Java example source code file (AbstractAnnotationValueVisitor6.java)

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abstractannotationvaluevisitor6, supportedsourceversion, unknownannotationvalueexception

The AbstractAnnotationValueVisitor6.java Java example source code

/*
 * Copyright (c) 2005, 2013, 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> WARNING: 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.
 *
 * <p>Note that adding a default implementation of a new visit method
 * in a visitor class will occur instead of adding a <em>default
 * method</em> directly in the visitor interface since a Java SE 8
 * language feature cannot be used to this version of the API since
 * this version is required to be runnable on Java SE 7
 * implementations.  Future versions of the API that are only required
 * to run on Java SE 8 and later may take advantage of default methods
 * in this situation.
 *
 * @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
 * @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}
     *
     * <p>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}
     */
    public R visitUnknown(AnnotationValue av, P p) {
        throw new UnknownAnnotationValueException(av, p);
    }
}