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

Class AbstractOrNullFunctionSymbol

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.db.impl.DBBooleanFunctionSymbolImpl

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

All Implemented Interfaces:

BooleanFunctionSymbol, DBBooleanFunctionSymbol, DBFunctionSymbol, DBFunctionSymbolSerializer, FunctionSymbol, Predicate

Direct Known Subclasses:

FalseOrNullFunctionSymbolImpl, TrueOrNullFunctionSymbolImpl

public abstract class AbstractOrNullFunctionSymbol
extends DBBooleanFunctionSymbolImpl

Implementing the ternary logic for situations like: * NULL AND y AND ... --> FalseOrNull * NULL OR y OR ... ---> TrueOrNull N-ary (at least 1)

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	AbstractOrNullFunctionSymbol(String name, int arity, DBTermType dbBooleanTermType, boolean possibleBoolean)

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.
ImmutableTerm	simplify2VL(com.google.common.collect.ImmutableList<? extends ImmutableTerm> terms, TermFactory termFactory, VariableNullability variableNullability) 2VL: the NULL is considered "equivalent" to FALSE
protected boolean	tolerateNulls() Returns true if is not guaranteed to return NULL when one argument is NULL.
protected com.google.common.collect.ImmutableList<? extends ImmutableTerm>	transformIntoRegularArguments(com.google.common.collect.ImmutableList<? extends NonFunctionalTerm> arguments, TermFactory termFactory) Requires its arguments to be expressions

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

inBrackets, isPreferringToBePostProcessedOverBeingBlocked

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, 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.FunctionSymbol

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

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

getArity, getName

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

getNativeDBString

Constructor Detail

AbstractOrNullFunctionSymbol

protected AbstractOrNullFunctionSymbol(@Nonnull
                                       String name,
                                       int arity,
                                       DBTermType dbBooleanTermType,
                                       boolean possibleBoolean)

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.

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

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

Overrides:

mayReturnNullWithoutNullArguments in class DBBooleanFunctionSymbolImpl

simplify2VL

public ImmutableTerm simplify2VL(com.google.common.collect.ImmutableList<? extends ImmutableTerm> terms,
                                 TermFactory termFactory,
                                 VariableNullability variableNullability)

2VL: the NULL is considered "equivalent" to FALSE

transformIntoRegularArguments

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

Requires its arguments to be expressions

Overrides:

transformIntoRegularArguments in class FunctionSymbolImpl