import java.awt.*;
import java.awt.event.*;
import java.util.*;
import java.net.*;
import java.io.*;
import javax.swing.*;
import javax.swing.event.*;

public class WebBrowser
{
	public static void main(String [] args)
	{
		JFrame frame = new EditorPaneFrame();
		frame.show();
	}
}
class EditorPaneFrame extends JFrame
{

	private JTextField url;
	private JCheckBox editable;
	private JButton loadButton;
	private JButton backButton;
	private JEditorPane editorPane;
	private Stack urlStack = new Stack();


	public EditorPaneFrame()
	{
		setTitle("Java Web Browser");
		setSize(600,400);
		addWindowListener(new WindowAdapter()
		{
			public void windowClosing(WindowEvent e)
			{
				System.exit(0);
			}
		} );

		// set up text field and load button for typing in URL

		url = new JTextField(30);

		loadButton = new JButton("Load");
		loadButton.addActionListener(new ActionListener()
		{
			public void actionPerformed(ActionEvent event)
			{
				try
				{
					// remember URL for back button
					urlStack.push(url.getText());
					editorPane.setPage(url.getText());
				}
				catch(Exception e)
				{
					editorPane.setText("Error: " +e);
				}
			}
		});

		// set up back button and button action

		backButton = new JButton("Back");
		backButton.addActionListener(new ActionListener()
		{
			public void actionPerformed(ActionEvent event)
			{
				if(urlStack.size()<=1) return;
				try
				{
					urlStack.pop();
					String urlString = (String)urlStack.peek();
					url.setText(urlString);
					editorPane.setPage(urlString);
				}
				catch(IOException e)
				{
					editorPane.setText("Error : " +e);
				}
			}
		});

		editorPane = new JEditorPane();
		editorPane.setEditable(false);
		editorPane.addHyperlinkListener(new HyperlinkListener()
		{
			public void hyperlinkUpdate(HyperlinkEvent event)
			{
				if(event.getEventType() == HyperlinkEvent.EventType.ACTIVATED)
				{
					try
					{
						urlStack.push(event.getURL().toString());
						url.setText(event.getURL().toString());

						editorPane.setPage(event.getURL());
					}
					catch(IOException e)
					{
						editorPane.setText("Error: " + e);
					}
				}
			}
		});

		editable = new JCheckBox();
		editable.addActionListener(new ActionListener()
		{
			public void actionPerformed(ActionEvent event)
			{
				editorPane.setEditable(editable.isSelected());
			}
		});

		Container contentPane = getContentPane();
		contentPane.add(new JScrollPane(editorPane), "Center");

		JPanel panel = new JPanel();
		panel.add(new JLabel("URL"));
		panel.add(url);
		panel.add(loadButton);
		panel.add(backButton);
		panel.add(new JLabel("Editable"));
		panel.add(editable);

		contentPane.add(panel,"South");
	}

}