it.unibz.inf.ontop.model.term.functionsymbol.impl

Class RDFTermFunctionSymbolImpl

java.lang.Object

it.unibz.inf.ontop.model.term.impl.PredicateImpl

it.unibz.inf.ontop.model.term.functionsymbol.impl.FunctionSymbolImpl

it.unibz.inf.ontop.model.term.functionsymbol.impl.RDFTermFunctionSymbolImpl

All Implemented Interfaces:

FunctionSymbol, Predicate, RDFTermFunctionSymbol

public class RDFTermFunctionSymbolImpl
extends FunctionSymbolImpl
implements RDFTermFunctionSymbol

Nested Class Summary

Nested classes/interfaces inherited from interface it.unibz.inf.ontop.model.term.functionsymbol.FunctionSymbol

FunctionSymbol.FunctionalTermNullability

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	RDFTermFunctionSymbolImpl(TermType lexicalType, MetaRDFTermType typeTermType)

Method Summary

Modifier and Type	Method and Description
protected ImmutableTerm	buildTermAfterEvaluation(it.unibz.inf.ontop.com.google.common.collect.ImmutableList<ImmutableTerm> newTerms, TermFactory termFactory, VariableNullability variableNullability) By default, just build a new functional term.
boolean	canBePostProcessed(it.unibz.inf.ontop.com.google.common.collect.ImmutableList<? extends ImmutableTerm> arguments) 1.
protected boolean	canBeSafelyDecomposedIntoConjunction(it.unibz.inf.ontop.com.google.common.collect.ImmutableList<? extends ImmutableTerm> terms, VariableNullability variableNullability, it.unibz.inf.ontop.com.google.common.collect.ImmutableList<? extends ImmutableTerm> otherTerms) TODO: stop overriding (only use the top implementation)
IncrementalEvaluation	evaluateIsNotNull(it.unibz.inf.ontop.com.google.common.collect.ImmutableList<? extends ImmutableTerm> terms, TermFactory termFactory, VariableNullability variableNullability) Overridden because, it officially "tolerates" NULLs, due to the requirement that either its arguments are both null or both non-null.
IncrementalEvaluation	evaluateStrictEq(it.unibz.inf.ontop.com.google.common.collect.ImmutableList<? extends ImmutableTerm> terms, ImmutableTerm otherTerm, TermFactory termFactory, VariableNullability variableNullability) Default implementation, to be overridden to convert more cases Incoming terms are not simplified as they are presumed to be already simplified (so please simplify them before)
Optional<TermTypeInference>	inferType(it.unibz.inf.ontop.com.google.common.collect.ImmutableList<? extends ImmutableTerm> terms)
boolean	isAlwaysInjectiveInTheAbsenceOfNonInjectiveFunctionalTerms() When the function symbol is, in the absence of non-injective functional sub-terms, sometimes but not always injective, please override isInjective(...)
protected boolean	mayReturnNullWithoutNullArguments() Returns false when a functional term with this symbol: 1.
Stream<Variable>	proposeProvenanceVariables(it.unibz.inf.ontop.com.google.common.collect.ImmutableList<? extends ImmutableTerm> terms) Looks at the lexical term for provenance variables
FunctionalTermSimplification	simplifyAsGuaranteedToBeNonNull(it.unibz.inf.ontop.com.google.common.collect.ImmutableList<? extends ImmutableTerm> terms, TermFactory termFactory) Overridden because RDF(...) officially "tolerates" NULLs (so as to complain when only one argument is NULL, which should never happen)
protected boolean	tolerateNulls() E.g.

Methods inherited from class it.unibz.inf.ontop.model.term.functionsymbol.impl.FunctionSymbolImpl

analyzeInjectivity, decomposeInjectiveTopFunctionalTerm, enableIfElseNullLifting, evaluateNullability, evaluateStrictEqWithFunctionalTerm, evaluateStrictEqWithNonNullConstant, getExpectedBaseType, getExpectedBaseTypes, isAggregation, isDeterministic, isInjective, isNullable, simplify, transformIntoRegularArguments, tryToLiftMagicNumbers

Methods inherited from class it.unibz.inf.ontop.model.term.impl.PredicateImpl

equals, getArity, getName, hashCode, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface it.unibz.inf.ontop.model.term.functionsymbol.FunctionSymbol

analyzeInjectivity, evaluateNullability, getExpectedBaseType, isAggregation, isDeterministic, isNullable, simplify

Methods inherited from interface it.unibz.inf.ontop.model.term.functionsymbol.Predicate

getArity, getName

Constructor Detail

RDFTermFunctionSymbolImpl

protected RDFTermFunctionSymbolImpl(TermType lexicalType,
                                    MetaRDFTermType typeTermType)

Method Detail

isAlwaysInjectiveInTheAbsenceOfNonInjectiveFunctionalTerms

public boolean isAlwaysInjectiveInTheAbsenceOfNonInjectiveFunctionalTerms()

Description copied from class: FunctionSymbolImpl

When the function symbol is, in the absence of non-injective functional sub-terms, sometimes but not always injective, please override isInjective(...)

