aoqi@0: /*
aoqi@0:  * Copyright (c) 2011, 2013, Oracle and/or its affiliates. All rights reserved.
aoqi@0:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
aoqi@0:  *
aoqi@0:  * This code is free software; you can redistribute it and/or modify it
aoqi@0:  * under the terms of the GNU General Public License version 2 only, as
aoqi@0:  * published by the Free Software Foundation.  Oracle designates this
aoqi@0:  * particular file as subject to the "Classpath" exception as provided
aoqi@0:  * by Oracle in the LICENSE file that accompanied this code.
aoqi@0:  *
aoqi@0:  * This code is distributed in the hope that it will be useful, but WITHOUT
aoqi@0:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
aoqi@0:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
aoqi@0:  * version 2 for more details (a copy is included in the LICENSE file that
aoqi@0:  * accompanied this code).
aoqi@0:  *
aoqi@0:  * You should have received a copy of the GNU General Public License version
aoqi@0:  * 2 along with this work; if not, write to the Free Software Foundation,
aoqi@0:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
aoqi@0:  *
aoqi@0:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
aoqi@0:  * or visit www.oracle.com if you need additional information or have any
aoqi@0:  * questions.
aoqi@0:  */
aoqi@0: 
aoqi@0: package javax.lang.model.util;
aoqi@0: 
aoqi@0: import javax.lang.model.element.*;
aoqi@0: import javax.annotation.processing.SupportedSourceVersion;
aoqi@0: import static javax.lang.model.SourceVersion.*;
aoqi@0: import javax.lang.model.SourceVersion;
aoqi@0: 
aoqi@0: /**
aoqi@0:  * A visitor of program elements based on their {@linkplain
aoqi@0:  * ElementKind kind} with default behavior appropriate for the {@link
aoqi@0:  * SourceVersion#RELEASE_8 RELEASE_8} source version.  For {@linkplain
aoqi@0:  * Element elements} <tt><i>XYZ</i></tt> that may have more than one
aoqi@0:  * kind, the <tt>visit<i>XYZ</i></tt> methods in this class delegate
aoqi@0:  * to the <tt>visit<i>XYZKind</i></tt> method corresponding to the
aoqi@0:  * first argument's kind.  The <tt>visit<i>XYZKind</i></tt> methods
aoqi@0:  * call {@link #defaultAction defaultAction}, passing their arguments
aoqi@0:  * to {@code defaultAction}'s corresponding parameters.
aoqi@0:  *
aoqi@0:  * <p> Methods in this class may be overridden subject to their
aoqi@0:  * general contract.  Note that annotating methods in concrete
aoqi@0:  * subclasses with {@link java.lang.Override @Override} will help
aoqi@0:  * ensure that methods are overridden as intended.
aoqi@0:  *
aoqi@0:  * <p> <b>WARNING:</b> The {@code ElementVisitor} interface
aoqi@0:  * implemented by this class may have methods added to it or the
aoqi@0:  * {@code ElementKind} {@code enum} used in this case may have
aoqi@0:  * constants added to it in the future to accommodate new, currently
aoqi@0:  * unknown, language structures added to future versions of the
aoqi@0:  * Java&trade; programming language.  Therefore, methods whose names
aoqi@0:  * begin with {@code "visit"} may be added to this class in the
aoqi@0:  * future; to avoid incompatibilities, classes which extend this class
aoqi@0:  * should not declare any instance methods with names beginning with
aoqi@0:  * {@code "visit"}.
aoqi@0:  *
aoqi@0:  * <p>When such a new visit method is added, the default
aoqi@0:  * implementation in this class will be to call the {@link
aoqi@0:  * #visitUnknown visitUnknown} method.  A new abstract element kind
aoqi@0:  * visitor class will also be introduced to correspond to the new
aoqi@0:  * language level; this visitor will have different default behavior
aoqi@0:  * for the visit method in question.  When the new visitor is
aoqi@0:  * introduced, all or portions of this visitor may be deprecated.
aoqi@0:  *
aoqi@0:  * <p>Note that adding a default implementation of a new visit method
aoqi@0:  * in a visitor class will occur instead of adding a <em>default
aoqi@0:  * method</em> directly in the visitor interface since a Java SE 8
aoqi@0:  * language feature cannot be used to this version of the API since
aoqi@0:  * this version is required to be runnable on Java SE 7
aoqi@0:  * implementations.  Future versions of the API that are only required
aoqi@0:  * to run on Java SE 8 and later may take advantage of default methods
aoqi@0:  * in this situation.
aoqi@0:  *
aoqi@0:  * @param <R> the return type of this visitor's methods.  Use {@link
aoqi@0:  *            Void} for visitors that do not need to return results.
aoqi@0:  * @param <P> the type of the additional parameter to this visitor's
aoqi@0:  *            methods.  Use {@code Void} for visitors that do not need an
aoqi@0:  *            additional parameter.
aoqi@0:  *
aoqi@0:  * @see ElementKindVisitor6
aoqi@0:  * @see ElementKindVisitor7
aoqi@0:  * @since 1.8
aoqi@0:  */
aoqi@0: @SupportedSourceVersion(RELEASE_8)
aoqi@0: public class ElementKindVisitor8<R, P> extends ElementKindVisitor7<R, P> {
aoqi@0:     /**
aoqi@0:      * Constructor for concrete subclasses; uses {@code null} for the
aoqi@0:      * default value.
aoqi@0:      */
aoqi@0:     protected ElementKindVisitor8() {
aoqi@0:         super(null);
aoqi@0:     }
aoqi@0: 
aoqi@0:     /**
aoqi@0:      * Constructor for concrete subclasses; uses the argument for the
aoqi@0:      * default value.
aoqi@0:      *
aoqi@0:      * @param defaultValue the value to assign to {@link #DEFAULT_VALUE}
aoqi@0:      */
aoqi@0:     protected ElementKindVisitor8(R defaultValue) {
aoqi@0:         super(defaultValue);
aoqi@0:     }
aoqi@0: }