org.aksw.sparqlify.core.datatypes

Class SparqlFunctionImpl

java.lang.Object

org.aksw.sparqlify.core.datatypes.SparqlFunctionImpl

All Implemented Interfaces:

SparqlFunction

public class SparqlFunctionImpl
extends Object
implements SparqlFunction

Constructor Summary

Constructors

Constructor and Description
SparqlFunctionImpl(String name, MethodSignature<TypeToken> signature, SqlExprEvaluator evaluator, ExprSubstitutorSql substitutor)
SparqlFunctionImpl(String name, SqlExprEvaluator evaluator)
SparqlFunctionImpl(String name, SqlExprEvaluator evaluator, ExprSubstitutorSql substitutor)

Method Summary

Methods

Modifier and Type	Method and Description
SqlExprEvaluator	getEvaluator() An object that may evaluate the result of a SPARQL function based on its (raw) arguments (Expr objects) Used for reusing Jena's Expr.eval(...) methods.
String	getName()
MethodSignature<TypeToken>	getSignature() Sparql Functions can have a signature: object -> http://sparqlify.org/vocab/type/Object (anything) plainLiteral -> http://sparqlify.org/vocab/type/PlainLitera Note this signature refers to RDF types!!! - NOT SQL ONES! nonRdfTermObject -> http://sparqlify.org/vocab/type/NrtObject (excludes URIs, blanknodes and literals)
Collection<XMethod>	getSqlMethods() Deprecated.
ExprSubstitutorSql	getSubstitutor() A substitutor may yield a new, rewritten, expression based on the given argument types.
SqlMethodCandidate	lookup(List<TypeToken> argTypes) Deprecated.
void	setEvaluator(SqlExprEvaluator evaluator)
void	setSubstitutor(ExprSubstitutorSql substitutor)

Methods inherited from class java.lang.Object

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

Constructor Detail

SparqlFunctionImpl

public SparqlFunctionImpl(String name,
                  SqlExprEvaluator evaluator)

SparqlFunctionImpl

public SparqlFunctionImpl(String name,
                  SqlExprEvaluator evaluator,
                  ExprSubstitutorSql substitutor)

SparqlFunctionImpl

public SparqlFunctionImpl(String name,
                  MethodSignature<TypeToken> signature,
                  SqlExprEvaluator evaluator,
                  ExprSubstitutorSql substitutor)

Method Detail

getName

public String getName()

Specified by:

getName in interface SparqlFunction

Returns:

The name of the function

getEvaluator

public SqlExprEvaluator getEvaluator()

Description copied from interface: SparqlFunction

An object that may evaluate the result of a SPARQL function based on its (raw) arguments (Expr objects) Used for reusing Jena's Expr.eval(...) methods.

Specified by:

getEvaluator in interface SparqlFunction

Returns:

An object that can evaluate the function for given arguments. NULL if no evaluator exists.

setEvaluator

public void setEvaluator(SqlExprEvaluator evaluator)

getSubstitutor

public ExprSubstitutorSql getSubstitutor()

Description copied from interface: SparqlFunction

A substitutor may yield a new, rewritten, expression based on the given argument types. Used to specify transformation to SQL functions. E.g. ogc:intersects(ogc:geometry a, ogc:geometry b, dist) -> plainLiteral(ST_INTERSECTS(a, b 1000 * dist)) . If both arguments to ogc:intersects are constants, we could compute the result on the Java level (provided we registered such evaluator). . We could also register a transformation that eventually uses ST_INTERSECTS to archieve this goal. . ISSUE What is the role of the signature then? Essentially I want to be able to state, that some (SPARQL?) function is capable of converting between e.g. integer and double. This could be done with typeSystem.registerCoercion("src", "dst", new CoercionSparqlFunction(typeSystem, "myFunc")); If a function invocation (e.g. using E_Function or E_Call) cannot be evaluated, nor rewritten, it is assumed that the arguments are invalid, and a type error is raised.

Specified by:

getSubstitutor in interface SparqlFunction

Returns:

setSubstitutor

public void setSubstitutor(ExprSubstitutorSql substitutor)

getSqlMethods

@Deprecated
public Collection<XMethod> getSqlMethods()

Deprecated.

Specified by:

getSqlMethods in interface SparqlFunction

Returns:

The set of SQL methods registered for this Sparql Function. Should be consistent with an evaluator.

lookup

@Deprecated
public SqlMethodCandidate lookup(List<TypeToken> argTypes)

Deprecated.

Specified by:

lookup in interface SparqlFunction

Returns:

The SQL function registered with this SPARQL function that matches the given arguments best.

getSignature

public MethodSignature<TypeToken> getSignature()

Description copied from interface: SparqlFunction

Sparql Functions can have a signature: object -> http://sparqlify.org/vocab/type/Object (anything) plainLiteral -> http://sparqlify.org/vocab/type/PlainLitera Note this signature refers to RDF types!!! - NOT SQL ONES! nonRdfTermObject -> http://sparqlify.org/vocab/type/NrtObject (excludes URIs, blanknodes and literals)

Specified by:

getSignature in interface SparqlFunction

Returns: