/**

* Java. Level 2. Lesson 4. Example of homework

*

* @author Sergey Iryupin

* @version 0.1.2 dated Jun 18, 2018

*/

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

import java.io.*;

class HW4Lesson extends JFrame implements ActionListener {

final String TITLE_OF_PROGRAM = "Client for net.chat";

final int WINDOW_WIDTH = 350;

final int WINDOW_HEIGHT = 450;

final String BTN_ENTER = "Enter";

final String LOG_FILE_NAME = "logchat.txt";

JTextArea dialogue; // area for dialog

JTextField message; // field for entering messages

public static void main(String[] args) {

new HW4Lesson();

}

/**

* Constructor:

* Creating a window and all the necessary elements on it

*/

HW4Lesson() {

setTitle(TITLE_OF_PROGRAM);

setDefaultCloseOperation(EXIT_ON_CLOSE);

setSize(WINDOW_WIDTH, WINDOW_HEIGHT);

setLocationRelativeTo(null); // to the center

// area for dialog

dialogue = new JTextArea();

dialogue.setEditable(false);

JScrollPane scrollBar = new JScrollPane(dialogue);

// panel for checkbox, message field and button

JPanel bp = new JPanel();

bp.setLayout(new BoxLayout(bp, BoxLayout.X_AXIS));

message = new JTextField();

message.addActionListener(this);

JButton enter = new JButton(BTN_ENTER);

enter.addActionListener(this);

// adding all elements to the window

bp.add(message);

bp.add(enter);

add(BorderLayout.CENTER, scrollBar);

add(BorderLayout.SOUTH, bp);

setVisible(true);

}

/**

* Listener of events from message field and enter button

*/

@Override

public void actionPerformed(ActionEvent event) {

if (message.getText().trim().length() > 0) {

dialogue.append(message.getText() + "\n");

try (PrintWriter pw =

new PrintWriter(new FileWriter(LOG_FILE_NAME, true))) {

pw.println(message.getText());

pw.flush();

} catch (IOException ex) { }

}

message.setText("");

message.requestFocusInWindow();

}

}