R- the return type of this visitor's methods. Use
Voidfor visitors that do not need to return results.
P- the type of the additional parameter to this visitor's methods. Use
Voidfor visitors that do not need an additional parameter.
@SupportedSourceVersion(RELEASE_8) public class ElementScanner8<R,P> extends ElementScanner7<R,P>
RELEASE_8source version. The
visitXyzmethods in this class scan their component elements by calling
scanon their enclosed elements, parameters, etc., as indicated in the individual method specifications. A subclass can control the order elements are visited by overriding the
visitXyzmethods. Note that clients of a scanner may get the desired behavior be invoking
v.scan(e, p)rather than
v.visit(e, p)on the root objects of interest.
When a subclass overrides a
visitXyz method, the
new method can cause the enclosed elements to be scanned in the
default way by calling
super.visitXyz. In this
fashion, the concrete visitor can control the ordering of traversal
over the component elements with respect to the additional
processing; for example, consistently calling
super.visitXyz at the start of the overridden
methods will yield a preorder traversal, etc. If the component
elements should be traversed in some other order, instead of
super.visitXyz, an overriding visit method
scan with the elements in the desired order.
Methods in this class may be overridden subject to their
general contract. Note that annotating methods in concrete
@Override will help
ensure that methods are overridden as intended.
implemented by this class may have methods added to it in the
future to accommodate new, currently unknown, language structures
added to future versions of the Java™ programming language.
Therefore, methods whose names begin with
"visit" may be
added to this class in the future; to avoid incompatibilities,
classes which extend this class should not declare any instance
methods with names beginning with
When such a new visit method is added, the default
implementation in this class will be to call the
visitUnknown method. A new element scanner visitor
class will also be introduced to correspond to the new language
level; this visitor will have different default behavior for the
visit method in question. When the new visitor is introduced, all
or portions of this visitor may be deprecated.
Constructor for concrete subclasses; uses
Constructor for concrete subclasses; uses the argument for the default value.
visit, visit, visitModule, visitUnknown
scan, scan, scan, visitExecutable, visitPackage, visitType, visitTypeParameter
nullfor the default value.
protected ElementScanner8(R defaultValue)
defaultValue- the default value
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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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