CFAbstractValue (checker-framework 3.20.0 API)

java.lang.Object
- org.checkerframework.framework.flow.CFAbstractValue<V>

All Implemented Interfaces:

AbstractValue<V>

Direct Known Subclasses:

CFValue, KeyForValue, NullnessValue
```
public abstract class CFAbstractValue<V extends CFAbstractValue<V>>
extends Object
implements AbstractValue<V>
```
An implementation of an abstract value used by the Checker Framework org.checkerframework.dataflow analysis.
A value holds a set of annotations and a type mirror. The set of annotations represents the primary annotation on a type; therefore, the set of annotations must have an annotation for each hierarchy unless the type mirror is a type variable or a wildcard that extends a type variable. Both type variables and wildcards may be missing a primary annotation. For this set of annotations, there is an additional constraint that only wildcards that extend type variables can be missing annotations.
In order to compute leastUpperBound(CFAbstractValue) and mostSpecific(CFAbstractValue, CFAbstractValue), the case where one value has an annotation in a hierarchy and the other does not must be handled. For type variables, the AnnotatedTypeMirror.AnnotatedTypeVariable for the declaration of the type variable is used. The AnnotatedTypeMirror.AnnotatedTypeVariable is computed using the type mirror. For wildcards, it is not always possible to get the AnnotatedTypeMirror.AnnotatedWildcardType for the type mirror. However, a CFAbstractValue's type mirror is only a wildcard if the type of some expression is a wildcard. The type of an expression is only a wildcard because the Checker Framework does not implement capture conversion. For these uses of uncaptured wildcards, only the primary annotation on the upper bound is ever used. So, the set of annotations represents the primary annotation on the wildcard's upper bound. If that upper bound is a type variable, then the set of annotations could be missing an annotation in a hierarchy.

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`protected class`	`CFAbstractValue.AnnotationSetCombiner` Combines two sets of AnnotationMirrors by hierarchy.
`protected class`	`CFAbstractValue.ValueGlb` Computes the GLB of two sets of annotations.
`protected class`	`CFAbstractValue.ValueLub` Computes the least upper bound or, if `shouldWiden` is true, an upper bounds of two sets of annotations.

Field Summary

Fields
Modifier and Type	Field and Description
`protected CFAbstractAnalysis<V,?,?>`	`analysis` The analysis class this value belongs to.
`protected Set<AnnotationMirror>`	`annotations` The annotations in this abstract value.
`protected TypeMirror`	`underlyingType` The underlying (Java) type in this abstract value.

Constructor Summary

Constructors
Modifier	Constructor and Description
`protected`	`CFAbstractValue(CFAbstractAnalysis<V,?,?> analysis, Set<AnnotationMirror> annotations, TypeMirror underlyingType)` Creates a new CFAbstractValue.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`boolean`	`canBeMissingAnnotations()` Returns whether or not the set of annotations can be missing an annotation for any hierarchy.
`boolean`	`equals(@Nullable Object obj)`
`Set<AnnotationMirror>`	`getAnnotations()` Returns a set of annotations.
`TypeMirror`	`getUnderlyingType()`
`V`	`greatestLowerBound(V other)` Compute the greatest lower bound of two values.
`int`	`hashCode()`
`V`	`leastUpperBound(V other)` Compute the least upper bound of two values.
`V`	`mostSpecific(V other, V backup)` Returns the more specific version of two values `this` and `other`.
`String`	`toString()` Returns the string representation.
`String`	`toStringFullyQualified()` Returns the string representation, using fully-qualified names.
`String`	`toStringSimple()` Returns the string representation, using simple (not fully-qualified) names.
`static boolean`	`validateSet(Set<AnnotationMirror> annos, TypeMirror typeMirror, QualifierHierarchy hierarchy)` Returns true if the set has an annotation from every hierarchy (or if it doesn't need to); returns false if the set is missing an annotation from some hierarchy.
`V`	`widenUpperBound(V previous)` Compute an upper bound of two values that is wider than the least upper bound of the two values.

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

- Field Detail
  - analysis
```
protected final CFAbstractAnalysis<V extends CFAbstractValue<V>,?,?> analysis
```
    The analysis class this value belongs to.
  - underlyingType
```
protected final TypeMirror underlyingType
```
    The underlying (Java) type in this abstract value.
  - annotations
```
protected final Set<AnnotationMirror> annotations
```
    The annotations in this abstract value.
- Constructor Detail
  - CFAbstractValue
```
protected CFAbstractValue(CFAbstractAnalysis<V,?,?> analysis,
                          Set<AnnotationMirror> annotations,
                          TypeMirror underlyingType)
```
    Creates a new CFAbstractValue.
    
