doubletype.java

老外的在线考试

/*
 * Core - Library of useful classes that are used in many CyberDemia projects.
 * Copyright (C) 2003 CyberDemia Research and Services
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 * 
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA  02111-1307, USA.
 *
 * See the COPYING file located in the top-level-directory of
 * the archive of this library for complete text of license.
 */
package com.cyberdemia.value;
import java.io.Serializable;

/**
* <p>
* DoubleType is a wrapper around a primitive double. 
* This differs from <code>java.lang.Double</code> in that it is mutable.
* </p>
* <p>
* It adopts a simple Javabean pattern so that this and any derived classes
* can be used as a Javabean with a property named <i>value</i>. 
* </p>
*
* @author  Alexander Yap
* @version $Revision: 1.3 $ at $Date: 2004/03/12 16:42:50 $ by $Author: alexycyap $
*/
public class DoubleType implements IValueType,Serializable,Cloneable, Comparable
{
	private double m_value = 0.0;
	
	/**
	* Default constructor
	*/
	public DoubleType() 
    { 
	    // Not used
    }
	
	/**
	* Convenient constructor.
	*/
	public DoubleType( double val)
	{
		m_value = val;
	}

	/**
	* Sets the value as a double. This method should map to 
	* property <i>value</i> when this object is used as a JavaBean.
	*
	* @param val  Value to set.
	*/
	public void setValue( double val )
	{
		setDoubleValue(val);
	}
	
	/**
	* Gets the value as a double. This method should map to 
	* property <i>value</i> when this object is used as a JavaBean.
	*
	* @return  Value of this object as a double.
	*/
	public double getValue()
	{
		return getDoubleValue();
	}

	/**
	* Sets the value as a double.
	* @param val  Value to set.
	*/
	public void setDoubleValue( double val )
	{
		m_value = val;
	}

	/**
	* Sets the value as a float.
	* @param val  Value to set.
	*/
	public void setFloatValue( float val )
	{
		m_value = val;
	}

	/**
	* Sets the value as a long.
	* @param val  Value to set.
	*/
	public void setLongValue( long val )
	{
		m_value = val;
	}

	/**
	* Sets the value as an int.
	* @param val  Value to set.
	*/
	public void setIntValue( int val )
	{
		m_value = val;
	}

	/**
	* Sets the value as a short.
	* @param val  Value to set.
	*/
	public void setShortValue( short val )
	{
		m_value = val;
	}

	/**
	* Sets the value as a char.
	* @param val  Value to set.
	*/
	public void setCharValue( char val )
	{
		m_value = val;
	}

	/**
	* Sets the value as a byte.
	* @param val  Value to set.
	*/
	public void setByteValue( byte val )
	{
		m_value = val;
	}

	/**
	* Sets the value as a String.
	* @param val  Value to set.
	*/
	public void setStringValue( String val )
	{
		try
		{
			m_value = Double.parseDouble(val);
		}
		catch (NumberFormatException nfex)
		{
			m_value = Double.NaN;
		}
	}

	/**
	* Gets the value as a double.
	* @return  Value of this object as a double.
	*/
	public double getDoubleValue()
	{
		return m_value;
	}

	/**
	* Gets the value as a float.
	* @return  Value of this object as a float.
	*/
	public float getFloatValue()
	{
		return (float)m_value;
	}

	/**
	* Gets the value as a long.
	* @return  Value of this object as a long.
	*/
	public long getLongValue()
	{
		return (long)m_value;
	}

	/**
	* Gets the value as an int.
	* @return  Value of this object as an int.
	*/
	public int getIntValue()
	{
		return (int)m_value;
	}

	/**
	* Gets the value as a short.
	* @return  Value of this object as a short.
	*/
	public short getShortValue()
	{
		return (short)m_value;
	}

	/**
	* Gets the value as a char.
	* @return  Value of this object as a char.
	*/
	public char getCharValue()
	{
		return (char)m_value;
	}

