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 * Copyright (c) 2005, 2017, 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

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package javax.lang.model.util;

import javax.lang.model.element.*;

import static javax.lang.model.SourceVersion.*;

import javax.lang.model.SourceVersion;

import javax.annotation.processing.SupportedSourceVersion;

/**

 * A skeletal visitor for annotation values with default behavior

 * appropriate for the {@link SourceVersion#RELEASE_6 RELEASE_6}

 * source version.

 *

 * <p> <b>WARNING:</b> The {@code AnnotationValueVisitor} 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"}.

 *

 * <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 annotation

 * value 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

 * @param <P> the type of the additional parameter to this visitor's methods.

 *

 * @author Joseph D. Darcy

 * @author Scott Seligman

 * @author Peter von der Ahé

 *

 * @see AbstractAnnotationValueVisitor7

 * @see AbstractAnnotationValueVisitor8

 * @see AbstractAnnotationValueVisitor9

 * @since 1.6

 */

@SupportedSourceVersion(RELEASE_6)

public abstract class AbstractAnnotationValueVisitor6<R, P>

    implements AnnotationValueVisitor<R, P> {

    /**

     * Constructor for concrete subclasses to call.

     */

    protected AbstractAnnotationValueVisitor6() {}

    /**

     * Visits an annotation value as if by passing itself to that

     * value's {@link AnnotationValue#accept accept}.  The invocation

     * {@code v.visit(av)} is equivalent to {@code av.accept(v, p)}.

     * @param av {@inheritDoc}

     * @param p  {@inheritDoc}

     */

    public final R visit(AnnotationValue av, P p) {

        return av.accept(this, p);

    }

    /**

     * Visits an annotation value as if by passing itself to that

     * value's {@link AnnotationValue#accept accept} method passing

     * {@code null} for the additional parameter.  The invocation

     * {@code v.visit(av)} is equivalent to {@code av.accept(v,

     * null)}.

     * @param av {@inheritDoc}

     */

    public final R visit(AnnotationValue av) {

        return av.accept(this, null);

    }

    /**

     * {@inheritDoc}

     *

     * @implSpec The default implementation of this method in {@code

     * AbstractAnnotationValueVisitor6} will always throw {@code

     * UnknownAnnotationValueException}.  This behavior is not

     * required of a subclass.

     *

     * @param av {@inheritDoc}

     * @param p  {@inheritDoc}

     */

    @Override

    public R visitUnknown(AnnotationValue av, P p) {

        throw new UnknownAnnotationValueException(av, p);

    }

}