Interface ElementVisitor<R,P>
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- Type Parameters:
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R- the return type of this visitor's methods. UseVoidfor visitors that do not need to return results. -
P- the type of the additional parameter to this visitor's methods. UseVoidfor visitors that do not need an additional parameter.
- All Known Implementing Classes:
- AbstractElementVisitor6, AbstractElementVisitor7, AbstractElementVisitor8, ElementKindVisitor6, ElementKindVisitor7, ElementKindVisitor8, ElementScanner6, ElementScanner7, ElementScanner8, SimpleElementVisitor6, SimpleElementVisitor7, SimpleElementVisitor8
public interface ElementVisitor<R,P>A visitor of program elements, in the style of the visitor design pattern. Classes implementing this interface are used to operate on an element when the kind of element is unknown at compile time. When a visitor is passed to an element'sacceptmethod, the visitXYZ method most applicable to that element is invoked.Classes implementing this interface may or may not throw a
NullPointerExceptionif the additional parameterpisnull; 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.
Note that methods to accommodate new language constructs could be added in a source compatible way if they were added as default methods. However, default methods are only available on Java SE 8 and higher releases and the
javax.lang.model.*packages bundled in Java SE 8 are required to also be runnable on Java SE 7. Therefore, default methods cannot be used when extendingjavax.lang.model.*to cover Java SE 8 language features. However, default methods may be used in subsequent revisions of thejavax.lang.model.*packages that are only required to run on Java SE 8 and higher platform versions.- Since:
- 1.6
- See Also:
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AbstractElementVisitor6,AbstractElementVisitor7
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Method Summary
All Methods Instance Methods Abstract Methods Modifier and Type Method and Description Rvisit(Element e)A convenience method equivalent tov.visit(e, null).Rvisit(Element e, P p)Visits an element.RvisitExecutable(ExecutableElement e, P p)Visits an executable element.RvisitPackage(PackageElement e, P p)Visits a package element.RvisitType(TypeElement e, P p)Visits a type element.RvisitTypeParameter(TypeParameterElement e, P p)Visits a type parameter element.RvisitUnknown(Element e, P p)Visits an unknown kind of element.RvisitVariable(VariableElement e, P p)Visits a variable element.
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Method Detail
visit
R visit(Element e, P p)
Visits an element.- Parameters:
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e- the element to visit -
p- a visitor-specified parameter - Returns:
- a visitor-specified result
visit
R visit(Element e)
A convenience method equivalent tov.visit(e, null).- Parameters:
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e- the element to visit - Returns:
- a visitor-specified result
visitPackage
R visitPackage(PackageElement e, P p)
Visits a package element.- Parameters:
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e- the element to visit -
p- a visitor-specified parameter - Returns:
- a visitor-specified result
visitType
R visitType(TypeElement e, P p)
Visits a type element.- Parameters:
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e- the element to visit -
p- a visitor-specified parameter - Returns:
- a visitor-specified result
visitVariable
R visitVariable(VariableElement e, P p)
Visits a variable element.- Parameters:
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e- the element to visit -
p- a visitor-specified parameter - Returns:
- a visitor-specified result
visitExecutable
R visitExecutable(ExecutableElement e, P p)
Visits an executable element.- Parameters:
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e- the element to visit -
p- a visitor-specified parameter - Returns:
- a visitor-specified result
visitTypeParameter
R visitTypeParameter(TypeParameterElement e, P p)
Visits a type parameter element.- Parameters:
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e- the element to visit -
p- a visitor-specified parameter - Returns:
- a visitor-specified result
visitUnknown
R visitUnknown(Element e, P p)
Visits an unknown kind of element. This can occur if the language evolves and new kinds of elements are added to theElementhierarchy.- Parameters:
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e- the element to visit -
p- a visitor-specified parameter - Returns:
- a visitor-specified result
- Throws:
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UnknownElementException- a visitor implementation may optionally throw this exception
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Submit a bug or feature
For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
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