/*
 * A simple Java program that demonstrates how cut/copy/paste works.
 *
 * Ben Bederson, May 3, 2002
 *
 * Bugs - Can't paste text from a webpage
 */
import java.io.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.dnd.*;
import java.awt.datatransfer.*;
import javax.swing.*;
import javax.swing.text.*;

public class CopyPasteExample extends JFrame {
    JMenuBar menuBar;
    JTextArea textArea;

    public CopyPasteExample() {
	setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

				// Create a menu
	menuBar = new JMenuBar();
	JMenu fileMenu = new JMenu("File");
	fileMenu.add(new AbstractAction("Exit") {
		public void actionPerformed(ActionEvent e) {
		    System.exit(0);
		}
	    });
	JMenu editMenu = new JMenu("Edit");
	editMenu.add(new AbstractAction("Cut") {
		public void actionPerformed(ActionEvent e) {
		    cut();
		}
	    });
	editMenu.add(new AbstractAction("Copy") {
		public void actionPerformed(ActionEvent e) {
		    copy();
		}
	    });
	editMenu.add(new AbstractAction("Paste") {
		public void actionPerformed(ActionEvent e) {
		    Clipboard clipboard = Toolkit.getDefaultToolkit().getSystemClipboard();
		    Transferable transferable = clipboard.getContents(null);
		    paste(transferable);
		}
	    });
	menuBar.add(fileMenu);
	menuBar.add(editMenu);

	                        // Create a text box 
	textArea = new JTextArea();
	textArea.setRows(20);
	textArea.setColumns(50);
	JScrollPane scrollPane = new JScrollPane(textArea);
		
				// Set up the GUI
	setJMenuBar(menuBar);
	getContentPane().add(scrollPane);
	pack();           // Calculate the size of the window
	setVisible(true); // Make the window visible
    }

    public void cut() {
	copy();
	deleteSelection();
    }

    public Transferable copy() {
	Transferable transferable = null;
	try {
	    int start = textArea.getSelectionStart();
	    int end = textArea.getSelectionEnd();
	    transferable = new StringSelection(textArea.getText(start, end-start));
	    Clipboard clipboard = Toolkit.getDefaultToolkit().getSystemClipboard();
	    clipboard.setContents(transferable, null);
	} catch (BadLocationException e) {
	    System.out.println("Internal error selecting text");
	}

	return transferable;
    }

    public void paste(Transferable transferable) {
	/*
	DataFlavor[] flavors = transferable.getTransferDataFlavors();
	for (int i=0; i<flavors.length; i++) {
	    System.out.println("flavor = " + flavors[i]);
	}
	*/

	// Warning - this is buggy for JDK1.3 (complains about not supporting unicode flavors)
	// but it works fine with JDK1.4

	try {
	    deleteSelection();

	    Object obj;
	    try {
		Reader reader = DataFlavor.stringFlavor.getReaderForText(transferable);
		BufferedReader bufferedReader = new BufferedReader(reader);

		String str = "";
		String temp;
		do {
		    temp = bufferedReader.readLine();
		    if (temp != null) {
			str += temp + "\n";
		    }
		} while (temp != null);

		textArea.insert(str, textArea.getCaretPosition());
	    } catch (InvalidDnDOperationException e) {
		System.out.println("Can't paste with plain text flavor");
	    }
	} catch (UnsupportedFlavorException e) {
	    System.out.println("Can't paste clipboard as text: " + e);
	} catch (IOException e) {
	    System.out.println("Can't paste clipboard as text: " + e);
	}
    }

    protected void deleteSelection() {
	try {
	    int start = textArea.getSelectionStart();
	    int end = textArea.getSelectionEnd();
	    if (end > start) {
		String temp = "";
		if (start > 0) {
		    temp = textArea.getText(0, start);
		}
		int len = textArea.getText().length();
		temp += textArea.getText(end, len - end);
		int caret = textArea.getCaretPosition();
		if ((caret > start) && (caret < end)) {
		    caret = start;
		} else if (caret >= end) {
		    caret -= (end - start);
		}
		textArea.setText(temp);
		textArea.setCaretPosition(caret);
	    }
	} catch (BadLocationException e) {
	    System.out.println("Internal error deleting selection");
	}
    }

    public static void main(String[] args) {
	new CopyPasteExample();
    }
}