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.@SupportedSourceVersion(value=RELEASE_6) public class ElementScanner6<R,P> extends AbstractElementVisitor6<R,P>
RELEASE_6
source version. The visitXYZ methods in this
class scan their component elements by calling scan on
their enclosed elements,
parameters, etc., as
indicated in the individual method specifications. A subclass can
control the order elements are visited by overriding the
visitXYZ methods. 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
calling super.visitXYZ, an overriding visit method
should call 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
subclasses with @Override will help
ensure that methods are overridden as intended.
WARNING: The ElementVisitor interface
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 "visit".
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.
ElementScanner7,
ElementScanner8| Modifier and Type | Field and Description |
|---|---|
protected R |
DEFAULT_VALUE
The specified default value.
|
| Modifier | Constructor and Description |
|---|---|
protected |
ElementScanner6()
Constructor for concrete subclasses; uses
null for the
default value. |
protected |
ElementScanner6(R defaultValue)
Constructor for concrete subclasses; uses the argument for the
default value.
|
| Modifier and Type | Method and Description |
|---|---|
R |
scan(Element e)
Convenience method equivalent to
v.scan(e, null). |
R |
scan(Element e,
P p)
Processes an element by calling
e.accept(this, p);
this method may be overridden by subclasses. |
R |
scan(Iterable<? extends Element> iterable,
P p)
Iterates over the given elements and calls
scan(Element, P) on each one. |
R |
visitExecutable(ExecutableElement e,
P p)
Visits an executable element.
|
R |
visitPackage(PackageElement e,
P p)
Visits a package element.
|
R |
visitType(TypeElement e,
P p)
Visits a type element.
|
R |
visitTypeParameter(TypeParameterElement e,
P p)
Visits a type parameter element.
|
R |
visitVariable(VariableElement e,
P p)
Visits a variable element.
|
visit, visit, visitUnknownprotected final R DEFAULT_VALUE
protected ElementScanner6()
null for the
default value.protected ElementScanner6(R defaultValue)
defaultValue - the default valuepublic final R scan(Iterable<? extends Element> iterable, P p)
scan(Element, P) on each one. Returns
the result of the last call to scan or DEFAULT_VALUE for an empty iterable.iterable - the elements to scanp - additional parameterDEFAULT_VALUE if no elementspublic R scan(Element e, P p)
e.accept(this, p);
this method may be overridden by subclasses.e - the element to scanp - a scanner-specified parametere.public final R scan(Element e)
v.scan(e, null).e - the element to scane.public R visitPackage(PackageElement e, P p)
e - the element to visitp - a visitor-specified parameterpublic R visitType(TypeElement e, P p)
e - the element to visitp - a visitor-specified parameterpublic R visitVariable(VariableElement e, P p)
RESOURCE_VARIABLE in which case visitUnknown is called.e - the element to visitp - a visitor-specified parameterpublic R visitExecutable(ExecutableElement e, P p)
e - the element to visitp - a visitor-specified parameterpublic R visitTypeParameter(TypeParameterElement e, P p)
e - the element to visitp - a visitor-specified parameter 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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