jdk8-mips64-public/langtools: src/share/classes/javax/lang/model/util/SimpleElementVisitor6.java@9a66ca7c79fa

     1 /*

     2  * Copyright 2005-2006 Sun Microsystems, Inc.  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.  Sun designates this

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

     9  * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

    22  * CA 95054 USA or visit www.sun.com if you need additional information or

    23  * have any questions.

    24  */

    26 package javax.lang.model.util;

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

    29 import javax.annotation.processing.SupportedSourceVersion;

    30 import static javax.lang.model.element.ElementKind.*;

    31 import javax.lang.model.SourceVersion;

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

    35 /**

    36  * A simple visitor of program elements with default behavior

    37  * appropriate for the {@link SourceVersion#RELEASE_6 RELEASE_6}

    38  * source version.

    39  *

    40  * Visit methods corresponding to {@code RELEASE_6} language

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

    42  * {@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 in the

    51  * future to accommodate new, currently unknown, language structures

    52  * added to future versions of the Java&trade; programming language.

    53  * Therefore, methods whose names begin with {@code "visit"} may be

    54  * added to this class in the future; to avoid incompatibilities,

    55  * classes which extend this class should not declare any instance

    56  * methods with names beginning with {@code "visit"}.

    57  *

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

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

    60  * #visitUnknown visitUnknown} method.  A new simple element visitor

    61  * class will also be introduced to correspond to the new language

    62  * level; this visitor will have different default behavior for the

    63  * visit method in question.  When the new visitor is introduced, all

    64  * or portions of this visitor may be deprecated.

    65  *

    66  * @param <R> the return type of this visitor's methods.  Use {@code Void}

    67  *             for visitors that do not need to return results.

    68  * @param <P> the type of the additional parameter to this visitor's methods.  Use {@code Void}

    69  *              for visitors that do not need an additional parameter.

    70  *

    71  * @author Joseph D. Darcy

    72  * @author Scott Seligman

    73  * @author Peter von der Ah&eacute;

    74  * @since 1.6

    75  */

    76 @SupportedSourceVersion(RELEASE_6)

    77 public class SimpleElementVisitor6<R, P> extends AbstractElementVisitor6<R, P> {

    78     /**

    79      * Default value to be returned; {@link #defaultAction

    80      * defaultAction} returns this value unless the method is

    81      * overridden.

    82      */

    83     protected final R DEFAULT_VALUE;

    85     /**

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

    87      * default value.

    88      */

    89     protected SimpleElementVisitor6(){

    90         DEFAULT_VALUE = null;

    91     }

    93     /**

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

    95      * default value.

    96      *

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

    98      */

    99     protected SimpleElementVisitor6(R defaultValue){

   100         DEFAULT_VALUE = defaultValue;

   101     }

   102     /**

   103      * The default action for visit methods.  The implementation in

   104      * this class just returns {@link #DEFAULT_VALUE}; subclasses will

   105      * commonly override this method.

   106      *

   107      * @param e the element to process

   108      * @param p a visitor-specified parameter

   109      * @return {@code DEFAULT_VALUE} unless overridden

   110      */

   111     protected R defaultAction(Element e, P p) {

   112         return DEFAULT_VALUE;

   113     }

   115     /**

   116      * {@inheritDoc} This implementation calls {@code defaultAction}.

   117      *

   118      * @param e {@inheritDoc}

   119      * @param p {@inheritDoc}

   120      * @return  the result of {@code defaultAction}

   121      */

   122     public R visitPackage(PackageElement e, P p) {

   123         return defaultAction(e, p);

   124     }

   126     /**

   127      * {@inheritDoc} This implementation calls {@code defaultAction}.

   128      *

   129      * @param e {@inheritDoc}

   130      * @param p {@inheritDoc}

   131      * @return  the result of {@code defaultAction}

   132      */

   133     public R visitType(TypeElement e, P p) {

   134         return defaultAction(e, p);

   135     }

   137     /**

   138      * {@inheritDoc} This implementation calls {@code defaultAction}.

   139      *

   140      * @param e {@inheritDoc}

   141      * @param p {@inheritDoc}

   142      * @return  the result of {@code defaultAction}

   143      */

   144     public R visitVariable(VariableElement e, P p) {

   145         return defaultAction(e, p);

   146     }

   148     /**

   149      * {@inheritDoc} This implementation calls {@code defaultAction}.

   150      *

   151      * @param e {@inheritDoc}

   152      * @param p {@inheritDoc}

   153      * @return  the result of {@code defaultAction}

   154      */

   155     public R visitExecutable(ExecutableElement e, P p) {

   156         return defaultAction(e, p);

   157     }

   159     /**

   160      * {@inheritDoc} This implementation calls {@code defaultAction}.

   161      *

   162      * @param e {@inheritDoc}

   163      * @param p {@inheritDoc}

   164      * @return  the result of {@code defaultAction}

   165      */

   166     public R visitTypeParameter(TypeParameterElement e, P p) {

   167         return defaultAction(e, p);

   168     }

   169 }

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