org.eclipse.rdf4j.query.algebra.evaluation.function.xsd

Class CastFunction

java.lang.Object

org.eclipse.rdf4j.query.algebra.evaluation.function.xsd.CastFunction

All Implemented Interfaces:

Function

Direct Known Subclasses:

BooleanCast, DateTimeCast, DecimalCast, DoubleCast, FloatCast, IntegerCastFunction, StringCast

public abstract class CastFunction
extends Object
implements Function

Abstract superclass for Functions that cast an argument to an XML Schema datatype.

Author:

Jeen Broekstra

See Also:

XSD

Constructor Summary

Constructors

Constructor and Description
CastFunction()

Method Summary

Modifier and Type	Method and Description
protected abstract Literal	convert(ValueFactory vf, Value v) Convert the supplied value to a literal of the function output datatype.
Literal	evaluate(ValueFactory valueFactory, Value... args) Evaluate the function over the supplied input arguments, using the supplied ValueFactory to produce the result.
String	getURI()
protected abstract IRI	getXsdDatatype() Get the specific XML Schema datatype which this function returns.
protected String	getXsdName() Returns a prefixed name representation of the specific datatype that this function returns
protected abstract boolean	isValidForDatatype(String lexicalValue) Verifies that the supplied lexical value is valid for the datatype.
protected ValueExprEvaluationException	typeError(Value arg, Throwable cause) Creates a ValueExprEvaluationException that signals a type error.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.eclipse.rdf4j.query.algebra.evaluation.function.Function

evaluate

Constructor Detail

CastFunction

public CastFunction()

Method Detail

getURI

public final String getURI()

Specified by:

getURI in interface Function

evaluate

public Literal evaluate(ValueFactory valueFactory,
                        Value... args)
                 throws ValueExprEvaluationException

Description copied from interface: Function

Evaluate the function over the supplied input arguments, using the supplied ValueFactory to produce the result.

Specified by:

evaluate in interface Function

Parameters:

valueFactory - a ValueFactory to use for producing the function result.

args - the function input arguments.

Returns:

the function result value.

Throws:

ValueExprEvaluationException

convert

protected abstract Literal convert(ValueFactory vf,
                                   Value v)
                            throws ValueExprEvaluationException

Convert the supplied value to a literal of the function output datatype.

Parameters:

vf - the valueFactory to use

v - a value that is not a string-typed literal, and not a literal of the same datatype as the function output datatype.

Returns:

a literal value of the function output datatype

Throws:

ValueExprEvaluationException - if an error occurs in conversion.

getXsdDatatype

protected abstract IRI getXsdDatatype()

Get the specific XML Schema datatype which this function returns.

Returns:

an XML Schema datatype IRI

getXsdName

protected String getXsdName()

Returns a prefixed name representation of the specific datatype that this function returns

Returns:

a prefixed name, e.g. 'xsd:integer'.

isValidForDatatype

protected abstract boolean isValidForDatatype(String lexicalValue)

Verifies that the supplied lexical value is valid for the datatype.

Parameters:

lexicalValue - a lexical value

Returns:

true if the lexical value is valid for the datatype, false otherwise.

typeError

protected final ValueExprEvaluationException typeError(Value arg,
                                                       Throwable cause)

Creates a ValueExprEvaluationException that signals a type error.

Parameters:

arg - the function argument value.

cause - root cause throwable. May be null.

Returns:

a ValueExprEvaluationException with a standardized message and wrapped cause.