/*
 * Copyright (c) 2011, 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
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package javax.lang.model.util;

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

/**
 * A visitor of types based on their {@linkplain TypeKind kind} with
 * default behavior appropriate for the {@link SourceVersion#RELEASE_8
 * RELEASE_8} source version.  For {@linkplain
 * TypeMirror types} <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 TypeVisitor} 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&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 type 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 TypeKindVisitor6
 * @see TypeKindVisitor7
 * @since 1.8
 */
@SupportedSourceVersion(RELEASE_8)
public class TypeKindVisitor8<R, P> extends TypeKindVisitor7<R, P> {
    /**
     * Constructor for concrete subclasses to call; uses {@code null}
     * for the default value.
     */
    protected TypeKindVisitor8() {
        super(null);
    }

    /**
     * Constructor for concrete subclasses to call; uses the argument
     * for the default value.
     *
     * @param defaultValue the value to assign to {@link #DEFAULT_VALUE}
     */
    protected TypeKindVisitor8(R defaultValue) {
        super(defaultValue);
    }

    /**
     * This implementation visits an {@code IntersectionType} by calling
     * {@code defaultAction}.
     *
     * @param t  {@inheritDoc}
     * @param p  {@inheritDoc}
     * @return the result of {@code defaultAction}
     */
    @Override
    public R visitIntersection(IntersectionType t, P p) {
        return defaultAction(t, p);
    }
}
