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

Class RDFTermTypeFunctionSymbolImpl

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.RDFTermTypeFunctionSymbolImpl

All Implemented Interfaces:

FunctionSymbol, Predicate, RDFTermTypeFunctionSymbol

public class RDFTermTypeFunctionSymbolImpl
extends FunctionSymbolImpl
implements RDFTermTypeFunctionSymbol

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	RDFTermTypeFunctionSymbolImpl(TypeFactory typeFactory, TypeConstantDictionary dictionary, com.google.common.collect.ImmutableBiMap<DBConstant,RDFTermTypeConstant> conversionMap, boolean isSimplifiable)

Method Summary

Modifier and Type	Method and Description
protected ImmutableTerm	buildTermAfterEvaluation(com.google.common.collect.ImmutableList<ImmutableTerm> newTerms, TermFactory termFactory, VariableNullability variableNullability) By default, just build a new functional term.
boolean	canBePostProcessed(com.google.common.collect.ImmutableList<? extends ImmutableTerm> arguments) 1.
IncrementalEvaluation	evaluateIsNotNull(com.google.common.collect.ImmutableList<? extends ImmutableTerm> terms, TermFactory termFactory, VariableNullability variableNullability) Still allows the IsNotNull evaluation, even if in "not-simplifiable" mode.
protected IncrementalEvaluation	evaluateStrictEqWithNonNullConstant(com.google.common.collect.ImmutableList<? extends ImmutableTerm> terms, NonNullConstant otherTerm, TermFactory termFactory, VariableNullability variableNullability) Default implementation, does nothing, can be overridden
com.google.common.collect.ImmutableBiMap<DBConstant,RDFTermTypeConstant>	getConversionMap()
TypeConstantDictionary	getDictionary()
RDFTermTypeFunctionSymbol	getSimplifiableVariant() By default, RDFTermTypeFunctionSymbol cannot be simplified and are therefore not post-processable.
Optional<TermTypeInference>	inferType(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(...)
ImmutableFunctionalTerm	lift(com.google.common.collect.ImmutableList<? extends ImmutableTerm> terms, Function<RDFTermTypeConstant,ImmutableTerm> caseTermFct, TermFactory termFactory) Builds a DB CASE functional term with an "entry" for possible DBConstant value.
ImmutableExpression	liftExpression(com.google.common.collect.ImmutableList<? extends ImmutableTerm> terms, Function<RDFTermTypeConstant,ImmutableExpression> caseExpressionFct, TermFactory termFactory) Builds a boolean DB CASE functional term with an "entry" for possible DBConstant value.
protected boolean	mayReturnNullWithoutNullArguments() Returns false when a functional term with this symbol: 1.
protected boolean	tolerateNulls() NB: to prevent some optimization

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

analyzeInjectivity, canBeSafelyDecomposedIntoConjunction, decomposeInjectiveTopFunctionalTerm, enableIfElseNullLifting, evaluateNullability, evaluateStrictEq, evaluateStrictEqWithFunctionalTerm, 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.RDFTermTypeFunctionSymbol

lift

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

analyzeInjectivity, evaluateNullability, evaluateStrictEq, getExpectedBaseType, isAggregation, isDeterministic, isNullable, proposeProvenanceVariables, simplify, simplifyAsGuaranteedToBeNonNull

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

getArity, getName

Constructor Detail

RDFTermTypeFunctionSymbolImpl

protected RDFTermTypeFunctionSymbolImpl(TypeFactory typeFactory,
                                        TypeConstantDictionary dictionary,
                                        com.google.common.collect.ImmutableBiMap<DBConstant,RDFTermTypeConstant> conversionMap,
                                        boolean isSimplifiable)

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(com.google.common.collect.ImmutableList<? extends ImmutableTerm> terms)

Specified by:

inferType in interface FunctionSymbol

buildTermAfterEvaluation

protected ImmutableTerm buildTermAfterEvaluation(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(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

getConversionMap

public com.google.common.collect.ImmutableBiMap<DBConstant,RDFTermTypeConstant> getConversionMap()

Specified by:

getConversionMap in interface RDFTermTypeFunctionSymbol

getDictionary

public TypeConstantDictionary getDictionary()

Specified by:

getDictionary in interface RDFTermTypeFunctionSymbol

lift

public ImmutableFunctionalTerm lift(com.google.common.collect.ImmutableList<? extends ImmutableTerm> terms,
                                    Function<RDFTermTypeConstant,ImmutableTerm> caseTermFct,
                                    TermFactory termFactory)

Description copied from interface: RDFTermTypeFunctionSymbol

Builds a DB CASE functional term with an "entry" for possible DBConstant value. Returns NULL in the default case

Specified by:

lift in interface RDFTermTypeFunctionSymbol

liftExpression

public ImmutableExpression liftExpression(com.google.common.collect.ImmutableList<? extends ImmutableTerm> terms,
                                          Function<RDFTermTypeConstant,ImmutableExpression> caseExpressionFct,
                                          TermFactory termFactory)

Description copied from interface: RDFTermTypeFunctionSymbol

Builds a boolean DB CASE functional term with an "entry" for possible DBConstant value. Returns IS_TRUE(NULL) in the default case

Specified by:

liftExpression in interface RDFTermTypeFunctionSymbol

getSimplifiableVariant

public RDFTermTypeFunctionSymbol getSimplifiableVariant()

Description copied from interface: RDFTermTypeFunctionSymbol

By default, RDFTermTypeFunctionSymbol cannot be simplified and are therefore not post-processable. This is needed for lifting them above UNIONs using the standard binding lifting mechanisms. However, RDFTermTypeFunctionSymbol that arrive to the top construction node needs to replaced by "simplifiable" versions so as to be post-processed. Observe that we expect RDFTermTypeFunctionSymbol to either reach the top construction node or to be eliminated, as they cannot be delegated to the DB engine.

Specified by:

getSimplifiableVariant in interface RDFTermTypeFunctionSymbol

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

evaluateStrictEqWithNonNullConstant

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

Description copied from class: FunctionSymbolImpl

Default implementation, does nothing, can be overridden

Overrides:

evaluateStrictEqWithNonNullConstant in class FunctionSymbolImpl

tolerateNulls

protected boolean tolerateNulls()

NB: to prevent some optimization

Specified by:

tolerateNulls in class FunctionSymbolImpl

evaluateIsNotNull

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

Still allows the IsNotNull evaluation, even if in "not-simplifiable" mode. Important because the "not-simplifiable" functional term may be blocked in IS_NOT_NULL condition in a filter.

Specified by:

evaluateIsNotNull in interface FunctionSymbol

Overrides:

evaluateIsNotNull in class FunctionSymbolImpl