org.checkerframework.checker.index.upperbound

Class UpperBoundAnnotatedTypeFactory.UpperBoundQualifierHierarchy

java.lang.Object

org.checkerframework.framework.util.MultiGraphQualifierHierarchy

org.checkerframework.checker.index.upperbound.UpperBoundAnnotatedTypeFactory.UpperBoundQualifierHierarchy

All Implemented Interfaces:

QualifierHierarchy

Enclosing class:

UpperBoundAnnotatedTypeFactory

protected final class UpperBoundAnnotatedTypeFactory.UpperBoundQualifierHierarchy
extends MultiGraphQualifierHierarchy

The qualifier hierarchy for the upperbound type system. The qh is responsible for determining the relationships within the qualifiers - especially subtyping relations.

Nested Class Summary

Nested classes/interfaces inherited from class org.checkerframework.framework.util.MultiGraphQualifierHierarchy

MultiGraphQualifierHierarchy.MultiGraphFactory

Field Summary

Fields inherited from class org.checkerframework.framework.util.MultiGraphQualifierHierarchy

bottoms, polyQualifiers, supertypesDirect, supertypesTransitive, tops

Constructor Summary

Constructors

Constructor and Description
UpperBoundQualifierHierarchy(MultiGraphQualifierHierarchy.MultiGraphFactory factory) Create an UpperBoundQualifierHierarchy.

Method Summary

Modifier and Type	Method and Description
AnnotationMirror	greatestLowerBound(AnnotationMirror a1, AnnotationMirror a2) Returns the greatest lower bound for the qualifiers qualifier1 and qualifier2.
boolean	isSubtype(AnnotationMirror subAnno, AnnotationMirror superAnno) Computes subtyping as per the subtyping in the qualifier hierarchy structure unless both annotations are the same.
AnnotationMirror	leastUpperBound(AnnotationMirror a1, AnnotationMirror a2) Determines the least upper bound of a1 and a2.
int	numberOfIterationsBeforeWidening() Returns the number of iterations dataflow should perform before QualifierHierarchy.widenedUpperBound(AnnotationMirror, AnnotationMirror) is called or -1 if it should never be called.
AnnotationMirror	widenedUpperBound(AnnotationMirror newQualifier, AnnotationMirror previousQualifier) If the qualifier hierarchy has an infinite ascending chain, then the dataflow analysis might never reach a fixed point.

Methods inherited from class org.checkerframework.framework.util.MultiGraphQualifierHierarchy

addPolyRelations, findBottoms, findLub, findTops, finish, getBottomAnnotation, getBottomAnnotations, getPolymorphicAnnotation, getTopAnnotation, getTopAnnotations, isPolymorphicQualifier, isSubtype, isValid, toString, transitiveClosure

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.checkerframework.framework.type.QualifierHierarchy

assertSameSize, assertSameSize, canHaveEmptyAnnotationSet, findAnnotationInHierarchy, findAnnotationInSameHierarchy, getWidth, greatestLowerBound, greatestLowerBounds, greatestLowerBounds, greatestLowerBoundsTypeVariable, greatestLowerBoundTypeVariable, isSubtype, isSubtype, isSubtypeTypeVariable, isSubtypeTypeVariable, leastUpperBound, leastUpperBounds, leastUpperBounds, leastUpperBoundsTypeVariable, leastUpperBoundTypeVariable, updateMappingToMutableSet

Constructor Detail

UpperBoundQualifierHierarchy

public UpperBoundQualifierHierarchy(MultiGraphQualifierHierarchy.MultiGraphFactory factory)

Create an UpperBoundQualifierHierarchy.

Parameters:

factory - the MultiGraphFactory to use to construct this

Method Detail

greatestLowerBound

public AnnotationMirror greatestLowerBound(AnnotationMirror a1,
                                           AnnotationMirror a2)

Description copied from interface: QualifierHierarchy

Returns the greatest lower bound for the qualifiers qualifier1 and qualifier2. Returns null if the qualifiers are not from the same qualifier hierarchy.

Specified by:

greatestLowerBound in interface QualifierHierarchy

Overrides:

greatestLowerBound in class MultiGraphQualifierHierarchy

Parameters:

a1 - first qualifier

a2 - second qualifier

Returns:

greatest lower bound of the two annotations or null if the two annotations are not from the same hierarchy

leastUpperBound

public AnnotationMirror leastUpperBound(AnnotationMirror a1,
                                        AnnotationMirror a2)

Determines the least upper bound of a1 and a2. If a1 and a2 are both the same type of Value annotation, then the LUB is the result of taking the intersection of values from both a1 and a2.

Specified by:

leastUpperBound in interface QualifierHierarchy

Overrides:

leastUpperBound in class MultiGraphQualifierHierarchy

Parameters:

a1 - the first qualifier; may not be in the same hierarchy as qualifier2

a2 - the second qualifier; may not be in the same hierarchy as qualifier1

Returns:

the least upper bound of a1 and a2

widenedUpperBound

public AnnotationMirror widenedUpperBound(AnnotationMirror newQualifier,
                                          AnnotationMirror previousQualifier)

Description copied from interface: QualifierHierarchy

If the qualifier hierarchy has an infinite ascending chain, then the dataflow analysis might never reach a fixed point. To prevent this, implement this method such that it returns an upper bound for the two qualifiers that is a strict super type of the least upper bound. If this method is implemented, also override QualifierHierarchy.numberOfIterationsBeforeWidening() to return a positive number.

newQualifier is newest qualifier dataflow computed for some expression and previousQualifier is the qualifier dataflow computed on the last iteration.

If the qualifier hierarchy has no infinite ascending chain, returns the least upper bound of the two annotations.

Parameters:

newQualifier - new qualifier dataflow computed for some expression; must be in the same hierarchy as previousQualifier

previousQualifier - the previous qualifier dataflow computed on the last iteration; must be in the same hierarchy as previousQualifier

Returns:

an upper bound that is higher than the least upper bound of newQualifier and previousQualifier (or the lub if the qualifier hierarchy does not require this)

numberOfIterationsBeforeWidening

public int numberOfIterationsBeforeWidening()

Description copied from interface: QualifierHierarchy

Returns the number of iterations dataflow should perform before QualifierHierarchy.widenedUpperBound(AnnotationMirror, AnnotationMirror) is called or -1 if it should never be called.

Returns:

the number of iterations dataflow should perform before QualifierHierarchy.widenedUpperBound(AnnotationMirror, AnnotationMirror) is called or -1 if it should never be called.

isSubtype

public boolean isSubtype(AnnotationMirror subAnno,
                         AnnotationMirror superAnno)

Computes subtyping as per the subtyping in the qualifier hierarchy structure unless both annotations are the same. In this case, rhs is a subtype of lhs iff rhs contains at least every element of lhs.

Specified by:

isSubtype in interface QualifierHierarchy

Overrides:

isSubtype in class MultiGraphQualifierHierarchy

Parameters:

subAnno - the sub qualifier

superAnno - the super qualifier

Returns:

true if rhs is a subtype of lhs, false otherwise