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package com.github.javaparser.symbolsolver.resolution.typeinference;
import com.github.javaparser.symbolsolver.resolution.typeinference.bounds.FalseBound;
import java.util.Optional;
import java.util.Set;
/**
* Bounds are defined for Inference Variables.
*
* @author Federico Tomassetti
*/
public abstract class Bound {
///
/// Creation of bounds
///
static Bound falseBound() {
return FalseBound.getInstance();
}
///
/// Satisfiability
///
/**
* A bound is satisfied by an inference variable substitution if, after applying the substitution,
* the assertion is true.
*/
public abstract boolean isSatisfied(InferenceVariableSubstitution inferenceVariableSubstitution);
///
/// Classification of bounds
///
/**
* Given a bound of the form α = T or T = α, we say T is an instantiation of α.
*
* Return empty if it is not an instantiation. Otherwise it returns the variable of which this is an
* instantiation.
*/
public Optional<Instantiation> isAnInstantiation() {
return Optional.empty();
}
boolean isAnInstantiationFor(InferenceVariable v) {
return isAnInstantiation().isPresent() && isAnInstantiation().get().getInferenceVariable().equals(v);
}
/**
* Given a bound of the form α <: T, we say T is a proper upper bound of α.
*
* Return empty if it is not a proper upper bound. Otherwise it returns the variable of which this is an
* proper upper bound.
*/
public Optional<ProperUpperBound> isProperUpperBound() {
return Optional.empty();
}
/**
* Given a bound of the form T <: α, we say T is a proper lower bound of α.
*
* Return empty if it is not a proper lower bound. Otherwise it returns the variable of which this is an
* proper lower bound.
*/
public Optional<ProperLowerBound> isProperLowerBound() {
return Optional.empty();
}
Optional<ProperLowerBound> isProperLowerBoundFor(InferenceVariable inferenceVariable) {
Optional<ProperLowerBound> partial = isProperLowerBound();
if (partial.isPresent() && partial.get().getInferenceVariable().equals(inferenceVariable)) {
return partial;
} else {
return Optional.empty();
}
}
Optional<ProperUpperBound> isProperUpperBoundFor(InferenceVariable inferenceVariable) {
Optional<ProperUpperBound> partial = isProperUpperBound();
if (partial.isPresent() && partial.get().getInferenceVariable().equals(inferenceVariable)) {
return partial;
} else {
return Optional.empty();
}
}
/**
* Other bounds relate two inference variables, or an inference variable to a type that contains inference
* variables. Such bounds, of the form S = T or S <: T, are called dependencies.
*/
public boolean isADependency() {
return false;
}
boolean isThrowsBoundOn(InferenceVariable inferenceVariable) {
return false;
}
///
/// Other methods
///
public abstract Set<InferenceVariable> usedInferenceVariables();
}
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