/* * Copyright (c) 2000 David Flanagan.  All rights reserved. * This code is from the book Java Examples in a Nutshell, 2nd Edition. * It is provided AS-IS, WITHOUT ANY WARRANTY either expressed or implied. * You may study, use, and modify it for any non-commercial purpose. * You may distribute it non-commercially as long as you retain this notice. * For a commercial use license, or to purchase the book (recommended), * visit http://www.davidflanagan.com/javaexamples2. */package com.davidflanagan.examples.datatransfer;import java.awt.*;import java.awt.event.*;import java.awt.datatransfer.*;/** * This program demonstrates how to add simple copy-and-paste capabilities * to an application. **/public class SimpleCutAndPaste extends Frame implements ClipboardOwner{    /** The main method creates a frame and pops it up. */    public static void main(String[] args) {	Frame f = new SimpleCutAndPaste();	f.addWindowListener(new WindowAdapter() { 		public void windowClosing(WindowEvent e) { System.exit(0); }	    });	f.pack();	f.setVisible(true);    }        /** The text field that holds the text that is cut or pasted */    TextField field;        /**     * The constructor builds a very simple test GUI, and registers this object     * as the ActionListener for the buttons      **/    public SimpleCutAndPaste() {	super("SimpleCutAndPaste");  // Window title	this.setFont(new Font("SansSerif", Font.PLAIN, 18)); // Use a big font		// Set up the Cut button	Button copy = new Button("Copy");                       	copy.addActionListener(new ActionListener() {		public void actionPerformed(ActionEvent e) { copy(); }	    });	this.add(copy, "West");		// Set up the Paste button	Button paste = new Button("Paste");	paste.addActionListener(new ActionListener() {		public void actionPerformed(ActionEvent e) { paste(); }	    });	this.add(paste, "East");		// Set up the text field that they both operate on	field = new TextField();	this.add(field, "North");    }        /**     * This method takes the current contents of the text field, creates a     * StringSelection object to represent that string, and puts the      * StringSelection onto the clipboard     **/    public void copy() {	// Get the currently displayed value	String s = field.getText();                  		// Create a StringSelection object to represent the text.	// StringSelection is a pre-defined class that implements	// Transferable and ClipboardOwner for us. 	StringSelection ss = new StringSelection(s); 		// Now set the StringSelection object as the contents of the clipboard	// Also specify that we're the clipboard owner	this.getToolkit().getSystemClipboard().setContents(ss, this);	// Highlight the text to indicate it is on the clipboard.	field.selectAll();    }        /**     * Get the contents of the clipboard, and, if we understand the type,     * display the contents.  This method understands strings and file lists.     **/    public void paste() {	// Get the clipboard	Clipboard c = this.getToolkit().getSystemClipboard();		// Get the contents of the clipboard, as a Transferable object	Transferable t = c.getContents(this);	// Find out what kind of data is on the clipboard	try { 	    if (t.isDataFlavorSupported(DataFlavor.stringFlavor)) {		// If it is a string, then get and display the string		String s = (String) t.getTransferData(DataFlavor.stringFlavor);		field.setText(s); 			    }	    else if (t.isDataFlavorSupported(DataFlavor.javaFileListFlavor)) {		// If it is a list of File objects, get the list and display		// the name of the first file on the list		java.util.List files = (java.util.List)		    t.getTransferData(DataFlavor.javaFileListFlavor);		java.io.File file = (java.io.File)files.get(0);		field.setText(file.getName());	    }	}	// If anything goes wrong with the transfer, just beep and do nothing.	catch (Exception e) { this.getToolkit().beep(); }    }    /**     * This method implements the ClipboardOwner interface.  It is called when     * something else is placed on the clipboard.     **/    public void lostOwnership(Clipboard c, Transferable t) {	// Un-highlight the text field, since we don't "own" the clipboard	// anymore, and the text is no longer available to be pasted.	field.select(0,0);    }}