org.eclipse.rdf4j.query.algebra.evaluation.util

Class QueryEvaluationUtil

java.lang.Object

org.eclipse.rdf4j.query.algebra.evaluation.util.QueryEvaluationUtil

public class QueryEvaluationUtil
extends Object

Author:

Arjohn Kampman

Constructor Summary

Constructors

Constructor and Description
QueryEvaluationUtil()

Method Summary

Modifier and Type	Method and Description
static boolean	compare(Value leftVal, Value rightVal, Compare.CompareOp operator)
static boolean	compare(Value leftVal, Value rightVal, Compare.CompareOp operator, boolean strict)
static boolean	compareLiterals(Literal leftLit, Literal rightLit, Compare.CompareOp operator) Compares the supplied Literal arguments using the supplied operator, using strict (minimally-conforming) SPARQL 1.1 operator behavior.
static boolean	compareLiterals(Literal leftLit, Literal rightLit, Compare.CompareOp operator, boolean strict) Compares the supplied Literal arguments using the supplied operator.
static boolean	compatibleArguments(Literal arg1, Literal arg2) Checks whether the supplied two literal arguments are 'argument compatible' according to the SPARQL definition.
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	isPlainLiteral(Literal l)
static boolean	isPlainLiteral(Value v) Checks whether the supplied value is a "plain literal".
static boolean	isSimpleLiteral(Literal l) Checks whether the supplied literal is a "simple literal".
static boolean	isSimpleLiteral(Value v) Checks whether the supplied value is a "simple literal".
static boolean	isStringLiteral(Literal l) Checks whether the supplied literal is a "string literal".
static boolean	isStringLiteral(Value v) 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

compare

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

Throws:

ValueExprEvaluationException

compareLiterals

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

Compares the supplied Literal arguments using the supplied operator, using strict (minimally-conforming) SPARQL 1.1 operator behavior.

Parameters:

leftLit - the left literal argument of the comparison.

rightLit - the right literal argument of the comparison.

operator - the comparison operator to use.

Returns:

true if execution of the supplied operator on the supplied arguments succeeds, false otherwise.

Throws:

ValueExprEvaluationException - if a type error occurred.

compareLiterals

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

Compares the supplied Literal arguments using the supplied operator.

Parameters:

leftLit - the left literal argument of the comparison.

rightLit - the right literal argument of the comparison.

operator - the comparison operator to use.

strict - boolean indicating whether comparison should use strict (minimally-conforming) SPARQL 1.1 operator behavior, or extended behavior.

Returns:

true if execution of the supplied operator on the supplied arguments succeeds, false otherwise.

Throws:

ValueExprEvaluationException - if a type error occurred.

isPlainLiteral

public static boolean isPlainLiteral(Value v)

Checks whether the supplied value is a "plain literal". A "plain literal" is a literal with no datatype and optionally a language tag.

See Also:

RDF Literal Documentation

isPlainLiteral

public static boolean isPlainLiteral(Literal l)

isSimpleLiteral

public static boolean isSimpleLiteral(Value v)

Checks whether the supplied value is a "simple literal". A "simple literal" is a literal with no language tag nor datatype.

See Also:

SPARQL Simple Literal Documentation

isSimpleLiteral

public static boolean isSimpleLiteral(Literal l)

Checks whether the supplied literal is a "simple literal". A "simple literal" is a literal with no language tag and the datatype XSD.STRING.

See Also:

SPARQL Simple Literal Documentation

isStringLiteral

public static boolean isStringLiteral(Value v)

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

See Also:

SPARQL Functions on Strings Documentation

compatibleArguments

public static boolean compatibleArguments(Literal arg1,
                                          Literal arg2)

Checks whether the supplied two literal arguments are 'argument compatible' according to the SPARQL definition.

Parameters:

arg1 - the first argument

arg2 - the second argument

Returns:

true iff the two supplied arguments are argument compatible, false otherwise

See Also:

SPARQL Argument Compatibility Rules

isStringLiteral

public static boolean isStringLiteral(Literal l)

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

See Also:

SPARQL Functions on Strings Documentation