1 /*

     2  * Copyright (c) 2011, 2014, Oracle and/or its affiliates. All rights reserved.

     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.  Oracle designates this

     8  * particular file as subject to the "Classpath" exception as provided

     9  * by Oracle in the LICENSE file that accompanied this code.

    10  *

    11  * This code is distributed in the hope that it will be useful, but WITHOUT

    12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    14  * version 2 for more details (a copy is included in the LICENSE file that

    15  * accompanied this code).

    16  *

    17  * You should have received a copy of the GNU General Public License version

    18  * 2 along with this work; if not, write to the Free Software Foundation,

    19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    20  *

    21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    22  * or visit www.oracle.com if you need additional information or have any

    23  * questions.

    24  */

    25 

    26 package javax.lang.model.util;

    27 

    28 import javax.lang.model.element.*;

    29 import javax.annotation.processing.SupportedSourceVersion;

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

    31 import javax.lang.model.SourceVersion;

    32 

    33 /**

    34  * A visitor of program elements based on their {@linkplain

    35  * ElementKind kind} with default behavior appropriate for the {@link

    36  * SourceVersion#RELEASE_9 RELEASE_9} source version.  For {@linkplain

    37  * Element elements} <tt><i>XYZ</i></tt> that may have more than one

    38  * kind, the <tt>visit<i>XYZ</i></tt> methods in this class delegate

    39  * to the <tt>visit<i>XYZKind</i></tt> method corresponding to the

    40  * first argument's kind.  The <tt>visit<i>XYZKind</i></tt> methods

    41  * call {@link #defaultAction defaultAction}, passing their arguments

    42  * to {@code defaultAction}'s corresponding parameters.

    43  *

    44  * <p> Methods in this class may be overridden subject to their

    45  * general contract.  Note that annotating methods in concrete

    46  * subclasses with {@link java.lang.Override @Override} will help

    47  * ensure that methods are overridden as intended.

    48  *

    49  * <p> <b>WARNING:</b> The {@code ElementVisitor} interface

    50  * implemented by this class may have methods added to it or the

    51  * {@code ElementKind} {@code enum} used in this case may have

    52  * constants added to it in the future to accommodate new, currently

    53  * unknown, language structures added to future versions of the

    54  * Java™ programming language.  Therefore, methods whose names

    55  * begin with {@code "visit"} may be added to this class in the

    56  * future; to avoid incompatibilities, classes which extend this class

    57  * should not declare any instance methods with names beginning with

    58  * {@code "visit"}.

    59  *

    60  * <p>When such a new visit method is added, the default

    61  * implementation in this class will be to call the {@link

    62  * #visitUnknown visitUnknown} method.  A new abstract element kind

    63  * visitor class will also be introduced to correspond to the new

    64  * language level; this visitor will have different default behavior

    65  * for the visit method in question.  When the new visitor is

    66  * introduced, all or portions of this visitor may be deprecated.

    67  *

    68  * @param <R> the return type of this visitor's methods.  Use {@link

    69  *            Void} for visitors that do not need to return results.

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

    71  *            methods.  Use {@code Void} for visitors that do not need an

    72  *            additional parameter.

    73  *

    74  * @see ElementKindVisitor6

    75  * @see ElementKindVisitor7

    76  * @see ElementKindVisitor8

    77  * @since 1.9

    78  */

    79 @SupportedSourceVersion(RELEASE_9)

    80 public class ElementKindVisitor9<R, P> extends ElementKindVisitor8<R, P> {

    81     /**

    82      * Constructor for concrete subclasses; uses {@code null} for the

    83      * default value.

    84      */

    85     protected ElementKindVisitor9() {

    86         super(null);

    87     }

    88 

    89     /**

    90      * Constructor for concrete subclasses; uses the argument for the

    91      * default value.

    92      *

    93      * @param defaultValue the value to assign to {@link #DEFAULT_VALUE}

    94      */

    95     protected ElementKindVisitor9(R defaultValue) {

    96         super(defaultValue);

    97     }

    98 }