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

Class LexicalEBVFunctionSymbolImpl

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.BooleanFunctionSymbolImpl

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

All Implemented Interfaces:

BooleanFunctionSymbol, FunctionSymbol, Predicate

public class LexicalEBVFunctionSymbolImpl
extends BooleanFunctionSymbolImpl

https://www.w3.org/TR/sparql11-query/#ebv Limitation: - We don't look for invalid lexical form for booleans and numerics

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	LexicalEBVFunctionSymbolImpl(DBTermType dbStringType, MetaRDFTermType metaRDFTermType, DBTermType dbBooleanTermType)

Method Summary

Modifier and Type	Method and Description
boolean	blocksNegation() Returns TRUE if the NOT operator has to stay ABOVE the expression (i.e.
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.
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.
ImmutableExpression	negate(com.google.common.collect.ImmutableList<? extends ImmutableTerm> subTerms, TermFactory termFactory) Usually NOT supported when the function symbol blocks negation.
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.BooleanFunctionSymbolImpl

enableIfElseNullLifting, inferType, tryToLiftIfThenTerm, tryToLiftMagicNumbers

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

analyzeInjectivity, canBeSafelyDecomposedIntoConjunction, decomposeInjectiveTopFunctionalTerm, 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.BooleanFunctionSymbol

simplify2VL

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

LexicalEBVFunctionSymbolImpl

protected LexicalEBVFunctionSymbolImpl(DBTermType dbStringType,
                                       MetaRDFTermType metaRDFTermType,
                                       DBTermType dbBooleanTermType)

Method Detail

blocksNegation

public boolean blocksNegation()

Description copied from interface: BooleanFunctionSymbol

Returns TRUE if the NOT operator has to stay ABOVE the expression (i.e. cannot lead to a change in the operator or cannot be delegated to sub-expressions)

negate

public ImmutableExpression negate(com.google.common.collect.ImmutableList<? extends ImmutableTerm> subTerms,
                                  TermFactory termFactory)

Description copied from interface: BooleanFunctionSymbol

Usually NOT supported when the function symbol blocks negation. Please use ImmutableExpression.negate() instead.

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

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).

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 BooleanFunctionSymbolImpl