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package javax.lang.model.util;
import java.util.List;
import java.util.ArrayList;
import javax.lang.model.element.*;
import javax.annotation.processing.SupportedSourceVersion;
import javax.lang.model.SourceVersion;
import static javax.lang.model.SourceVersion.*;
/**
* A scanning visitor of program elements with default behavior
* appropriate for the {@link SourceVersion#RELEASE_14 RELEASE_14}
* 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.
*
* @apiNote
* Methods in this class may be overridden subject to their general
* contract.
*
* @param the return type of this visitor's methods. Use {@link
* Void} for visitors that do not need to return results.
* @param the type of the additional parameter to this visitor's
* methods. Use {@code Void} for visitors that do not need an
* additional parameter.
*
* @see Compatibility note for subclasses
* @see ElementScanner6
* @see ElementScanner7
* @see ElementScanner8
* @see ElementScanner9
* @since 16
*/
@SupportedSourceVersion(RELEASE_17)
public class ElementScanner14 extends ElementScanner9 {
/**
* Constructor for concrete subclasses; uses {@code null} for the
* default value.
*/
protected ElementScanner14(){
super(null);
}
/**
* Constructor for concrete subclasses; uses the argument for the
* default value.
*
* @param defaultValue the default value
*/
protected ElementScanner14(R defaultValue){
super(defaultValue);
}
/**
* {@inheritDoc}
*
* @implSpec This implementation scans the type parameters, if
* any, and then the enclosed elements.
*
*
* @param e {@inheritDoc}
* @param p {@inheritDoc}
* @return the result of scanning
*/
@Override
public R visitType(TypeElement e, P p) {
return scan(createScanningList(e, e.getEnclosedElements()), p);
}
/**
* {@inheritDoc}
*
* @implSpec This implementation first scans the type parameters, if any, and then
* the parameters.
*
* @param e {@inheritDoc}
* @param p {@inheritDoc}
* @return the result of scanning
*/
public R visitExecutable(ExecutableElement e, P p) {
return scan(createScanningList(e, e.getParameters()), p);
}
private List createScanningList(Parameterizable element,
List toBeScanned) {
List typeParameters = element.getTypeParameters();
if (typeParameters.isEmpty()) {
return toBeScanned;
} else {
List scanningList = new ArrayList<>(typeParameters);
scanningList.addAll(toBeScanned);
return scanningList;
}
}
/**
* {@inheritDoc}
*
* @implSpec This implementation scans the enclosed elements.
*
* @param e the element to visit
* @param p a visitor-specified parameter
* @return the result of the scan
*/
@Override
public R visitRecordComponent(RecordComponentElement e, P p) {
return scan(e.getEnclosedElements(), p);
}
}