checkers.basetype
Class BaseTypeChecker

java.lang.Object
  javax.annotation.processing.AbstractProcessor
      checkers.source.SourceChecker
          checkers.basetype.BaseTypeChecker

All Implemented Interfaces:

Processor

Direct Known Subclasses:

BasicChecker, FlowTestChecker, IGJChecker, InterningChecker, JavariChecker, NullnessChecker, TestChecker

public abstract class BaseTypeChecker
extends SourceChecker

An abstract SourceChecker that provides a simple SourceVisitor implementation for typical assignment and pseudo-assignment checking of annotated types. Pseudo-assignment checks include method overriding checks, parameter passing, and method invocation. Most type-checker plug-ins will want to extend this class, instead of SourceChecker. Checkers which require annotated types but not subtype checking (e.g. for testing purposes) should extend SourceChecker. Non-type checkers (e.g. for enforcing coding styles) should extend AbstractProcessor (or even SourceChecker) as the Checker Framework is not designed for such checkers. Non-type checkers (e.g. checkers to enforce coding styles) should extend SourceChecker or AbstractProcessor directly; the Checker Framework is not designed for such checkers.

It is a convention that, for a type system Foo, the checker, the visitor, and the annotated type factory are named as FooChecker, FooVisitor, and FooAnnotatedTypeFactory. Some factory methods uses this convention to construct the appriopriate classes reflectively.

BaseTypeChecker encapsulates a group for factories for various representations/classes related the type system, mainly:

• QualifierHierarchy: to represent the supported qualifiers in addition to their hierarchy, mainly, subtyping rules
• TypeHierarchy: to check subtyping rules between annotated types rather than qualifiers
• AnnotatedTypeFactory: to construct qualified types enriched with implicit qualifiers according to the type system rules
• BaseTypeVisitor: to visit the compiled Java files and check for violations of the type system rules

Subclasses must specify the set of type qualifiers they support either by annotating the subclass with TypeQualifiers or by overriding the getSupportedTypeQualifiers() method.

If the specified type qualifiers are meta-annotated with SubtypeOf, this implementation will automatically construct the type qualifier hierarchy. Otherwise, or if this behavior must be overridden, the subclass may override the createQualifierHierarchy() method.

See Also:

checkers.quals

Field Summary

Fields inherited from class checkers.source.SourceChecker

currentRoot, env, messager, messages, skipPattern, trees

Fields inherited from class javax.annotation.processing.AbstractProcessor

processingEnv

Constructor Summary

BaseTypeChecker()

Method Summary

AnnotatedTypeFactory	createFactory(CompilationUnitTree root) Constructs an instance of the appropriate type factory for the implemented type system.
protected QualifierHierarchy	createQualifierHierarchy() Returns the type qualifier hierarchy graph to be used by this processor.
protected BaseTypeVisitor<?,?>	createSourceVisitor(CompilationUnitTree root) Returns the appropriate visitor that type checks the compilation unit according to the type system rules.
protected Set<Class<? extends Annotation>>	createSupportedTypeQualifiers() If the checker class is annotated with TypeQualifiers, return an immutable set with the same set of classes as the annotation.
protected TypeHierarchy	createTypeHierarchy() Creates the type subtyping checker using the current type qualifier hierarchy.
QualifierHierarchy	getQualifierHierarchy() Returns the type qualifier hierarchy graph to be used by this processor.
Set<String>	getSupportedLintOptions() Specify 'flow' and 'cast' as supported lint options for all Type checkers
Set<Class<? extends Annotation>>	getSupportedTypeQualifiers() Returns an immutable set of the type qualifiers supported by this checker.
void	init(ProcessingEnvironment processingEnv)
boolean	isAssignable(AnnotatedTypeMirror varType, AnnotatedTypeMirror receiverType, Tree variable) Tests whether the variable accessed is an assignable variable or not, given the current scope
boolean	isSubtype(AnnotatedTypeMirror sub, AnnotatedTypeMirror sup) Tests whether one annotated type is a subtype of another, with respect to the annotations on these types.
boolean	isValidUse(AnnotatedTypeMirror.AnnotatedDeclaredType declarationType, AnnotatedTypeMirror.AnnotatedDeclaredType useType) Tests that the qualifiers present on the useType are valid qualifiers, given the qualifiers on the declaration of the type, declarationType.

Methods inherited from class checkers.source.SourceChecker

attribute, getLintOption, getLintOption, getMessages, getProcessingEnvironment, getShouldSkip, getSupportedAnnotationTypes, getSupportedOptions, getSupportedSourceVersion, getSuppressWarningsKey, message, process, report, shouldSkip

Methods inherited from class javax.annotation.processing.AbstractProcessor

getCompletions, isInitialized

Methods inherited from class java.lang.Object

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

Constructor Detail

BaseTypeChecker

public BaseTypeChecker()

Method Detail

init

public void init(ProcessingEnvironment processingEnv)

Description copied from class: SourceChecker

Specified by:

init in interface Processor

Overrides:

init in class SourceChecker

See Also:

AbstractProcessor.init(ProcessingEnvironment)

createSupportedTypeQualifiers

protected Set<Class<? extends Annotation>> createSupportedTypeQualifiers()

If the checker class is annotated with TypeQualifiers, return an immutable set with the same set of classes as the annotation. If the class is not so annotated, return an empty set. Subclasses may override this method to return an immutable set of their supported type qualifiers.

