Package org.codehaus.groovy.control

Class GenericsVisitor

java.lang.Object

org.codehaus.groovy.ast.CodeVisitorSupport

org.codehaus.groovy.ast.ClassCodeVisitorSupport

org.codehaus.groovy.control.GenericsVisitor

All Implemented Interfaces:

GroovyClassVisitor, GroovyCodeVisitor, ErrorCollecting

public class GenericsVisitor
extends ClassCodeVisitorSupport

Verify correct usage of generics. This includes:

• class header (class and superclass declaration)
• arity of type parameters for fields, parameters, local variables
• invalid diamond <> usage
• JLS well-formedness of type arguments, bounds, array creation, and type parameters

Constructor Summary

Constructors

Constructor	Description
GenericsVisitor(SourceUnit source)	Creates a visitor that validates generic type usage for one source unit.

Method Summary

Modifier and Type	Method	Description
protected SourceUnit	getSourceUnit()	Returns the source unit currently being verified.
void	visitArrayExpression(ArrayExpression expression)	Validates generic usage for array element types.
void	visitBinaryExpression(BinaryExpression expression)	Groovy represents the type operand of instanceof as a ClassExpression, but it is not a class literal (T.class).
void	visitCastExpression(CastExpression expression)	Validates generic usage for cast target types.
void	visitCatchStatement(CatchStatement statement)	JLS 14.20: a catch type must be a reifiable class or union; a type parameter is not reifiable and may not be caught.
void	visitClass(ClassNode node)	Validates generic usage in a class header and its contents.
void	visitClassExpression(ClassExpression expression)	JLS 15.8.2: a class literal may not name a type variable or a parameterized type (T.class, Cell<String>.class).
void	visitConstructorCallExpression(ConstructorCallExpression expression)	Validates generic usage on constructor call types.
protected void	visitConstructorOrMethod(MethodNode node, boolean isConstructor)	Validates generic usage for a constructor or method signature.
void	visitDeclarationExpression(DeclarationExpression expression)	Validates generic usage in declared variable types.
void	visitField(FieldNode node)	Validates generic usage for a field declaration.
void	visitMethodCallExpression(MethodCallExpression call)	JLS 4.5.2: a static member of a generic type must be referred to by the generic type name, not a parameterization such as Cell<String>.id().
void	visitMethodPointerExpression(MethodPointerExpression expression)	JLS 15.13: TypeName::m and TypeName::new are method or constructor references, not class literals.
void	visitPropertyExpression(PropertyExpression expression)	JLS 4.5.2 also applies to static fields accessed as Cell<String>.ID.

Methods inherited from class org.codehaus.groovy.ast.ClassCodeVisitorSupport

addError, visitAnnotation, visitAnnotations, visitAnnotations, visitAssertStatement, visitBlockStatement, visitBreakStatement, visitCaseStatement, visitClassCodeContainer, visitClosureExpression, visitConstructor, visitContinueStatement, visitDoWhileLoop, visitExpressionStatement, visitForLoop, visitIfElse, visitImports, visitMethod, visitObjectInitializerStatements, visitPackage, visitProperty, visitReturnStatement, visitStatement, visitStatementAnnotations, visitSwitch, visitSynchronizedStatement, visitThrowStatement, visitTryCatchFinally, visitWhileLoop, visitYieldStatement

Methods inherited from class org.codehaus.groovy.ast.CodeVisitorSupport

afterSwitchCaseStatementsVisited, afterSwitchCaseStatementsVisited, afterSwitchConditionExpressionVisited, afterSwitchConditionExpressionVisited, visitArgumentlistExpression, visitAttributeExpression, visitBitwiseNegationExpression, visitBooleanExpression, visitBytecodeExpression, visitClosureListExpression, visitConstantExpression, visitEmptyStatement, visitFieldExpression, visitGStringExpression, visitLambdaExpression, visitListExpression, visitMapEntryExpression, visitMapExpression, visitMethodReferenceExpression, visitNotExpression, visitPostfixExpression, visitPrefixExpression, visitRangeExpression, visitShortTernaryExpression, visitSpreadExpression, visitSpreadMapExpression, visitStaticMethodCallExpression, visitSwitchExpression, visitTernaryExpression, visitTupleExpression, visitUnaryMinusExpression, visitUnaryPlusExpression, visitVariableExpression

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.codehaus.groovy.ast.GroovyCodeVisitor

visit, visit, visitEmptyExpression, visitListOfExpressions

Constructor Details

GenericsVisitor

public GenericsVisitor(SourceUnit source)

Creates a visitor that validates generic type usage for one source unit.

Parameters:

source - the source unit being verified

Method Details

getSourceUnit

protected SourceUnit getSourceUnit()

Returns the source unit currently being verified.

Specified by:

getSourceUnit in class ClassCodeVisitorSupport

Returns:

the active source unit

visitClass

public void visitClass(ClassNode node)

Validates generic usage in a class header and its contents.

Specified by:

visitClass in interface GroovyClassVisitor

Overrides:

visitClass in class ClassCodeVisitorSupport

Parameters:

node - the class to inspect

visitField

public void visitField(FieldNode node)

Validates generic usage for a field declaration.

