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

class JumpDialog extends JDialog {
    private JButton jumpButton = new JButton("Jump");
    private JButton cancelButton = new JButton("Cancel");
    private JLabel label = new JLabel(" Jump To Step: ");
    private JTextField jtf = new JTextField(10);
    private JCheckBox jcb = new JCheckBox("Jump to End");

    private JPanel buttonPane = new JPanel();
    private JPanel inputPane = new JPanel();

    private Box b;

    private int j;
    private boolean valid;

    JDialog dialog = this;

    public JumpDialog(Frame owner, String message) {
	super(owner, message, true);

	buttonPane.setLayout(new BoxLayout(buttonPane, BoxLayout.X_AXIS));
	buttonPane.add(jumpButton);
	buttonPane.add(cancelButton);


	jumpButton.addActionListener(new JumpValueListener());

	cancelButton.addActionListener(new ActionListener() {
	    public void actionPerformed(ActionEvent e) {
		dialog.dispose();
	    }
	});

	jcb.addActionListener(new ActionListener() {
	    public void actionPerformed(ActionEvent e) {
		if(jcb.isSelected()) {
		    jtf.setEnabled(false);
		} else {
		    jtf.setEnabled(true);
		}
	    }
	});

	inputPane.setLayout(new BoxLayout(inputPane, BoxLayout.X_AXIS));
	inputPane.add(label);
	inputPane.add(jtf);
	inputPane.setMaximumSize(new Dimension(200, 100));

	b = new Box(BoxLayout.Y_AXIS);		 

	b.add(Box.createVerticalGlue());
	b.add(inputPane);
	b.add(Box.createVerticalGlue());
	b.add(jcb);
	b.add(Box.createVerticalGlue());
	b.add(buttonPane);
	getContentPane().add(b);
	setLocationRelativeTo(owner);
	setSize(new Dimension(200, 120));
	setResizable(false);
	getRootPane().setDefaultButton(jumpButton);
    }

    public void show() {
	valid = false;
	super.show();
    }

    public int getJump() {
	return j;
    }

    public boolean isValid() {
	return valid;
    }
    
    class JumpValueListener implements ActionListener {
	public void actionPerformed(ActionEvent e) {
	    if(!jcb.isSelected()) {
		try {
		    j = Integer.valueOf(jtf.getText()).intValue();
		} catch (NumberFormatException exc) {
		    JOptionPane.showMessageDialog(dialog,
						  "Please enter a positive integer",
						  "Bad Format",
						  JOptionPane.ERROR_MESSAGE,
						  null);
		    return;
		}
		if(j < 1) {
		    JOptionPane.showMessageDialog(dialog,
						  "Please enter a positive integer",
						  "Bad Format",
						  JOptionPane.ERROR_MESSAGE,
						  null);
		    return;
		}
	    } else {
		j = -1;
	    }
	    valid = true;
	    dialog.dispose();
	}
    }
}