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

Class UnaryLatelyTypedFunctionSymbolImpl

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.UnaryLatelyTypedFunctionSymbolImpl

All Implemented Interfaces:

FunctionSymbol, Predicate

Direct Known Subclasses:

UnaryLexicalFunctionSymbolImpl

public class UnaryLatelyTypedFunctionSymbolImpl
extends FunctionSymbolImpl

This function symbol takes a lexical term and a meta RDF term type term as input. Once the concrete RDF term type is determined, looks for its closest DB type and then selects the corresponding DB function symbol to use (let's call it f). Then the lexical term (l) is transformed into a natural one (n). By default, returns f(n) but further transformations can be applied over it. TODO: find a better name for it

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	UnaryLatelyTypedFunctionSymbolImpl(DBTermType dbStringType, MetaRDFTermType metaRDFTermType, DBTermType targetType, Function<DBTermType,DBFunctionSymbol> dbFunctionSymbolFct)

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.
Optional<TermTypeInference>	inferType(it.unibz.inf.ontop.com.google.common.collect.ImmutableList<? extends ImmutableTerm> terms) Could be inferred after simplification
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.
protected boolean	tolerateNulls() Returns true if is not guaranteed to return NULL when one argument is NULL.
protected ImmutableTerm	transformNaturalDBTerm(ImmutableFunctionalTerm dbTerm, DBTermType inputDBType, RDFTermType rdfType, TermFactory termFactory) By default, returns the natural DB term

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

analyzeInjectivity, canBeSafelyDecomposedIntoConjunction, decomposeInjectiveTopFunctionalTerm, enableIfElseNullLifting, evaluateIsNotNull, evaluateNullability, evaluateStrictEq, evaluateStrictEqWithFunctionalTerm, evaluateStrictEqWithNonNullConstant, getExpectedBaseType, getExpectedBaseTypes, isAggregation, isDeterministic, isInjective, isNullable, proposeProvenanceVariables, simplify, simplifyAsGuaranteedToBeNonNull, 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.Predicate

getArity, getName

Constructor Detail

UnaryLatelyTypedFunctionSymbolImpl

protected UnaryLatelyTypedFunctionSymbolImpl(DBTermType dbStringType,
                                             MetaRDFTermType metaRDFTermType,
                                             DBTermType targetType,
                                             Function<DBTermType,DBFunctionSymbol> dbFunctionSymbolFct)

Method Detail

tolerateNulls

protected boolean tolerateNulls()

Description copied from class: FunctionSymbolImpl

Returns true if is not guaranteed to return NULL when one argument is NULL. Can be the case for some function symbols that are rejecting certain cases and therefore refuse to simplify themselves, e.g. RDF(NULL,IRI) is invalid and therefore cannot be simplified.

Specified by:

tolerateNulls in class FunctionSymbolImpl

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

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)

Could be inferred after simplification

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).

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

transformNaturalDBTerm

protected ImmutableTerm transformNaturalDBTerm(ImmutableFunctionalTerm dbTerm,
                                               DBTermType inputDBType,
                                               RDFTermType rdfType,
                                               TermFactory termFactory)

By default, returns the natural DB term