/* MathContext.java --
Copyright (C) 1999, 2000, 2002, 2004, 2005 Free Software Foundation, Inc.
This file is part of GNU Classpath.
GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
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General Public License for more details.
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02110-1301 USA.
Linking this library statically or dynamically with other modules is
making a combined work based on this library. Thus, the terms and
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As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
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terms of your choice, provided that you also meet, for each linked
independent module, the terms and conditions of the license of that
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package java.math;
import java.io.Serializable;
/**
* Immutable objects describing settings such as rounding mode and digit
* precision for numerical operations such as those in the BigDecimal class.
* @author Anthony Balkissoon abalkiss at redhat dot com
*
*/
public final class MathContext implements Serializable
{
/** A MathContext for unlimited precision arithmetic * */
public static final MathContext UNLIMITED =
new MathContext(0, RoundingMode.HALF_UP);
/**
* A MathContext for the IEEE 754R Decimal32 format - 7 digit preicision and
* HALF_EVEN rounding.
*/
public static final MathContext DECIMAL32 =
new MathContext(7, RoundingMode.HALF_EVEN);
/**
* A MathContext for the IEEE 754R Decimal64 format - 16 digit preicision and
* HALF_EVEN rounding.
*/
public static final MathContext DECIMAL64 =
new MathContext(16, RoundingMode.HALF_EVEN);
/**
* A MathContext for the IEEE 754R Decimal128 format - 34 digit preicision and
* HALF_EVEN rounding.
*/
public static final MathContext DECIMAL128 =
new MathContext(34, RoundingMode.HALF_EVEN);
/**
* This is the serialVersionUID reported here:
* java.sun.com/j2se/1.5.0/docs/api/serialized-form.html#java.math.MathContext
*/
private static final long serialVersionUID = 5579720004786848255L;
private int precision;
private RoundingMode roundMode;
/**
* Constructs a new MathContext with the specified precision and with HALF_UP
* rounding.
* @param setPrecision the precision for the new MathContext
*
* @throws IllegalArgumentException if precision is < 0.
*/
public MathContext(int setPrecision)
{
this(setPrecision, RoundingMode.HALF_UP);
}
/**
* Constructs a new MathContext with the specified precision and rounding
* mode.
* @param setPrecision the precision
* @param setRoundingMode the rounding mode
*
* @throws IllegalArgumentException if precision is < 0.
*/
public MathContext(int setPrecision, RoundingMode setRoundingMode)
{
if (setPrecision < 0)
throw new IllegalArgumentException("Precision cannot be less than zero.");
precision = setPrecision;
roundMode = setRoundingMode;
}
/**
* Constructs a MathContext from a String that has the same form as one
* produced by the toString() method.
* @param val
*
* @throws IllegalArgumentException if the String is not in the correct
* format or if the precision specified is < 0.
*/
public MathContext(String val)
{
try
{
int roundingModeIndex = val.indexOf("roundingMode", 10);
precision = Integer.parseInt(val.substring(10, roundingModeIndex - 1));
roundMode = RoundingMode.valueOf(val.substring(roundingModeIndex + 13));
}
catch (NumberFormatException nfe)
{
throw new IllegalArgumentException("String not in correct format");
}
catch (IllegalArgumentException iae)
{
throw new IllegalArgumentException("String not in correct format");
}
if (precision < 0)
throw new IllegalArgumentException("Precision cannot be less than 0.");
}
/**
* Returns true if x is a MathContext and has the same precision setting
* and rounding mode as this MathContext.
*
* @return true if the above conditions hold
*/
public boolean equals(Object x)
{
if (!(x instanceof MathContext))
return false;
MathContext mc = (MathContext)x;
return mc.precision == this.precision
&& mc.roundMode.equals(this.roundMode);
}
/**
* Returns the precision setting.
* @return the precision setting.
*/
public int getPrecision()
{
return precision;
}
/**
* Returns the rounding mode setting. This will be one of
* RoundingMode.CEILING, RoundingMode.DOWN, RoundingMode.FLOOR,
* RoundingMode.HALF_DOWN, RoundingMode.HALF_EVEN, RoundingMode.HALF_UP,
* RoundingMode.UNNECESSARY, or RoundingMode.UP.
* @return the rounding mode setting.
*/
public RoundingMode getRoundingMode()
{
return roundMode;
}
/**
* Returns "precision=p roundingMode=MODE" where p is an int giving the
* precision and MODE is UP, DOWN, HALF_UP, HALF_DOWN, HALF_EVEN, CEILING,
* FLOOR, or UNNECESSARY corresponding to rounding modes.
*
* @return a String describing this MathContext
*/
public String toString()
{
return "precision="+precision+" roundingMode="+roundMode;
}
/**
* Returns the hashcode for this MathContext.
* @return the hashcode for this MathContext.
*/
public int hashCode()
{
return precision ^ roundMode.hashCode();
}
}