Specified by:

isAlwaysInjectiveInTheAbsenceOfNonInjectiveFunctionalTerms in class FunctionSymbolImpl

inferType

public Optional<TermTypeInference> inferType(it.unibz.inf.ontop.com.google.common.collect.ImmutableList<? extends ImmutableTerm> terms)

Specified by:

inferType in interface FunctionSymbol

buildTermAfterEvaluation

protected ImmutableTerm buildTermAfterEvaluation(it.unibz.inf.ontop.com.google.common.collect.ImmutableList<ImmutableTerm> newTerms,
                                                 TermFactory termFactory,
                                                 VariableNullability variableNullability)

Description copied from class: FunctionSymbolImpl

By default, just build a new functional term. NB: If the function symbol does not tolerate NULL values, no need to handle them here.

Overrides:

buildTermAfterEvaluation in class FunctionSymbolImpl

canBePostProcessed

public boolean canBePostProcessed(it.unibz.inf.ontop.com.google.common.collect.ImmutableList<? extends ImmutableTerm> arguments)

Description copied from interface: FunctionSymbol

1. When a functional term simplifies itself in a BOTTOM-UP manner: Returns true if is guaranteed to "simplify itself" as a Constant when receiving Constants as arguments (outside the optimization phase) . 2. When a functional term simplifies itself in a TOP-DOWN manner (e.g. IF-THEN-ELSE functional terms): The permission for post-processing may depend on the ability of sub-functional terms to be post-processed or safely evaluated by the DB engine. (Recall that top-down evaluation allows some arguments not to be evaluated when their pre-conditions are not met. This is particularly valuable for preventing fatal errors).

Specified by:

canBePostProcessed in interface FunctionSymbol

mayReturnNullWithoutNullArguments

protected boolean mayReturnNullWithoutNullArguments()

Description copied from class: FunctionSymbolImpl

Returns false when a functional term with this symbol: 1. never produce NULLs 2. May produce NULLs but it is always due to a NULL argument

Specified by:

mayReturnNullWithoutNullArguments in class FunctionSymbolImpl

tolerateNulls

protected boolean tolerateNulls()

E.g. RDF(NULL, IRI) is invalid and therefore does not simplify itself to NULL.

Specified by:

tolerateNulls in class FunctionSymbolImpl

evaluateStrictEq

public IncrementalEvaluation evaluateStrictEq(it.unibz.inf.ontop.com.google.common.collect.ImmutableList<? extends ImmutableTerm> terms,
                                              ImmutableTerm otherTerm,
                                              TermFactory termFactory,
                                              VariableNullability variableNullability)

Description copied from class: FunctionSymbolImpl

Default implementation, to be overridden to convert more cases Incoming terms are not simplified as they are presumed to be already simplified (so please simplify them before)

Specified by:

evaluateStrictEq in interface FunctionSymbol

Overrides:

evaluateStrictEq in class FunctionSymbolImpl

evaluateIsNotNull

public IncrementalEvaluation evaluateIsNotNull(it.unibz.inf.ontop.com.google.common.collect.ImmutableList<? extends ImmutableTerm> terms,
                                               TermFactory termFactory,
                                               VariableNullability variableNullability)

Overridden because, it officially "tolerates" NULLs, due to the requirement that either its arguments are both null or both non-null. Nevertheless, the "spirit" of the decomposition is the same.

Specified by:

evaluateIsNotNull in interface FunctionSymbol

Overrides:

evaluateIsNotNull in class FunctionSymbolImpl

proposeProvenanceVariables

public Stream<Variable> proposeProvenanceVariables(it.unibz.inf.ontop.com.google.common.collect.ImmutableList<? extends ImmutableTerm> terms)

Looks at the lexical term for provenance variables

Specified by:

proposeProvenanceVariables in interface FunctionSymbol

Overrides:

proposeProvenanceVariables in class FunctionSymbolImpl

canBeSafelyDecomposedIntoConjunction

protected boolean canBeSafelyDecomposedIntoConjunction(it.unibz.inf.ontop.com.google.common.collect.ImmutableList<? extends ImmutableTerm> terms,
                                                       VariableNullability variableNullability,
                                                       it.unibz.inf.ontop.com.google.common.collect.ImmutableList<? extends ImmutableTerm> otherTerms)

TODO: stop overriding (only use the top implementation)

Overrides:

canBeSafelyDecomposedIntoConjunction in class FunctionSymbolImpl

simplifyAsGuaranteedToBeNonNull

public FunctionalTermSimplification simplifyAsGuaranteedToBeNonNull(it.unibz.inf.ontop.com.google.common.collect.ImmutableList<? extends ImmutableTerm> terms,
                                                                    TermFactory termFactory)

Overridden because RDF(...) officially "tolerates" NULLs (so as to complain when only one argument is NULL, which should never happen)

Specified by:

simplifyAsGuaranteedToBeNonNull in interface FunctionSymbol

Overrides:

simplifyAsGuaranteedToBeNonNull in class FunctionSymbolImpl