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

Class DefaultUntypedDBMathBinaryOperator

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.db.impl.DefaultUntypedDBMathBinaryOperator

All Implemented Interfaces:

DBFunctionSymbol, DBFunctionSymbolSerializer, DBMathBinaryOperator, FunctionSymbol, Predicate

public class DefaultUntypedDBMathBinaryOperator
extends FunctionSymbolImpl
implements DBMathBinaryOperator

Mostly for the native query parser (for source queries in the mapping), which is not able to infer the type of its input. Ideally, these operators should be replaced by typed ones later on in the mapping process, once the input type can be inferred.

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	DefaultUntypedDBMathBinaryOperator(String operatorString, DBTermType rootDBTermType)

Method Summary

Modifier and Type	Method and Description
boolean	canBePostProcessed(com.google.common.collect.ImmutableList<? extends ImmutableTerm> arguments) 1.
String	getNativeDBString(com.google.common.collect.ImmutableList<? extends ImmutableTerm> terms, Function<ImmutableTerm,String> termConverter, TermFactory termFactory) Returns a String in the native query language.
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(...)
boolean	isPreferringToBePostProcessedOverBeingBlocked() By default, to be overridden when necessary
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.

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

analyzeInjectivity, buildTermAfterEvaluation, 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

clone, equals, getArity, getName, hashCode, toString

Methods inherited from class java.lang.Object

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

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

analyzeInjectivity, evaluateIsNotNull, 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

DefaultUntypedDBMathBinaryOperator

protected DefaultUntypedDBMathBinaryOperator(String operatorString,
                                             DBTermType rootDBTermType)

Method Detail

getNativeDBString

public String getNativeDBString(com.google.common.collect.ImmutableList<? extends ImmutableTerm> terms,
                                Function<ImmutableTerm,String> termConverter,
                                TermFactory termFactory)

Description copied from interface: DBFunctionSymbolSerializer

Returns a String in the native query language.

Specified by:

getNativeDBString in interface DBFunctionSymbolSerializer

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

Specified by:

inferType in interface FunctionSymbol

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

isPreferringToBePostProcessedOverBeingBlocked

public boolean isPreferringToBePostProcessedOverBeingBlocked()

By default, to be overridden when necessary

Specified by:

isPreferringToBePostProcessedOverBeingBlocked in interface DBFunctionSymbol