user
    private JTextArea displayArea;      // display information to user
    private ObjectOutputStream output;  // output stream to server
    private ObjectInputStream input;    // input stream from server
    private String message = "";        // message from server
    private String chatServer;          // host server for this application
    private Socket client;              // socket to communicate with server

    // initialize chatServer and set up GUI
    public Client(String host) {
        super("Client");
        chatServer = host;              // set server to which this client connects
        enterField = new JTextField();  // create enterField
        enterField.setEditable(false);
        enterField.addActionListener(
                new ActionListener() {
                    // send message to server
                    public void actionPerformed(ActionEvent event) {
                        sendData(event.getActionCommand());
                        enterField.setText("");
                    } // end method actionPerformed
                }       // end anonymous inner class
                );      // end call to addActionListener
        add(enterField, BorderLayout.NORTH);
        displayArea = new JTextArea();  // create displayArea
        add(new JScrollPane(displayArea), BorderLayout.CENTER);
        setSize(300, 250);              // set size of window
        setLocation(0, 0);              // set location
        setVisible(true);               // show window
    } // end Client constructor

    // connect to server and process messages from server
    public void runClient() {
        try {   // connect to server, get streams, process connection
            connectToServer();
            // create a Socket to make connection
            getStreams();           // get the input and output streams
            processConnection();    // process connection
        } // end try
        catch (EOFException eofException) {
            displayMessage("\nClient terminated connection");
        } // end catch
        catch (IOException ioException) {
            ioException.printStackTrace();
        } // end catch
        finally {
            closeConnection();      // close connection
        } // end finally
    } // end method runClient

    // connect to server
    private void connectToServer() throws IOException {
        displayMessage("Attempting connection\n");
        // create Socket to make connection to server
        try {
            client = new Socket(InetAddress.getByName(chatServer), 12345);
        } catch (java.net.ConnectException connectException) {
            displayMessage("\nCould not find server");
            throw new EOFException();    //FOO
        }
        // display connection information
        displayMessage("Connected to: " + client.getInetAddress().getHostName());
    } // end method connectToServer

    // get streams to send and receive data
    private void getStreams() throws IOException {
        // set up output stream for objects
        output = new ObjectOutputStream(client.getOutputStream());
        output.flush();     // flush output buffer to send header information
        // set up input stream for objects
        input = new ObjectInputStream(client.getInputStream());
        displayMessage("\nGot I/O streams\n");
    } // end method getStreams

    // process connection with server
    private void processConnection() throws IOException {
        // enable enterField so client user can send messages
        setTextFieldEditable(true);
        do {            // process messages sent from server
            try {       // read message and display it
                message = (String) input.readObject();  // read new message
                displayMessage("\n" + message);         // display message
            } // end try
            catch (ClassNotFoundException classNotFoundException) {
                displayMessage("\nUnknown object type received");
            } // end catch
            catch (java.net.SocketException socketException) {
                displayMessage("\nLost connection to server!");    ///FOO
                break;
            }
        } while (!message.equalsIgnoreCase("SERVER>>> TERMINATE"));
    } // end method processConnection

    // close streams and socket
    private void closeConnection() {
        displayMessage("\nClosing connection");
        setTextFieldEditable(false);    // disable enterField
        try {
            if (output != null)
                output.close();         // close output stream
            if (input != null)
                input.close();          // close input stream 1
            if (client != null)
                client.close();         // close socket
        } // end try
        catch (IOException ioException) {
            ioException.printStackTrace();
        } // end catch
    } // end method closeConnection

    // send message to server
    private void sendData(String message) {
        try {  // send object to server
            output.writeObject("CLIENT>>> " + message);
            output.flush(); // flush data to output
            displayMessage("\nCLIENT>>> " + message);
        } // end try
        catch (IOException ioException) {
            displayArea.append("\nError writing object");
        } // end catch
    } // end method sendData

    // manipulates displayArea in the event-dispatch thread
    private void displayMessage(final String messageToDisplay) {
        SwingUtilities.invokeLater(
                new Runnable() {
                    public void run() {  // updates displayArea
                        displayArea.append(messageToDisplay);
                    } // end method run
                } // end anonymous inner class
                ); // end call to SwingUtilities.invokeLater
    } // end method displayMessage

    // manipulates enterField in the event-dispatch thread
    private void setTextFieldEditable(final boolean editable) {
        SwingUtilities.invokeLater(
                new Runnable() {

                    public void run() {  // sets enterField's editability
                        enterField.setEditable(editable);
                    } // end method run
                }       // end anonymous inner class
                );      // end call to SwingUtilities.invokeLater
    } // end method setTextFieldEditable

} // end class Client