darcy@575: /*
darcy@851:  * Copyright (c) 2010, 2011, Oracle and/or its affiliates. All rights reserved.
darcy@575:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
darcy@575:  *
darcy@575:  * This code is free software; you can redistribute it and/or modify it
darcy@575:  * under the terms of the GNU General Public License version 2 only, as
darcy@575:  * published by the Free Software Foundation.  Oracle designates this
darcy@575:  * particular file as subject to the "Classpath" exception as provided
darcy@575:  * by Oracle in the LICENSE file that accompanied this code.
darcy@575:  *
darcy@575:  * This code is distributed in the hope that it will be useful, but WITHOUT
darcy@575:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
darcy@575:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
darcy@575:  * version 2 for more details (a copy is included in the LICENSE file that
darcy@575:  * accompanied this code).
darcy@575:  *
darcy@575:  * You should have received a copy of the GNU General Public License version
darcy@575:  * 2 along with this work; if not, write to the Free Software Foundation,
darcy@575:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
darcy@575:  *
darcy@575:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
darcy@575:  * or visit www.oracle.com if you need additional information or have any
darcy@575:  * questions.
darcy@575:  */
darcy@575: 
darcy@575: package javax.lang.model.util;
darcy@575: 
darcy@575: import javax.lang.model.type.*;
darcy@575: import javax.annotation.processing.SupportedSourceVersion;
darcy@575: import static javax.lang.model.element.ElementKind.*;
darcy@575: import static javax.lang.model.SourceVersion.*;
darcy@575: import javax.lang.model.SourceVersion;
darcy@575: 
darcy@575: /**
darcy@575:  * A visitor of types based on their {@linkplain TypeKind kind} with
darcy@575:  * default behavior appropriate for the {@link SourceVersion#RELEASE_7
darcy@575:  * RELEASE_7} source version.  For {@linkplain
darcy@575:  * TypeMirror types} <tt><i>XYZ</i></tt> that may have more than one
darcy@575:  * kind, the <tt>visit<i>XYZ</i></tt> methods in this class delegate
darcy@575:  * to the <tt>visit<i>XYZKind</i></tt> method corresponding to the
darcy@575:  * first argument's kind.  The <tt>visit<i>XYZKind</i></tt> methods
darcy@575:  * call {@link #defaultAction defaultAction}, passing their arguments
darcy@575:  * to {@code defaultAction}'s corresponding parameters.
darcy@575:  *
darcy@575:  * <p> Methods in this class may be overridden subject to their
darcy@575:  * general contract.  Note that annotating methods in concrete
darcy@575:  * subclasses with {@link java.lang.Override @Override} will help
darcy@575:  * ensure that methods are overridden as intended.
darcy@575:  *
darcy@575:  * <p> <b>WARNING:</b> The {@code TypeVisitor} interface implemented
darcy@575:  * by this class may have methods added to it in the future to
darcy@575:  * accommodate new, currently unknown, language structures added to
darcy@575:  * future versions of the Java&trade; programming language.
darcy@575:  * Therefore, methods whose names begin with {@code "visit"} may be
darcy@575:  * added to this class in the future; to avoid incompatibilities,
darcy@575:  * classes which extend this class should not declare any instance
darcy@575:  * methods with names beginning with {@code "visit"}.
darcy@575:  *
darcy@575:  * <p>When such a new visit method is added, the default
darcy@575:  * implementation in this class will be to call the {@link
darcy@575:  * #visitUnknown visitUnknown} method.  A new type kind visitor class
darcy@575:  * will also be introduced to correspond to the new language level;
darcy@575:  * this visitor will have different default behavior for the visit
darcy@575:  * method in question.  When the new visitor is introduced, all or
darcy@575:  * portions of this visitor may be deprecated.
darcy@575:  *
darcy@575:  * @param <R> the return type of this visitor's methods.  Use {@link
darcy@575:  *            Void} for visitors that do not need to return results.
darcy@575:  * @param <P> the type of the additional parameter to this visitor's
darcy@575:  *            methods.  Use {@code Void} for visitors that do not need an
darcy@575:  *            additional parameter.
darcy@575:  *
darcy@575:  * @see TypeKindVisitor6
darcy@575:  * @since 1.7
darcy@575:  */
darcy@575: @SupportedSourceVersion(RELEASE_7)
darcy@575: public class TypeKindVisitor7<R, P> extends TypeKindVisitor6<R, P> {
darcy@575:     /**
darcy@575:      * Constructor for concrete subclasses to call; uses {@code null}
darcy@575:      * for the default value.
darcy@575:      */
darcy@575:     protected TypeKindVisitor7() {
darcy@575:         super(null);
darcy@575:     }
darcy@575: 
darcy@575:     /**
darcy@575:      * Constructor for concrete subclasses to call; uses the argument
darcy@575:      * for the default value.
darcy@575:      *
darcy@575:      * @param defaultValue the value to assign to {@link #DEFAULT_VALUE}
darcy@575:      */
darcy@575:     protected TypeKindVisitor7(R defaultValue) {
darcy@575:         super(defaultValue);
darcy@575:     }
darcy@851: 
darcy@851:     /**
darcy@969:      * This implementation visits a {@code UnionType} by calling
darcy@851:      * {@code defaultAction}.
darcy@851:      *
darcy@851:      * @param t  {@inheritDoc}
darcy@851:      * @param p  {@inheritDoc}
darcy@851:      * @return the result of {@code defaultAction}
darcy@851:      */
darcy@851:     @Override
darcy@969:     public R visitUnion(UnionType t, P p) {
darcy@851:         return defaultAction(t, p);
darcy@851:     }
darcy@575: }