Returns:

the type qualifiers supported this processor, or an empty set if none

See Also:

TypeQualifiers

getSupportedTypeQualifiers

public final Set<Class<? extends Annotation>> getSupportedTypeQualifiers()

Returns an immutable set of the type qualifiers supported by this checker.

Returns:

the type qualifiers supported this processor, or an empty set if none

See Also:

createSupportedTypeQualifiers()

createQualifierHierarchy

protected QualifierHierarchy createQualifierHierarchy()

Returns the type qualifier hierarchy graph to be used by this processor. The implementation builds the type qualifier hierarchy for the getSupportedTypeQualifiers() using the meta-annotations found in them. The current implementation returns an instance of GraphQualifierHierarchy. Subclasses may override this method to express any relationships that cannot be inferred using meta-annotations (e.g. due to lack of meta-annotations).

Returns:

an annotation relation tree representing the supported qualifiers

getQualifierHierarchy

public final QualifierHierarchy getQualifierHierarchy()

Returns the type qualifier hierarchy graph to be used by this processor.

Returns:

the QualifierHierarchy for this checker

See Also:

createQualifierHierarchy()

createTypeHierarchy

protected TypeHierarchy createTypeHierarchy()

Creates the type subtyping checker using the current type qualifier hierarchy. Subclasses may override this method to specify new type checking rules beyond the typical java subtyping rules.

Returns:

the type relations class to check type subtyping

createSourceVisitor

protected BaseTypeVisitor<?,?> createSourceVisitor(CompilationUnitTree root)

Returns the appropriate visitor that type checks the compilation unit according to the type system rules. This implementation uses the checker naming convention to create the appropriate visitor. If no visitor is found, it returns an instance of BaseTypeVisitor. It reflectively invokes the constructor that accepts this checker and the compilation unit tree (in that order) as arguments. Subclasses have to override this method to create the appropriate visitor if they do not follow the checker naming convention.

Specified by:

createSourceVisitor in class SourceChecker

Parameters:

root - the compilation unit currently being visited

Returns:

the type-checking visitor

createFactory

public AnnotatedTypeFactory createFactory(CompilationUnitTree root)

Constructs an instance of the appropriate type factory for the implemented type system. The default implementation uses the checker naming convention to create the appropriate type factory. If no factory is found, it returns BasicAnnotatedTypeFactory. It reflectively invokes the constructor that accepts this checker and compilation unit tree (in that order) as arguments. Subclasses have to override this method to create the appropriate visitor if they do not follow the checker naming convention.

Overrides:

createFactory in class SourceChecker

Parameters:

root - the currently visited compilation unit

Returns:

the appropriate type factory

isSubtype

public boolean isSubtype(AnnotatedTypeMirror sub,
                         AnnotatedTypeMirror sup)

Tests whether one annotated type is a subtype of another, with respect to the annotations on these types. Subclasses may wish to ignore annotations that are not related to the type qualifiers they check. This implementation follows the subtype rules specified in TypeHierarchy. Its behavior is undefined for any annotations not specified by either TypeQualifiers or the result of getSupportedTypeQualifiers().

Parameters:

sub - the child type

sup - the parent type

Returns:

true iff sub is a subtype of sup

isValidUse

public boolean isValidUse(AnnotatedTypeMirror.AnnotatedDeclaredType declarationType,
                          AnnotatedTypeMirror.AnnotatedDeclaredType useType)

Tests that the qualifiers present on the useType are valid qualifiers, given the qualifiers on the declaration of the type, declarationType.

The check is shallow, as it does not descend into generic or array types (i.e. only performing the validity check on the raw type or outmost array dimension). BaseTypeVisitor.validateTypeOf(Tree) would call this for each type argument or array dimention separately.

For instance, in the IGJ type system, a @Mutable is an invalid qualifier for String, as String is declared as @Immutable String.

In most cases, useType simply needs to be a subtype of declarationType, but there are exceptions. In IGJ, a variable may be declared @ReadOnly String, even though String is @Immutable String; ReadOnly is not a subtype of Immutable.

Parameters:

declarationType - the type of the class (TypeElement)

useType - the use of the class (instance type)

Returns:

if the useType is a valid use of elemType

isAssignable

public boolean isAssignable(AnnotatedTypeMirror varType,
                            AnnotatedTypeMirror receiverType,
                            Tree variable)

Tests whether the variable accessed is an assignable variable or not, given the current scope

Parameters:

varType - the annotated variable type

variable - tree used to access the variable

Returns:

true iff variable is assignable in the current scope

getSupportedLintOptions

public Set<String> getSupportedLintOptions()

Specify 'flow' and 'cast' as supported lint options for all Type checkers

Overrides:

getSupportedLintOptions in class SourceChecker

Returns:

an unmodifiable Set of the lint options recognized by this checker