javax.lang.model.util
class ElementScanner6

java.lang.Object javax.lang.model.util.AbstractElementVisitor6 javax.lang.model.util.ElementScanner6

All Implemented Interfaces:

ElementVisitor

public class ElementScanner6
extends AbstractElementVisitor6

A scanning visitor of program elements with default behavior appropriate for the {@link SourceVersion#RELEASE_6 RELEASE_6} source version. The visitXYZ methods in this class scan their component elements by calling {@code scan} on their {@linkplain Element#getEnclosedElements enclosed elements}, {@linkplain ExecutableElement#getParameters 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 {@code v.scan(e, p)} rather than {@code 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 {@code 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 {@link java.lang.Override @Override} will help ensure that methods are overridden as intended.

WARNING: The {@code 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 {@code "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 {@code "visit"}.

When such a new visit method is added, the default implementation in this class will be to call the {@link #visitUnknown 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.

DEFAULT_VALUE

protected final Object DEFAULT_VALUE

The specified default value.

ElementScanner6

protected ElementScanner6()

Constructor for concrete subclasses; uses {@code null} for the default value.

ElementScanner6

protected ElementScanner6(Object defaultValue)

Constructor for concrete subclasses; uses the argument for the default value.

Parameters:

defaultValue

scan

public final Object scan(Element e)

Convenience method equivalent to {@code v.scan(e, null)}.

Parameters:

e

Returns:

the result of scanning {@code e}.

scan

public Object scan(Element e,
                   Object p)

Processes an element by calling {@code e.accept(this, p)}; this method may be overridden by subclasses.

Parameters:

e

p

Returns:

the result of visiting {@code e}.

scan

public final Object scan(Iterable iterable,
                         Object p)

Iterates over the given elements and calls {@link #scan(Element, Object) scan(Element, P)} on each one. Returns the result of the last call to {@code scan} or {@code DEFAULT_VALUE} for an empty iterable.

Parameters:

iterable - the elements to scan

p - additional parameter

Returns:

the scan of the last element or {@code DEFAULT_VALUE} if no elements

visitExecutable

public Object visitExecutable(ExecutableElement e,
                              Object p)

{@inheritDoc} This implementation scans the parameters.

Parameters:

e - the element to visit

p - a visitor-specified parameter

Returns:

the result of scanning

visitPackage

public Object visitPackage(PackageElement e,
                           Object p)

{@inheritDoc} This implementation scans the enclosed elements.

Parameters:

e - the element to visit

p - a visitor-specified parameter

Returns:

the result of scanning

visitType

public Object visitType(TypeElement e,
                        Object p)

{@inheritDoc} This implementation scans the enclosed elements.

Parameters:

e - the element to visit

p - a visitor-specified parameter

Returns:

the result of scanning

visitTypeParameter

public Object visitTypeParameter(TypeParameterElement e,
                                 Object p)

{@inheritDoc} This implementation scans the enclosed elements.

Parameters:

e - the element to visit

p - a visitor-specified parameter

Returns:

the result of scanning

visitVariable

public Object visitVariable(VariableElement e,
                            Object p)

{@inheritDoc} This implementation scans the enclosed elements.

Parameters:

e - the element to visit

p - a visitor-specified parameter

Returns:

the result of scanning