Package org.eclipse.rdf4j.examples.function

Class ExistingPalindromeFunction

java.lang.Object

org.eclipse.rdf4j.examples.function.ExistingPalindromeFunction

All Implemented Interfaces:

Function

public class ExistingPalindromeFunction
extends Object
implements Function

An example custom SPARQL function that detects palindromes that already exist in the database.

Author:

Jeen Broekstra

Field Summary

Fields

Modifier and Type	Field	Description
static final String	NAMESPACE

Constructor Summary

Constructors

Constructor	Description
ExistingPalindromeFunction()

Method Summary

Modifier and Type	Method	Description
Value	evaluate(ValueFactory valueFactory, Value... args)	Evaluate the function over the supplied input arguments, using the supplied ValueFactory to produce the result.
Value	evaluate(TripleSource tripleSource, Value... args)	Executes the existingPalindrome function.
String	getURI()	return the URI 'http://example.org/custom-function/existingPalindrome' as a String

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

mustReturnDifferentResult

Field Details

NAMESPACE

public static final String NAMESPACE

See Also:

• Constant Field Values

Constructor Details

ExistingPalindromeFunction

public ExistingPalindromeFunction()

Method Details

getURI

public String getURI()

return the URI 'http://example.org/custom-function/existingPalindrome' as a String

Specified by:

getURI in interface Function

evaluate

public Value evaluate(TripleSource tripleSource,
 Value... args)
               throws ValueExprEvaluationException

Executes the existingPalindrome function.

Specified by:

evaluate in interface Function

Parameters:

tripleSource - the TripleSource used in the query evaluation. This can be used to access the current state of the store.

args - the function input arguments.

Returns:

A boolean literal representing true if the input argument is a palindrome and exists in the database, false otherwise.

Throws:

ValueExprEvaluationException - if more than one argument is supplied or if the supplied argument is not a literal.

evaluate

public Value 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