Specified by:

visitField in interface GroovyClassVisitor

Overrides:

visitField in class ClassCodeVisitorSupport

Parameters:

node - the field to inspect

visitCatchStatement

public void visitCatchStatement(CatchStatement statement)

JLS 14.20: a catch type must be a reifiable class or union; a type parameter is not reifiable and may not be caught.

Specified by:

visitCatchStatement in interface GroovyCodeVisitor

Overrides:

visitCatchStatement in class ClassCodeVisitorSupport

Parameters:

statement - the catch statement to visit

visitConstructorOrMethod

protected void visitConstructorOrMethod(MethodNode node,
 boolean isConstructor)

Validates generic usage for a constructor or method signature.

Overrides:

visitConstructorOrMethod in class ClassCodeVisitorSupport

Parameters:

node - the executable member to inspect

isConstructor - whether node is a constructor

visitConstructorCallExpression

public void visitConstructorCallExpression(ConstructorCallExpression expression)

Validates generic usage on constructor call types.

Specified by:

visitConstructorCallExpression in interface GroovyCodeVisitor

Overrides:

visitConstructorCallExpression in class CodeVisitorSupport

Parameters:

expression - the constructor call to inspect

visitDeclarationExpression

public void visitDeclarationExpression(DeclarationExpression expression)

Validates generic usage in declared variable types.

Specified by:

visitDeclarationExpression in interface GroovyCodeVisitor

Overrides:

visitDeclarationExpression in class ClassCodeVisitorSupport

Parameters:

expression - the declaration expression to inspect

visitArrayExpression

public void visitArrayExpression(ArrayExpression expression)

Validates generic usage for array element types.

Specified by:

visitArrayExpression in interface GroovyCodeVisitor

Overrides:

visitArrayExpression in class CodeVisitorSupport

Parameters:

expression - the array expression to inspect

visitClassExpression

public void visitClassExpression(ClassExpression expression)

JLS 15.8.2: a class literal may not name a type variable or a parameterized type (T.class, Cell<String>.class). After resolve, Foo.class is a ClassExpression; Foo<String>.class may still be a PropertyExpression whose object is that class expression — see visitPropertyExpression(org.codehaus.groovy.ast.expr.PropertyExpression). ClassExpression is also the TypeName of a static qualifier, instanceof operand, or method reference; those parents visit the type without entering this method, so a class-literal check here is only for an actual class literal.

Specified by:

visitClassExpression in interface GroovyCodeVisitor

Overrides:

visitClassExpression in class CodeVisitorSupport

Parameters:

expression - the class expression

visitBinaryExpression

public void visitBinaryExpression(BinaryExpression expression)

Groovy represents the type operand of instanceof as a ClassExpression, but it is not a class literal (T.class). Do not visit that operand as a class expression (that would reject instanceof T as T.class). Still run checkGenericsUsage(ClassNode) so nested-type well-formedness applies (Outer<?>.Inner with a generic Inner, Outer.Inner<?>). Parameterized instanceof is handled at parse (AstBuilder#rejectNonReifiableInstanceof): the grammar allows type arguments so instanceof List<?> can parse, while instanceof Map<String,Integer> is rejected (JLS 15.20.2). InstanceOfVerifier then checks primitives and type-parameter targets.

Specified by:

visitBinaryExpression in interface GroovyCodeVisitor

Overrides:

visitBinaryExpression in class CodeVisitorSupport

Parameters:

expression - the binary expression

visitMethodCallExpression

public void visitMethodCallExpression(MethodCallExpression call)

JLS 4.5.2: a static member of a generic type must be referred to by the generic type name, not a parameterization such as Cell<String>.id().

Specified by:

visitMethodCallExpression in interface GroovyCodeVisitor

Overrides:

visitMethodCallExpression in class CodeVisitorSupport

Parameters:

call - the method call expression

visitPropertyExpression

public void visitPropertyExpression(PropertyExpression expression)

JLS 4.5.2 also applies to static fields accessed as Cell<String>.ID. JLS 15.8.2: Cell<String>.class is a class literal, not a static member selection — do not use the 4.5.2 diagnostic for .class.

Specified by:

visitPropertyExpression in interface GroovyCodeVisitor

Overrides:

visitPropertyExpression in class CodeVisitorSupport

Parameters:

expression - the property expression

visitMethodPointerExpression

public void visitMethodPointerExpression(MethodPointerExpression expression)

JLS 15.13: TypeName::m and TypeName::new are method or constructor references, not class literals. A parameterization of TypeName is legal for an instance method or constructor reference (Iterable<String>::asCollection, HashMap<String,Integer>::new).

Specified by:

visitMethodPointerExpression in interface GroovyCodeVisitor

Overrides:

visitMethodPointerExpression in class CodeVisitorSupport

Parameters:

expression - the method pointer expression

visitCastExpression

public void visitCastExpression(CastExpression expression)

Validates generic usage for cast target types.

Specified by:

visitCastExpression in interface GroovyCodeVisitor

Overrides:

visitCastExpression in class CodeVisitorSupport

Parameters:

expression - the cast expression to inspect