    Parameters:
    
    analysis - the analysis class this value belongs to
    
    annotations - the annotations in this abstract value
    
    underlyingType - the underlying (Java) type in this abstract value
- Method Detail
  - validateSet
```
public static boolean validateSet(Set<AnnotationMirror> annos,
                                  TypeMirror typeMirror,
                                  QualifierHierarchy hierarchy)
```
    Returns true if the set has an annotation from every hierarchy (or if it doesn't need to); returns false if the set is missing an annotation from some hierarchy.
    
    Parameters:
    
    annos - set of annotations
    
    typeMirror - where the annotations are written
    
    hierarchy - the qualifier hierarchy
    
    Returns:
    
    true if no annotations are missing
  - canBeMissingAnnotations
```
public boolean canBeMissingAnnotations()
```
    Returns whether or not the set of annotations can be missing an annotation for any hierarchy.
    
    Returns:
    
    whether or not the set of annotations can be missing an annotation
  - getAnnotations
```
@Pure
public Set<AnnotationMirror> getAnnotations()
```
    Returns a set of annotations. If canBeMissingAnnotations() returns true, then the set of annotations may not have an annotation for every hierarchy.
    To get the single annotation in a particular hierarchy, use QualifierHierarchy.findAnnotationInHierarchy(java.util.Collection<? extends javax.lang.model.element.AnnotationMirror>, javax.lang.model.element.AnnotationMirror).
    
    Returns:
    
    a set of annotations
  - getUnderlyingType
```
@Pure
public TypeMirror getUnderlyingType()
```
  - equals
```
public boolean equals(@Nullable Object obj)
```
    Overrides:
    
    equals in class Object
  - hashCode
```
@Pure
public int hashCode()
```
    Overrides:
    
    hashCode in class Object
  - toStringFullyQualified
```
@SideEffectFree
public String toStringFullyQualified()
```
    Returns the string representation, using fully-qualified names.
    
    Returns:
    
    the string representation, using fully-qualified names
  - toStringSimple
```
@SideEffectFree
public String toStringSimple()
```
    Returns the string representation, using simple (not fully-qualified) names.
    
    Returns:
    
    the string representation, using simple (not fully-qualified) names
  - toString
```
@SideEffectFree
public String toString()
```
    Returns the string representation.
    
    Overrides:
    
    toString in class Object
    
    Returns:
    
    the string representation
  - mostSpecific
```
public V mostSpecific(V other,
                      V backup)
```
    Returns the more specific version of two values this and other. If they do not contain information for all hierarchies, then it is possible that information from both this and other are taken.
    If neither of the two is more specific for one of the hierarchies (i.e., if the two are incomparable as determined by QualifierHierarchy.isSubtype(AnnotationMirror, AnnotationMirror), then the respective value from backup is used.
  - leastUpperBound
```
public V leastUpperBound(V other)
```
    Description copied from interface: AbstractValue
    Compute the least upper bound of two values.
    Important: This method must fulfill the following contract:
    - Does not change this.
    - Does not change other.
    - Returns a fresh object which is not aliased yet.
    - Returns an object of the same (dynamic) type as this, even if the signature is more permissive.
    - Is commutative.
    Specified by:
    
    leastUpperBound in interface AbstractValue<V extends CFAbstractValue<V>>
  - widenUpperBound
```
public V widenUpperBound(V previous)
```
    Compute an upper bound of two values that is wider than the least upper bound of the two values. Used to jump to a higher abstraction to allow faster termination of the fixed point computations in Analysis.
    A particular analysis might not require widening and should implement this method by calling leastUpperBound.
    Important: This method must fulfill the following contract:
    - Does not change this.
    - Does not change previous.
    - Returns a fresh object which is not aliased yet.
    - Returns an object of the same (dynamic) type as this, even if the signature is more permissive.
    - Is commutative.
    Parameters:
    
    previous - must be the previous value
    
    Returns:
    
    an upper bound of two values that is wider than the least upper bound of the two values
  - greatestLowerBound
```
public V greatestLowerBound(V other)
```
    Compute the greatest lower bound of two values.
    Important: This method must fulfill the following contract:
    - Does not change this.
    - Does not change other.
    - Returns a fresh object which is not aliased yet.
    - Returns an object of the same (dynamic) type as this, even if the signature is more permissive.
    - Is commutative.
    Parameters:
    
    other - another value
    
    Returns:
    
    the greatest lower bound of two values

Class CFAbstractValue<V extends CFAbstractValue<V>>

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

analysis

underlyingType

annotations

Constructor Detail

CFAbstractValue

Method Detail

validateSet

canBeMissingAnnotations

getAnnotations

getUnderlyingType

equals

hashCode

toStringFullyQualified

toStringSimple

toString

mostSpecific

leastUpperBound

widenUpperBound

greatestLowerBound