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

Class FunctionSymbolImpl

java.lang.Object

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

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

All Implemented Interfaces:

FunctionSymbol, Predicate

Direct Known Subclasses:

AbstractAggregationFunctionSymbol, AbstractArgDependentTypedDBFunctionSymbol, AbstractCommonDenominatorFunctionSymbol, AbstractTypedDBFunctionSymbol, BinaryNumericLexicalFunctionSymbolImpl, BooleanFunctionSymbolImpl, DefaultTypedDBMathBinaryOperator, DefaultUntypedDBFunctionSymbol, DefaultUntypedDBMathBinaryOperator, LangTagFunctionSymbolImpl, ObjectStringTemplateFunctionSymbolImpl, RDFDatatypeStringFunctionSymbolImpl, RDFTermFunctionSymbolImpl, RDFTermTypeFunctionSymbolImpl, SPARQLLikeFunctionSymbolImpl, StrUUIDSPARQLFunctionSymbolImpl, UnaryLatelyTypedFunctionSymbolImpl, UUIDSPARQLFunctionSymbolImpl

public abstract class FunctionSymbolImpl
extends PredicateImpl
implements FunctionSymbol

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	FunctionSymbolImpl(String name, it.unibz.inf.ontop.com.google.common.collect.ImmutableList<TermType> expectedBaseTypes)

Method Summary

Modifier and Type	Method and Description
Optional<ImmutableFunctionalTerm.FunctionalTermDecomposition>	analyzeInjectivity(it.unibz.inf.ontop.com.google.common.collect.ImmutableList<? extends ImmutableTerm> arguments, it.unibz.inf.ontop.com.google.common.collect.ImmutableSet<Variable> nonFreeVariables, VariableNullability variableNullability, VariableGenerator variableGenerator, TermFactory termFactory) To be overridden when is sometimes but not always injective in the absence of non-injective functional terms
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.
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) ONLY for injective function symbols Makes sure that the conjunction would never evaluate as FALSE instead of NULL (first produced equality evaluated as false, while the second evaluates as NULL)
protected ImmutableFunctionalTerm.FunctionalTermDecomposition	decomposeInjectiveTopFunctionalTerm(it.unibz.inf.ontop.com.google.common.collect.ImmutableList<? extends ImmutableTerm> arguments, it.unibz.inf.ontop.com.google.common.collect.ImmutableSet<Variable> nonFreeVariables, VariableNullability variableNullability, VariableGenerator variableGenerator, TermFactory termFactory) Only when injectivity of the top function symbol is proved!
protected boolean	enableIfElseNullLifting() Returns false if IfElseNullLifting must be disabled althrough it may have been technically possible.
IncrementalEvaluation	evaluateIsNotNull(it.unibz.inf.ontop.com.google.common.collect.ImmutableList<? extends ImmutableTerm> terms, TermFactory termFactory, VariableNullability variableNullability) Default implementation, can be overridden
FunctionSymbol.FunctionalTermNullability	evaluateNullability(it.unibz.inf.ontop.com.google.common.collect.ImmutableList<? extends NonFunctionalTerm> arguments, VariableNullability childNullability, TermFactory termFactory)
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)
protected IncrementalEvaluation	evaluateStrictEqWithFunctionalTerm(it.unibz.inf.ontop.com.google.common.collect.ImmutableList<? extends ImmutableTerm> terms, ImmutableFunctionalTerm otherTerm, TermFactory termFactory, VariableNullability variableNullability) Default implementation, can be overridden
protected IncrementalEvaluation	evaluateStrictEqWithNonNullConstant(it.unibz.inf.ontop.com.google.common.collect.ImmutableList<? extends ImmutableTerm> terms, NonNullConstant otherTerm, TermFactory termFactory, VariableNullability variableNullability) Default implementation, does nothing, can be overridden
TermType	getExpectedBaseType(int index)
protected it.unibz.inf.ontop.com.google.common.collect.ImmutableList<TermType>	getExpectedBaseTypes()
boolean	isAggregation() By default, assume it is not an aggregation function symbol To be overridden when needed
protected abstract boolean	isAlwaysInjectiveInTheAbsenceOfNonInjectiveFunctionalTerms() When the function symbol is, in the absence of non-injective functional sub-terms, sometimes but not always injective, please override isInjective(...)
boolean	isDeterministic()
protected boolean	isInjective(it.unibz.inf.ontop.com.google.common.collect.ImmutableList<? extends ImmutableTerm> arguments, VariableNullability variableNullability, TermFactory termFactory)
boolean	isNullable(it.unibz.inf.ontop.com.google.common.collect.ImmutableSet<Integer> nullableIndexes) By default, to be overridden by function symbols that supports tolerate NULL values
protected abstract 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) Conservative by default Can be overridden
ImmutableTerm	simplify(it.unibz.inf.ontop.com.google.common.collect.ImmutableList<? extends ImmutableTerm> terms, TermFactory termFactory, VariableNullability variableNullability)
FunctionalTermSimplification	simplifyAsGuaranteedToBeNonNull(it.unibz.inf.ontop.com.google.common.collect.ImmutableList<? extends ImmutableTerm> terms, TermFactory termFactory) By default, only handles the case of function symbols that do not tolerate nulls and never return nulls in the absence of nulls as input.
protected abstract boolean	tolerateNulls() Returns true if is not guaranteed to return NULL when one argument is NULL.
protected it.unibz.inf.ontop.com.google.common.collect.ImmutableList<? extends ImmutableTerm>	transformIntoRegularArguments(it.unibz.inf.ontop.com.google.common.collect.ImmutableList<? extends NonFunctionalTerm> arguments, TermFactory termFactory) By default, reuses the same arguments Needed to be overridden by function symbols that require EXPRESSIONS for some of their arguments
protected Optional<ImmutableTerm>	tryToLiftMagicNumbers(it.unibz.inf.ontop.com.google.common.collect.ImmutableList<ImmutableTerm> newTerms, TermFactory termFactory, VariableNullability variableNullability, boolean isBoolean)