	/**
	* Gets the value as a byte.
	* @return  Value of this object as a byte.
	*/
	public byte getByteValue()
	{
		return (byte)m_value;
	}

	/**
	* Gets the value as a String.
	* @return  Value of this object as a String.
	*/
	public String getStringValue()
	{
		return String.valueOf(m_value);
	}
	
	/**
	* Adds this object with another IValueType.
	* @param val2   IValueType to add.
	*/
	public void add( IValueType val2 )
	{
		m_value += val2.getDoubleValue();
	}

	/**
	* Adds this object with a double.
	* @param val2   double to add.
	*/
	public void add( double val2 )
	{
		m_value += val2;
	}

	/**
	* Subtracts another IValueType from this object.
	* @param val2   IValueType to subtract.
	*/
	public void subtract( IValueType val2 )
	{
		m_value -= val2.getDoubleValue();
	}

	/**
	* Subtracts a double from this object.
	* @param val2   double to subtract.
	*/
	public void subtract( double val2 )
	{
		m_value -= val2;
	}

	/**
	* Multiplies this object with another IValueType.
	* @param val2   IValueType to multiply with.
	*/
	public void multiply( IValueType val2 )
	{
		m_value *= val2.getDoubleValue();
	}

	/**
	* Multiplies this object with a Number.
	* @param val2   Number to multiply with.
	*/
	public void multiply( Number val2 )
	{
		m_value *= val2.doubleValue();
	}

	/**
	* Multiplies this object with a double.
	* @param val2   double to multiply with.
	*/
	public void multiply( double val2 )
	{
		m_value *= val2;
	}

	/**
	* Divides this object with another IValueType.
	* @param val2   IValueType to divide.
	*/
	public void divide( IValueType val2 )
	{
		if (Math.abs(val2.getDoubleValue()) <= Double.MIN_VALUE)
			m_value = Double.POSITIVE_INFINITY;
		else
			m_value /= val2.getDoubleValue();
	}

	/**
	* Divides this object with a double.
	* @param val2   double to divide.
	*/
	public void divide( double val2 )
	{
		if (Math.abs(val2) <= Double.MIN_VALUE)
			m_value = Double.POSITIVE_INFINITY;
		else
			m_value /= val2;
	}

	/**
	* Divides this object with a Number.
	* @param val2   Number to divide.
	*/
	public void divide( Number val2 )
	{
		if (Math.abs(val2.doubleValue()) <= Double.MIN_VALUE )
			m_value = Double.POSITIVE_INFINITY;
		else
			m_value /= val2.doubleValue();
	}

	/**
	* Gets the value as a String.
	* @return  Value of this object as a String.
	*/
	public String toString()
	{
		return getStringValue();
	}

	/**
	* Creates a clone of this object.
	* @return  Clone of this object.
	*/
	public Object clone()
	{
		return new DoubleType( m_value );
	}

	/**
	* Compares this DoubleType with the specified IValueType object for order,
	* based on their stored double value. Returns a negative integer, zero, or a positive integer
	* if this DoubleType is less than, equal to, or greater than the specified
	* IValueType.
	*
	* @param dt the IValueType to be compared
	* @return a negative integer, zero, or a positive integer if this DoubleType is less than, equal to, or greater than the specified IValueType.
	* @throws ClassCastException if dt is not a IValueType
	*/
	public int compareTo(Object dt)
	{
		if (!(dt instanceof IValueType))
			throw new ClassCastException("Cannot compare DoubleType with a "+dt.getClass().getName());
		double dtVal = ((IValueType)dt).getDoubleValue();
		if (m_value > dtVal)
			return 1;
		if (m_value < dtVal)
			return -1;
		return 0;
	}

	/**
	* Gets the value as a Number object.
	* @return Number object
	*/
	public Number getNumber()
	{
		return new Double(m_value);
	}


}