org.openrdf.query.algebra.evaluation.util
Class QueryEvaluationUtil

java.lang.Object
  org.openrdf.query.algebra.evaluation.util.QueryEvaluationUtil

public class QueryEvaluationUtil
extends Object

Author:

Arjohn Kampman

Constructor Summary

QueryEvaluationUtil()

Method Summary

static boolean	compare(Value leftVal, Value rightVal, Compare.CompareOp operator)
static boolean	compareLiterals(Literal leftLit, Literal rightLit, Compare.CompareOp operator)
static boolean	getEffectiveBooleanValue(Value value) Determines the effective boolean value (EBV) of the supplied value as defined in the SPARQL specification: The EBV of any literal whose type is xsd:boolean or numeric is false if the lexical form is not valid for that datatype (e.g.
static boolean	isSimpleLiteral(Literal l) Checks whether the supplied literal is a "simple literal" as defined in the SPARQL spec.
static boolean	isSimpleLiteral(Value v) Checks whether the supplied value is a "simple literal" as defined in the SPARQL spec.
static boolean	isStringLiteral(Literal l) Checks whether the supplied literal is a "string literal".

Methods inherited from class java.lang.Object

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

Constructor Detail

QueryEvaluationUtil

public QueryEvaluationUtil()

Method Detail

getEffectiveBooleanValue

public static boolean getEffectiveBooleanValue(Value value)
                                        throws ValueExprEvaluationException

Determines the effective boolean value (EBV) of the supplied value as defined in the SPARQL specification:

• The EBV of any literal whose type is xsd:boolean or numeric is false if the lexical form is not valid for that datatype (e.g. "abc"^^xsd:integer).
• If the argument is a typed literal with a datatype of xsd:boolean, the EBV is the value of that argument.
• If the argument is a plain literal or a typed literal with a datatype of xsd:string, the EBV is false if the operand value has zero length; otherwise the EBV is true.
• If the argument is a numeric type or a typed literal with a datatype derived from a numeric type, the EBV is false if the operand value is NaN or is numerically equal to zero; otherwise the EBV is true.
• All other arguments, including unbound arguments, produce a type error.

Parameters:

value - Some value.

Returns:

The EBV of value.

Throws:

ValueExprEvaluationException - In case the application of the EBV algorithm results in a type error.

compare

public static boolean compare(Value leftVal,
                              Value rightVal,
                              Compare.CompareOp operator)
                       throws ValueExprEvaluationException

Throws:

ValueExprEvaluationException

compareLiterals

public static boolean compareLiterals(Literal leftLit,
                                      Literal rightLit,
                                      Compare.CompareOp operator)
                               throws ValueExprEvaluationException

Throws:

ValueExprEvaluationException

isSimpleLiteral

public static boolean isSimpleLiteral(Value v)

Checks whether the supplied value is a "simple literal" as defined in the SPARQL spec. A "simple literal" is a literal without a language tag or a datatype.

isSimpleLiteral

public static boolean isSimpleLiteral(Literal l)

Checks whether the supplied literal is a "simple literal" as defined in the SPARQL spec. A "simple literal" is a literal without a language tag or a datatype.

isStringLiteral

public static boolean isStringLiteral(Literal l)

Checks whether the supplied literal is a "string literal". A "string literal" is either a simple literal or a literal with datatype xsd:string.