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

canBePostProcessed, inferType

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

getArity, getName

Constructor Detail

FunctionSymbolImpl

protected FunctionSymbolImpl(@Nonnull
                             String name,
                             @Nonnull
                             it.unibz.inf.ontop.com.google.common.collect.ImmutableList<TermType> expectedBaseTypes)

Method Detail

isAlwaysInjectiveInTheAbsenceOfNonInjectiveFunctionalTerms

protected abstract boolean isAlwaysInjectiveInTheAbsenceOfNonInjectiveFunctionalTerms()

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

evaluateNullability

public FunctionSymbol.FunctionalTermNullability evaluateNullability(it.unibz.inf.ontop.com.google.common.collect.ImmutableList<? extends NonFunctionalTerm> arguments,
                                                                    VariableNullability childNullability,
                                                                    TermFactory termFactory)

Specified by:

evaluateNullability in interface FunctionSymbol

transformIntoRegularArguments

protected it.unibz.inf.ontop.com.google.common.collect.ImmutableList<? extends ImmutableTerm> transformIntoRegularArguments(it.unibz.inf.ontop.com.google.common.collect.ImmutableList<? extends NonFunctionalTerm> arguments,
                                                                                                                            TermFactory termFactory)

By default, reuses the same arguments Needed to be overridden by function symbols that require EXPRESSIONS for some of their arguments

simplify

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

Specified by:

simplify in interface FunctionSymbol

evaluateStrictEq

public 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)

Specified by:

evaluateStrictEq in interface FunctionSymbol

evaluateIsNotNull

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

Default implementation, can be overridden

Specified by:

evaluateIsNotNull in interface FunctionSymbol

isDeterministic

public boolean isDeterministic()

Specified by:

isDeterministic in interface FunctionSymbol

isNullable

public boolean isNullable(it.unibz.inf.ontop.com.google.common.collect.ImmutableSet<Integer> nullableIndexes)

By default, to be overridden by function symbols that supports tolerate NULL values

Specified by:

isNullable in interface FunctionSymbol

isAggregation

public boolean isAggregation()

By default, assume it is not an aggregation function symbol To be overridden when needed

Specified by:

isAggregation in interface FunctionSymbol

proposeProvenanceVariables

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

Conservative by default Can be overridden

Specified by:

proposeProvenanceVariables in interface FunctionSymbol

simplifyAsGuaranteedToBeNonNull

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

By default, only handles the case of function symbols that do not tolerate nulls and never return nulls in the absence of nulls as input.

Specified by:

simplifyAsGuaranteedToBeNonNull in interface FunctionSymbol

evaluateStrictEqWithFunctionalTerm

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

Default implementation, can be overridden

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)

ONLY for injective function symbols Makes sure that the conjunction would never evaluate as FALSE instead of NULL (first produced equality evaluated as false, while the second evaluates as NULL)

evaluateStrictEqWithNonNullConstant

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

Default implementation, does nothing, can be overridden

tolerateNulls

protected abstract boolean tolerateNulls()

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.

mayReturnNullWithoutNullArguments

protected abstract boolean mayReturnNullWithoutNullArguments()

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

enableIfElseNullLifting

protected boolean enableIfElseNullLifting()

Returns false if IfElseNullLifting must be disabled althrough it may have been technically possible. False by defaults

analyzeInjectivity

public Optional<ImmutableFunctionalTerm.FunctionalTermDecomposition> analyzeInjectivity(it.unibz.inf.ontop.com.google.common.collect.ImmutableList<? extends ImmutableTerm> arguments,
                                                                                        it.unibz.inf.ontop.com.google.common.collect.ImmutableSet<Variable> nonFreeVariables,
                                                                                        VariableNullability variableNullability,
                                                                                        VariableGenerator variableGenerator,
                                                                                        TermFactory termFactory)

To be overridden when is sometimes but not always injective in the absence of non-injective functional terms

Specified by:

analyzeInjectivity in interface FunctionSymbol

decomposeInjectiveTopFunctionalTerm

protected ImmutableFunctionalTerm.FunctionalTermDecomposition decomposeInjectiveTopFunctionalTerm(it.unibz.inf.ontop.com.google.common.collect.ImmutableList<? extends ImmutableTerm> arguments,
                                                                                                  it.unibz.inf.ontop.com.google.common.collect.ImmutableSet<Variable> nonFreeVariables,
                                                                                                  VariableNullability variableNullability,
                                                                                                  VariableGenerator variableGenerator,
                                                                                                  TermFactory termFactory)

Only when injectivity of the top function symbol is proved!

isInjective

protected final boolean isInjective(it.unibz.inf.ontop.com.google.common.collect.ImmutableList<? extends ImmutableTerm> arguments,
                                    VariableNullability variableNullability,
                                    TermFactory termFactory)

buildTermAfterEvaluation

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. NB: If the function symbol does not tolerate NULL values, no need to handle them here.

getExpectedBaseTypes

protected it.unibz.inf.ontop.com.google.common.collect.ImmutableList<TermType> getExpectedBaseTypes()

getExpectedBaseType

public TermType getExpectedBaseType(int index)

Specified by:

getExpectedBaseType in interface FunctionSymbol

tryToLiftMagicNumbers

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