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TypeVisitor (Java Platform SE 6) - JDK 5 Documentation v6.0, Java 2 SDK 英文文档


Java™ Platform
Standard Ed. 6

javax.lang.model.type
Interface TypeVisitor<R,P>

Type Parameters:
R - the return type of this visitor's methods. Use Void for visitors that do not need to return results.
P - the type of the additional parameter to this visitor's methods. Use Void for visitors that do not need an additional parameter.
All Known Implementing Classes:
AbstractTypeVisitor6, SimpleTypeVisitor6, TypeKindVisitor6

public interface TypeVisitor<R,P>

A visitor of types, in the style of the visitor design pattern. Classes implementing this interface are used to operate on a type when the kind of type is unknown at compile time. When a visitor is passed to a type's accept method, the visitXYZ method most applicable to that type is invoked.

Classes implementing this interface may or may not throw a NullPointerException if the additional parameter p is null; see documentation of the implementing class for details.

WARNING: It is possible that methods will be added to this interface to accommodate new, currently unknown, language structures added to future versions of the Java™ programming language. Therefore, visitor classes directly implementing this interface may be source incompatible with future versions of the platform. To avoid this source incompatibility, visitor implementations are encouraged to instead extend the appropriate abstract visitor class that implements this interface. However, an API should generally use this visitor interface as the type for parameters, return type, etc. rather than one of the abstract classes.

Since:
1.6

Method Summary
 R visit(TypeMirror t)
          A convenience method equivalent to v.visit(t, null).
 R visit(TypeMirror t, P p)
          Visits a type.
 R visitArray(ArrayType t, P p)
          Visits an array type.
 R visitDeclared(DeclaredType t, P p)
          Visits a declared type.
 R visitError(ErrorType t, P p)
          Visits an error type.
 R visitExecutable(ExecutableType t, P p)
          Visits an executable type.
 R visitNoType(NoType t, P p)
          Visits a NoType instance.
 R visitNull(NullType t, P p)
          Visits the null type.
 R visitPrimitive(PrimitiveType t, P p)
          Visits a primitive type.
 R visitTypeVariable(TypeVariable t, P p)
          Visits a type variable.
 R visitUnknown(TypeMirror t, P p)
          Visits an unknown kind of type.
 R visitWildcard(WildcardType t, P p)
          Visits a wildcard type.
 

Method Detail

visit

R visit(TypeMirror t,
        P p)
Visits a type.

Parameters:
t - the type to visit
p - a visitor-specified parameter
Returns:
a visitor-specified result

visit

R visit(TypeMirror t)
A convenience method equivalent to v.visit(t, null).

Parameters:
t - the element to visit
Returns:
a visitor-specified result

visitPrimitive

R visitPrimitive(PrimitiveType t,
                 P p)
Visits a primitive type.

Parameters:
t - the type to visit
p - a visitor-specified parameter
Returns:
a visitor-specified result

visitNull

R visitNull(NullType t,
            P p)
Visits the null type.

Parameters:
t - the type to visit
p - a visitor-specified parameter
Returns:
a visitor-specified result

visitArray

R visitArray(ArrayType t,
             P p)
Visits an array type.

Parameters:
t - the type to visit
p - a visitor-specified parameter
Returns:
a visitor-specified result

visitDeclared

R visitDeclared(DeclaredType t,
                P p)
Visits a declared type.

Parameters:
t - the type to visit
p - a visitor-specified parameter
Returns:
a visitor-specified result

visitError

R visitError(ErrorType t,
             P p)
Visits an error type.

Parameters:
t - the type to visit
p - a visitor-specified parameter
Returns:
a visitor-specified result

visitTypeVariable

R visitTypeVariable(TypeVariable t,
                    P p)
Visits a type variable.

Parameters:
t - the type to visit
p - a visitor-specified parameter
Returns:
a visitor-specified result

visitWildcard

R visitWildcard(WildcardType t,
                P p)
Visits a wildcard type.

Parameters:
t - the type to visit
p - a visitor-specified parameter
Returns:
a visitor-specified result

visitExecutable

R visitExecutable(ExecutableType t,
                  P p)
Visits an executable type.

Parameters:
t - the type to visit
p - a visitor-specified parameter
Returns:
a visitor-specified result

visitNoType

R visitNoType(NoType t,
              P p)
Visits a NoType instance.

Parameters:
t - the type to visit
p - a visitor-specified parameter
Returns:
a visitor-specified result

visitUnknown

R visitUnknown(TypeMirror t,
               P p)
Visits an unknown kind of type. This can occur if the language evolves and new kinds of types are added to the TypeMirror hierarchy.

Parameters:
t - the type to visit
p - a visitor-specified parameter
Returns:
a visitor-specified result
Throws:
UnknownTypeException - a visitor implementation may optionally throw this exception

Java™ Platform
Standard Ed. 6

Submit a bug or feature
For further API reference and developer documentation, see Java SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

Copyright 2006 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.