validationtest.java

Java2核心技术卷一 配套源码,看了还不错

/**
 * @version 1.20 2 Jul 1998
 * @author Cay Horstmann
 */

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

class ValidationTestFrame extends JFrame
   implements DocumentListener
{  public ValidationTestFrame()
   {  setTitle("ValidationTest");
      setSize(300, 200);
      addWindowListener(new WindowAdapter()
      {  public void windowClosing(WindowEvent e)
         {  System.exit(0);
         }
      } );

      Container contentPane = getContentPane();

      JPanel p = new JPanel();
      hourField = new IntTextField(12, 3);
      p.add(hourField);
      hourField.getDocument().addDocumentListener(this);
      
      minuteField = new IntTextField(0, 3);
      p.add(minuteField);
      minuteField.getDocument().addDocumentListener(this);
  
      contentPane.add(p, "South");
      clock = new ClockPanel();
      contentPane.add(clock, "Center");
   }
   
   public void insertUpdate(DocumentEvent e)
   {  setClock();
   }
   public void removeUpdate(DocumentEvent e)
   {  setClock();
   }
   public void changedUpdate(DocumentEvent e)
   {  
   }
    
   public void setClock()
   {  if (hourField.isValid() && minuteField.isValid())
      {  int hours = hourField.getValue();
         int minutes = minuteField.getValue();
         clock.setTime(hours, minutes);
      }
   }
      
   private IntTextField hourField;
   private IntTextField minuteField;
   private ClockPanel clock;
}

class ClockPanel extends JPanel
{  public void paintComponent(Graphics g)
   {  super.paintComponent(g); 
      g.drawOval(0, 0, 100, 100);
      double hourAngle 
         = 2 * Math.PI * (minutes - 3 * 60) / (12 * 60);
      double minuteAngle 
         = 2 * Math.PI * (minutes - 15) / 60;
      g.drawLine(50, 50, 
         50 + (int)(30 * Math.cos(hourAngle)), 
         50 + (int)(30 * Math.sin(hourAngle)));
      g.drawLine(50, 50, 
         50 + (int)(45 * Math.cos(minuteAngle)), 
         50 + (int)(45 * Math.sin(minuteAngle)));
   }
   
   public void setTime(int h, int m)
   {  minutes = h * 60 + m;
      repaint();
   }
   
   public void tick()
   {  minutes++;  
      repaint();
   }
   
   private int minutes = 0;
}

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

class IntTextDocument extends PlainDocument
{  public void insertString(int offs, String str, 
      AttributeSet a) 
      throws BadLocationException 
   {  if (str == null) return;
      String oldString = getText(0, getLength());
      String newString = oldString.substring(0, offs)
         + str + oldString.substring(offs);
      try
      {  Integer.parseInt(newString + "0");
         super.insertString(offs, str, a);
      }
      catch(NumberFormatException e)
      {  
      }
   }
}

class IntTextField extends JTextField 
{  public IntTextField(int defval, int size)
   {  super("" + defval, size);
   }

   protected Document createDefaultModel() 
   {  return new IntTextDocument();
   }

   public boolean isValid()
   {  try
      {  Integer.parseInt(getText());
         return true;
      }
      catch(NumberFormatException e)
      {  return false; 
      }
   }

   public int getValue()
   {  try
      {  return Integer.parseInt(getText());
      }
      catch(NumberFormatException e)
      {  return 0; 
      }
   }
}