Class ElementScannerPreview<R,P>

java.lang.Object
javax.lang.model.util.AbstractElementVisitor6<R,P>
javax.lang.model.util.ElementScanner6<R,P>
javax.lang.model.util.ElementScanner7<R,P>
javax.lang.model.util.ElementScanner8<R,P>
javax.lang.model.util.ElementScanner9<R,P>
javax.lang.model.util.ElementScanner14<R,P>
javax.lang.model.util.ElementScannerPreview<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 Implemented Interfaces:
ElementVisitor<R,P>
@SupportedSourceVersion(RELEASE_25) public class ElementScannerPreview<R,P> extends ElementScanner14<R,P>
ElementScannerPreview is a reflective preview API of the Java platform.
Preview features may be removed in a future release, or upgraded to permanent features of the Java platform.
A scanning visitor of program elements with default behavior appropriate for a preview 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 by 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.

API Note:
Methods in this class may be overridden subject to their general contract.
Since:
23
See Also:

  • Constructor Details

    • ElementScannerPreview

      protected ElementScannerPreview()
      Constructor for concrete subclasses; uses null for the default value.

    • ElementScannerPreview

      protected ElementScannerPreview(R defaultValue)
      Constructor for concrete subclasses; uses the argument for the default value.
      Parameters:
      defaultValue - the default value