/*
 * Copyright 2006 (C) Jeffrey Palm
 *
 * This code is licensed under the GPL.
 */

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

/**
 * A simple class to display a keyboard that copies keystrokes
 * to the clipboard so that if your keyboard dies you can still
 * type.
 *
 * @author Jeffrey Palm
 */
public class Keyboard {

  public static void main(String[] args) {
    new Keyboard().realMain(args);
  }

  void realMain(String[] args) {
    //
    // The gui stuff
    //
    final TextTransfer tt = new TextTransfer();
    final JLabel contents = new JLabel(tt.getClipboardContents());
    JFrame f = new JFrame("Keyboard");
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    f.getContentPane().setLayout(new BoxLayout(f.getContentPane(),BoxLayout.Y_AXIS));
    JPanel p; // we'll reuse this
    p = newPanel();
    p.add(new JLabel("Contents: "));
    p.add(contents);
    f.getContentPane().add(p);
    final JCheckBox caps = new JCheckBox("Caps");
    final boolean[] checked = new boolean[1]; 
    caps.addItemListener(new ItemListener() {
        public void itemStateChanged(ItemEvent e) {
          checked[0] = e.getStateChange() == ItemEvent.SELECTED;
        }
      });
    char[][] keys = {
      {'~','!','@','#','$','%','^','&','*','(','0','_','+'},
      {'`','1','2','3','4','5','6','7','8','9','0','-','='},
      {'Q','W','E','R','T','Y','U','I','O','P','[','{',']','}'},
      {'A','S','D','F','G','H','J','K','L',';',':','\'','"',','},
      {'Z','X','C','V','B','N','M',',','<','.','>','/','?'}
    };
    for (int i=0; i<keys.length; i++) {
      char[] row = keys[i];
      p = newPanel();
      for (int j=0; j<row.length; j++) {
        final char key = row[j];
        JButton b = new JButton(new AbstractAction(String.valueOf(key)) {
            public void actionPerformed(ActionEvent e) {              
              char c;
              // check whether to make this lowercase
              if (Character.isLetter(key) && !checked[0]) {
                c = Character.toLowerCase(key);
              } else {
                c = key;
              }
              String k = String.valueOf(c);
              tt.setClipboardContents(k);
              contents.setText(k);
            }
          });
        p.add(b);
      }
      f.getContentPane().add(p);
    }
    p = newPanel();
    p.add(caps);
    f.getContentPane().add(p);
    f.pack();
    f.setVisible(true);
  }

  private JPanel newPanel() {
    JPanel p = new JPanel();
    p.setLayout(new FlowLayout(FlowLayout.LEFT));
    return p;
  }
 

  /**
   * Taken from: http://www.javapractices.com/Topic82.cjp
   */
  final static class TextTransfer implements ClipboardOwner {

    /**
     * Empty implementation of the ClipboardOwner interface.
     */
    public void lostOwnership( Clipboard aClipboard, Transferable aContents) {
      //do nothing
    }

    /**
     * Place a String on the clipboard, and make this class the
     * owner of the Clipboard's contents.
     */
    public void setClipboardContents( String aString ){
      StringSelection stringSelection = new StringSelection( aString );
      Clipboard clipboard = Toolkit.getDefaultToolkit().getSystemClipboard();
      clipboard.setContents( stringSelection, this );
    }

    /**
     * Get the String residing on the clipboard.
     *
     * @return any text found on the Clipboard; if none found, return an
     * empty String.
     */
    public String getClipboardContents() {
      String result = "";
      Clipboard clipboard = Toolkit.getDefaultToolkit().getSystemClipboard();
      //odd: the Object param of getContents is not currently used
      Transferable contents = clipboard.getContents(null);
      boolean hasTransferableText =
        (contents != null) &&
        contents.isDataFlavorSupported(DataFlavor.stringFlavor)
        ;
      if ( hasTransferableText ) {
        try {
          result = (String)contents.getTransferData(DataFlavor.stringFlavor);
        }
        catch (UnsupportedFlavorException ex){
          //highly unlikely since we are using a standard DataFlavor
          System.out.println(ex);
          ex.printStackTrace();
        }
        catch (IOException ex) {
          System.out.println(ex);
          ex.printStackTrace();
        }
      }
      return result;
    }
  }
}