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package javax.lang.model.util;

import javax.lang.model.element.*;
import javax.annotation.processing.SupportedSourceVersion;
import static javax.lang.model.SourceVersion.*;
import javax.lang.model.SourceVersion;


A visitor of program elements based on their kind with default behavior appropriate for the RELEASE_9 source version. For elements Xyz that may have more than one
kind, the visitXyz methods in this class delegate
to the visitXyzAsKind method corresponding to the
first argument's kind.  The visitXyzAsKind methods call defaultAction, passing their arguments to defaultAction's corresponding parameters. 
 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 or the ElementKind enum used in this case may have constants 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 abstract element kind 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. 
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.
See Also:
Since:9
@specJPMS
/**
 * A visitor of program elements based on their {@linkplain
 * ElementKind kind} with default behavior appropriate for the {@link
 * SourceVersion#RELEASE_9 RELEASE_9} source version.  For {@linkplain
 * Element elements} <code><i>Xyz</i></code> that may have more than one
 * kind, the <code>visit<i>Xyz</i></code> methods in this class delegate
 * to the <code>visit<i>Xyz</i>As<i>Kind</i></code> method corresponding to the
 * first argument's kind.  The <code>visit<i>Xyz</i>As<i>Kind</i></code> methods
 * call {@link #defaultAction defaultAction}, passing their arguments
 * to {@code defaultAction}'s corresponding parameters.
 *
 * <p> 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.
 *
 * <p> <b>WARNING:</b> The {@code ElementVisitor} interface
 * implemented by this class may have methods added to it or the
 * {@code ElementKind} {@code enum} used in this case may have
 * constants added to it in the future to accommodate new, currently
 * unknown, language structures added to future versions of the
 * Java&trade; 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"}.
 *
 * <p>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 abstract element kind
 * 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.
 *
 * @param <R> the return type of this visitor's methods.  Use {@link
 *            Void} for visitors that do not need to return results.
 * @param <P> the type of the additional parameter to this visitor's
 *            methods.  Use {@code Void} for visitors that do not need an
 *            additional parameter.
 *
 * @see ElementKindVisitor6
 * @see ElementKindVisitor7
 * @see ElementKindVisitor8
 * @since 9
 * @spec JPMS
 */
@SupportedSourceVersion(RELEASE_9)
public class ElementKindVisitor9<R, P> extends ElementKindVisitor8<R, P> {
    
Constructor for concrete subclasses; uses null for the default value. 
/**
     * Constructor for concrete subclasses; uses {@code null} for the
     * default value.
     */
    protected ElementKindVisitor9() {
        super(null);
    }

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

Params:
/**
     * Constructor for concrete subclasses; uses the argument for the
     * default value.
     *
     * @param defaultValue the value to assign to {@link #DEFAULT_VALUE}
     */
    protected ElementKindVisitor9(R defaultValue) {
        super(defaultValue);
    }

    
Visits a ModuleElement by calling 
defaultAction. 
Params:
  • e – the element to visit
  • p – a visitor-specified parameter
Returns: the result of defaultAction
/**
     * Visits a {@code ModuleElement} by calling {@code
     * defaultAction}.
     *
     * @param e the element to visit
     * @param p a visitor-specified parameter
     * @return  the result of {@code defaultAction}
     */
    @Override
    public R visitModule(ModuleElement e, P p) {
        return defaultAction(e, p);
    }
}