org.openrdf.query.algebra.evaluation.util

Class MathUtil

java.lang.Object

org.openrdf.query.algebra.evaluation.util.MathUtil

public class MathUtil
extends Object

A utility class for evaluation of mathematical expressions on RDF literals.

Author:

Jeen Broekstra

Field Summary

Fields

Modifier and Type	Field and Description
static int	DEFAULT_DECIMAL_EXPANSION_SCALE The default expansion scale used in division operations resulting in a decimal value with non-terminating decimal expansion.

Constructor Summary

Constructors

Constructor and Description
MathUtil()

Method Summary

Methods

Modifier and Type	Method and Description
static Literal	compute(Literal leftLit, Literal rightLit, MathExpr.MathOp op) Computes the result of applying the supplied math operator on the supplied left and right operand.
static int	getDecimalExpansionScale() Returns the decimal expansion scale used in division operations resulting in a decimal value with non-terminating decimal expansion.
static void	setDecimalExpansionScale(int decimalExpansionScale) Sets the decimal expansion scale used in divisions resulting in a decimal value with non-terminating decimal expansion.

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_DECIMAL_EXPANSION_SCALE

public static final int DEFAULT_DECIMAL_EXPANSION_SCALE

The default expansion scale used in division operations resulting in a decimal value with non-terminating decimal expansion. The OpenRDF default is 24 digits, a value used in various other SPARQL implementations, to make comparison between these systems easy.

See Also:

Constant Field Values

Constructor Detail

MathUtil

public MathUtil()

Method Detail

compute

public static Literal compute(Literal leftLit,
              Literal rightLit,
              MathExpr.MathOp op)
                       throws ValueExprEvaluationException

Computes the result of applying the supplied math operator on the supplied left and right operand.

Parameters:

leftLit - a numeric datatype literal

rightLit - a numeric datatype literal

op - a mathematical operator, as definied by MathExpr.MathOp.

Returns:

a numeric datatype literal containing the result of the operation. The result will be datatype according to the most specific data type the two operands have in common per the SPARQL/XPath spec.

Throws:

ValueExprEvaluationException

getDecimalExpansionScale

public static int getDecimalExpansionScale()

Returns the decimal expansion scale used in division operations resulting in a decimal value with non-terminating decimal expansion. By default, this value is set to 24.

Returns:

The decimal expansion scale.

setDecimalExpansionScale

public static void setDecimalExpansionScale(int decimalExpansionScale)

Sets the decimal expansion scale used in divisions resulting in a decimal value with non-terminating decimal expansion.

Parameters:

decimalExpansionScale - The decimal expansion scale to set. Note that a mimimum of 18 is required to stay compliant with the XPath specification of xsd:decimal operations.