import java.awt.*;
import java.lang.*;
import java.util.*;
import java.io.*;
import corejava.*;
import java.net.*;
import java.applet.*;


// this function enables  textfield interface to accept double value //
public class DoubleTextField extends TextField
{


// constructor :  def = value to be displayed, min = min acceptable value, max = max acceptable value, size //= length of interface 
   public DoubleTextField(double def, double min, double max,
      int size)
   {  super("" + def, size);
      low  = min;
      high = max;
   }

// return true if the value are between min  and max; otherwise return false  //
   public boolean isValid()
   {  double value;
      try
      {  value = (double)(Format.atof(getText()));
         if (value < low || value > high)
            throw new NumberFormatException();
      }
      catch (NumberFormatException e)
      {  requestFocus();
         return false;
      }
      return true;
   }

// return the value as double from the interface //
   public double getValue()
   {  return (double)(Format.atof(getText()));  }

   private double low;
   private double high;
}