import java.awt.*;
import corejava.*;

/* A subclass of TextField for entering doubles.  Based on Core Java's IntTextField. */

public class DoubleTextField extends TextField
{
	/**
	* Creates the text field
	* @param def a double default,
	* @param min the minimum double accepted
	* @param max the maximum double accepted
	* @param size the size of the text field
	*/
	
	public DoubleTextField (double def, double min, double max, int size)
	{
		super ("" + def, size);
		low = min;
		high = max;
	}

	/**
	* Checks if the data entered is valid or not
	* @return true data ok, false otherwise
	* @remark if invalid, the field gets focus so the user can fix it
	*/
	
	public boolean isValid ()
	{
		double value;  
		try
		{
			value = Double.valueOf (getText ().trim ()).doubleValue ();
			if (value < low || value > high)
				throw new NumberFormatException ();
		}
		catch (NumberFormatException e)
		{
			requestFocus ();
			return false;
		}
      return true; 
   }

	/**
	* Get the double data value
	* @return the double data value
	* @remark if invalid, returns the valid prefix (or 0 if none)
	*/
	
	public double getValue()
	{
		return Format.atof (getText ());
	}

	private double low;	/* min value allowed */
	private double high;	/* max value allowed */
}