/*

 * Copyright (c) 2011, 2014, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

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 {@linkplain

 * ElementKind kind} with default behavior appropriate for the {@link

 * SourceVersion#RELEASE_9 RELEASE_9} source version.  For {@linkplain

 * Element elements} <tt><i>XYZ</i></tt> that may have more than one

 * kind, the <tt>visit<i>XYZ</i></tt> methods in this class delegate

 * to the <tt>visit<i>XYZKind</i></tt> method corresponding to the

 * first argument's kind.  The <tt>visit<i>XYZKind</i></tt> 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™ 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 1.9

 */

@SupportedSourceVersion(RELEASE_9)

public class ElementKindVisitor9<R, P> extends ElementKindVisitor8<R, P> {

    /**

     * 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.

     *

     * @param defaultValue the value to assign to {@link #DEFAULT_VALUE}

     */

    protected ElementKindVisitor9(R defaultValue) {

        super(defaultValue);

    }

}