/*
 *  =======================================================================
 *  DemoTextArea.java : This applet exercises the capabilities of the class
 *  JTextArea. The contents of the text area may be manipulated by using 
 *  the text field and buttons displayed. A message may be typed in the
 *  text field box and then positioned using the button operations.
 *  You can also select a text segment and press delete to remove it. Other
 *  buttons are used for cat, copy and paste.
 *
 *  Adapted from : Pantham S., Pure JFC Swing, 1999.
 *  Modified by : Mark Austin                                   March, 2001
 *  =======================================================================
 */

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public class DemoTextArea extends JApplet {

    // 1. Declare the references for the following objects.

    Container container;
    JLabel label = null;
    JTextField textField = null;
    JTextArea textArea   = null;
    JButton insertButton = null;
    JButton deleteButton = null;
    JButton cutButton    = null;
    JButton copyButton   = null;
    JButton pasteButton  = null;

    public void init() {

        // 2. Get a handle to the applet's container.

        Container container = this.getContentPane();

        // 3. Create the fonts for label and text area.

        Font labelFont = new Font("SanSerif", Font.BOLD, 14);
        Font textFont = new Font("Dialog", Font.PLAIN, 12);

        // 4. Use the gridbag layout for the applet.

        GridBagLayout gridbag = new GridBagLayout();
        container.setLayout(gridbag);
        GridBagConstraints c = new GridBagConstraints();

        // 5. Add a label.

        c.fill   = c.BOTH;
        c.insets = new Insets(2,2,2,2);
        c.gridx  = 0; c.gridy = 0;
        c.gridwidth = 5; c.gridheight = 1;
        c.anchor  = c.WEST;
        c.weightx = 1.0; c.weighty = 1.0;
        label = new JLabel("Enter Text: ");
        label.setFont(labelFont);
        gridbag.setConstraints(label, c);
        container.add(label);  // add the label

        // 6. Add a text field.

        c.anchor = c.CENTER;
        c.gridx = 0; c.gridy = 1;
        textField = new JTextField();
        gridbag.setConstraints(textField, c);
        container.add(textField);  // add the text-field

        // 7. Add the Insert button.

        c.gridx = 0; c.gridy = 2;
        c.gridwidth = 1; c.gridheight = 1;
        c.fill = c.BOTH; 
        insertButton = new JButton("Insert");
        insertButton.setBackground(Color.lightGray);
        gridbag.setConstraints(insertButton, c);
        container.add(insertButton);  // add insert button
        ButtonListener inButtonListener = new ButtonListener();
        insertButton.addActionListener(inButtonListener);

        // 8. Add the Delete button.

        c.gridx = 1; c.gridy = 2;
        deleteButton = new JButton("Delete");
        deleteButton.setBackground(Color.lightGray);
        gridbag.setConstraints(deleteButton, c);
        container.add(deleteButton); // add the delete button
        ButtonListener dlButtonListener = new ButtonListener();
        deleteButton.addActionListener(dlButtonListener);

        // 9. Add the Cut button.

        c.gridx = 2; c.gridy = 2;
        cutButton = new JButton("Cut");
        cutButton.setBackground(Color.lightGray);
        gridbag.setConstraints(cutButton, c);
        container.add(cutButton); // add the cut button
        ButtonListener ctButtonListener = new ButtonListener();
        cutButton.addActionListener(ctButtonListener);

        // 10. Add the Copy button.

        c.gridx = 3; c.gridy = 2;
        copyButton = new JButton("Copy");
        copyButton.setBackground(Color.lightGray);
        gridbag.setConstraints(copyButton, c);
        container.add(copyButton); // add the copy button
        ButtonListener cpButtonListener = new ButtonListener();
        copyButton.addActionListener(cpButtonListener);

        // 11. Add the Paste button.

        c.gridx = 4; c.gridy = 2;
        pasteButton = new JButton("Paste");
        pasteButton.setBackground(Color.lightGray);
        gridbag.setConstraints(pasteButton, c);
        container.add(pasteButton); // add the paste button
        ButtonListener psButtonListener = new ButtonListener();
        pasteButton.addActionListener(psButtonListener);

        // 12. Add the text area.

        c.gridx = 0;     c.gridy = 3;
        c.gridwidth = 5; c.gridheight = 3;
        c.weightx = 1.0; c.weighty = 1.0;
        c.anchor = c.CENTER;
        c.fill   = c.BOTH;
        String someText = "The Swing 'JTextArea' is a " + "light-weight component.";
        textArea = new JTextArea(someText, // To be displayed initially
                                 20,  // Number of rows.
                                 30); // Number of columns.

        textArea.setFont(textFont);
        textArea.setBackground(Color.white);
        textArea.setSelectionColor(Color.yellow);
        textArea.setTabSize(5); // The tab size.
        textArea.setLineWrap(true); // Wrap the line at the container end.

        JScrollPane scrollPane = new JScrollPane(textArea);

        gridbag.setConstraints(scrollPane, c);

        container.add(scrollPane); // Add the text area.
    }

    // 13. Button listener class.

    class ButtonListener implements ActionListener {

        public void actionPerformed(ActionEvent e) {
            JButton b = (JButton) e.getSource();

            if (b == insertButton) {
                try { 
                    // Insert text at the caret position. The text is 
                    // is retrieved from the text field by using getText().
                    textArea.insert(textField.getText(),
                                    textArea.getCaretPosition());
                }
                catch (IllegalArgumentException excep) {
                }
            }

            else if (b == deleteButton) {
                textArea.replaceSelection(""); // Selected text is deleted.
            }
            else if (b == cutButton) {
                textArea.cut();   // JTextArea cut operation.
            }
            else if (b == copyButton) {
                textArea.copy();  // JTextArea copy operation.
            }
            else if (b == pasteButton) {
                textArea.paste(); // JTextArea paste operation.
            }
        }
    }
}