org.codehaus.groovy.runtime.typehandling
Class NumberMath

java.lang.Object
  org.codehaus.groovy.runtime.typehandling.NumberMath

Direct Known Subclasses:

BigDecimalMath, BigIntegerMath, FloatingPointMath, IntegerMath, LongMath

public abstract class NumberMath
extends Object

Stateless objects used to perform math on the various Number subclasses. Instances are required so that polymorphic calls work properly, but each subclass creates a singleton instance to minimize garbage. All methods must be thread-safe. The design goals of this class are as follows:

1. Support a 'least surprising' math model to scripting language users. This means that exact, or decimal math should be used for default calculations. This scheme assumes that by default, groovy literals with decimal points are instantiated as BigDecimal objects rather than binary floating points (Float, Double).
2. Do not force the appearance of exactness on a number that is by definition not guaranteed to be exact. In particular this means that if an operand in a NumberMath operation is a binary floating point number, ensure that the result remains a binary floating point number (i.e. never automatically promote a binary floating point number to a BigDecimal). This has the effect of preserving the expectations of binary floating point users and helps performance.
3. Provide an implementation that is as close as practical to the Java 1.5 BigDecimal math model which implements precision based floating point decimal math (ANSI X3.274-1996 and ANSI X3.274-1996/AM 1-2000 (section 7.4).

Author:

Steve Goetze

Constructor Summary

NumberMath()

Method Summary

static Number	abs(Number number)
protected abstract Number	absImpl(Number number)
static Number	add(Number left, Number right)
abstract Number	addImpl(Number left, Number right)
static Number	and(Number left, Number right)
protected Number	andImpl(Number left, Number right)
static int	compareTo(Number left, Number right)
abstract int	compareToImpl(Number left, Number right)
protected UnsupportedOperationException	createUnsupportedException(String operation, Number left)
static Number	divide(Number left, Number right)
abstract Number	divideImpl(Number left, Number right)
static NumberMath	getMath(Number left, Number right) Determine which NumberMath instance to use, given the supplied operands.
static Number	intdiv(Number left, Number right)
protected Number	intdivImpl(Number left, Number right)
static boolean	isBigDecimal(Number number)
static boolean	isBigInteger(Number number)
static boolean	isFloatingPoint(Number number)
static boolean	isInteger(Number number)
static boolean	isLong(Number number)
static Number	leftShift(Number left, Number right) For this operation, consider the operands independently.
protected Number	leftShiftImpl(Number left, Number right)
static Number	mod(Number left, Number right)
protected Number	modImpl(Number left, Number right)
static Number	multiply(Number left, Number right)
abstract Number	multiplyImpl(Number left, Number right)
static Number	or(Number left, Number right)
protected Number	orImpl(Number left, Number right)
static Number	rightShift(Number left, Number right) For this operation, consider the operands independently.
protected Number	rightShiftImpl(Number left, Number right)
static Number	rightShiftUnsigned(Number left, Number right) For this operation, consider the operands independently.
protected Number	rightShiftUnsignedImpl(Number left, Number right)
static Number	subtract(Number left, Number right)
abstract Number	subtractImpl(Number left, Number right)
static BigDecimal	toBigDecimal(Number n)
static BigInteger	toBigInteger(Number n)
static Number	unaryMinus(Number left)
protected abstract Number	unaryMinusImpl(Number left)
static Number	xor(Number left, Number right)
protected Number	xorImpl(Number left, Number right)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

NumberMath

public NumberMath()

Method Detail

abs

public static Number abs(Number number)

add

public static Number add(Number left,
                         Number right)

subtract

public static Number subtract(Number left,
                              Number right)

multiply

public static Number multiply(Number left,
                              Number right)

divide

public static Number divide(Number left,
                            Number right)

compareTo

public static int compareTo(Number left,
                            Number right)

or

public static Number or(Number left,
                        Number right)

and

public static Number and(Number left,
                         Number right)

xor

public static Number xor(Number left,
                         Number right)

intdiv

public static Number intdiv(Number left,
                            Number right)

mod

public static Number mod(Number left,
                         Number right)

leftShift

public static Number leftShift(Number left,
                               Number right)

For this operation, consider the operands independently. Throw an exception if the right operand (shift distance) is not an integral type. For the left operand (shift value) also require an integral type, but do NOT promote from Integer to Long. This is consistent with Java, and makes sense for the shift operators.

rightShift

public static Number rightShift(Number left,
                                Number right)

For this operation, consider the operands independently. Throw an exception if the right operand (shift distance) is not an integral type. For the left operand (shift value) also require an integral type, but do NOT promote from Integer to Long. This is consistent with Java, and makes sense for the shift operators.

rightShiftUnsigned

public static Number rightShiftUnsigned(Number left,
                                        Number right)

For this operation, consider the operands independently. Throw an exception if the right operand (shift distance) is not an integral type. For the left operand (shift value) also require an integral type, but do NOT promote from Integer to Long. This is consistent with Java, and makes sense for the shift operators.

unaryMinus

public static Number unaryMinus(Number left)

isFloatingPoint

public static boolean isFloatingPoint(Number number)

isInteger

public static boolean isInteger(Number number)

isLong

public static boolean isLong(Number number)

isBigDecimal

public static boolean isBigDecimal(Number number)

isBigInteger

public static boolean isBigInteger(Number number)

toBigDecimal

public static BigDecimal toBigDecimal(Number n)

toBigInteger

public static BigInteger toBigInteger(Number n)

getMath

public static NumberMath getMath(Number left,
                                 Number right)

Determine which NumberMath instance to use, given the supplied operands. This method implements the type promotion rules discussed in the documentation. Note that by the time this method is called, any Byte, Character or Short operands will have been promoted to Integer. For reference, here is the promotion matrix: bD bI D F L I bD bD bD D D bD bD bI bD bI D D bI bI D D D D D D D F D D D D D D L bD bI D D L L I bD bI D D L I Note that for division, if either operand isFloatingPoint, the result will be floating. Otherwise, the result is BigDecimal

absImpl

protected abstract Number absImpl(Number number)

addImpl

public abstract Number addImpl(Number left,
                               Number right)

subtractImpl

public abstract Number subtractImpl(Number left,
                                    Number right)

multiplyImpl

public abstract Number multiplyImpl(Number left,
                                    Number right)

divideImpl

public abstract Number divideImpl(Number left,
                                  Number right)

compareToImpl

public abstract int compareToImpl(Number left,
                                  Number right)

unaryMinusImpl

protected abstract Number unaryMinusImpl(Number left)

orImpl

protected Number orImpl(Number left,
                        Number right)

andImpl

protected Number andImpl(Number left,
                         Number right)

xorImpl

protected Number xorImpl(Number left,
                         Number right)

modImpl

protected Number modImpl(Number left,
                         Number right)

intdivImpl

protected Number intdivImpl(Number left,
                            Number right)

leftShiftImpl

protected Number leftShiftImpl(Number left,
                               Number right)

rightShiftImpl

protected Number rightShiftImpl(Number left,
                                Number right)

rightShiftUnsignedImpl

protected Number rightShiftUnsignedImpl(Number left,
                                        Number right)

createUnsupportedException

protected UnsupportedOperationException createUnsupportedException(String operation,
                                                                   Number left)