jdk8-mips64-public/langtools: src/share/classes/javax/lang/model/util/SimpleElementVisitor6.java@c75be5bc5283

     1 /*

     2  * Copyright (c) 2005, 2012, 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  */

    26 package javax.lang.model.util;

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

    29 import javax.annotation.processing.SupportedSourceVersion;

    30 import javax.lang.model.SourceVersion;

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

    34 /**

    35  * A simple visitor of program elements with default behavior

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

    37  * source version.

    38  *

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

    40  * constructs call {@link #defaultAction defaultAction}, passing their

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

    42  *

    43  * For constructs introduced in {@code RELEASE_7} and later, {@code

    44  * visitUnknown} is called instead.

    45  *

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

    47  * general contract.  Note that annotating methods in concrete

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

    49  * ensure that methods are overridden as intended.

    50  *

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

    52  * implemented by this class may have methods added to it in the

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

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

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

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

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

    58  * methods with names beginning with {@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 simple element visitor

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

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

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

    66  * or portions of this visitor may be deprecated.

    67  *

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

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

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

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

    72  *

    73  * @author Joseph D. Darcy

    74  * @author Scott Seligman

    75  * @author Peter von der Ah&eacute;

    76  *

    77  * @see SimpleElementVisitor7

    78  * @see SimpleElementVisitor8

    79  * @since 1.6

    80  */

    81 @SupportedSourceVersion(RELEASE_6)

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

    83     /**

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

    85      * defaultAction} returns this value unless the method is

    86      * overridden.

    87      */

    88     protected final R DEFAULT_VALUE;

    90     /**

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

    92      * default value.

    93      */

    94     protected SimpleElementVisitor6(){

    95         DEFAULT_VALUE = null;

    96     }

    98     /**

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

   100      * default value.

   101      *

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

   103      */

   104     protected SimpleElementVisitor6(R defaultValue){

   105         DEFAULT_VALUE = defaultValue;

   106     }

   107     /**

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

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

   110      * commonly override this method.

   111      *

   112      * @param e the element to process

   113      * @param p a visitor-specified parameter

   114      * @return {@code DEFAULT_VALUE} unless overridden

   115      */

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

   117         return DEFAULT_VALUE;

   118     }

   120     /**

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

   122      *

   123      * @param e {@inheritDoc}

   124      * @param p {@inheritDoc}

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

   126      */

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

   128         return defaultAction(e, p);

   129     }

   131     /**

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

   133      *

   134      * @param e {@inheritDoc}

   135      * @param p {@inheritDoc}

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

   137      */

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

   139         return defaultAction(e, p);

   140     }

   142     /**

   143      * {@inheritDoc}

   144      *

   145      * This implementation calls {@code defaultAction}, unless the

   146      * element is a {@code RESOURCE_VARIABLE} in which case {@code

   147      * visitUnknown} is called.

   148      *

   149      * @param e {@inheritDoc}

   150      * @param p {@inheritDoc}

   151      * @return  the result of {@code defaultAction} or {@code visitUnknown}

   152      */

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

   154         if (e.getKind() != ElementKind.RESOURCE_VARIABLE)

   155             return defaultAction(e, p);

   156         else

   157             return visitUnknown(e, p);

   158     }

   160     /**

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

   162      *

   163      * @param e {@inheritDoc}

   164      * @param p {@inheritDoc}

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

   166      */

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

   168         return defaultAction(e, p);

   169     }

   171     /**

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

   173      *

   174      * @param e {@inheritDoc}

   175      * @param p {@inheritDoc}

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

   177      */

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

   179         return defaultAction(e, p);

   180     }

   181 }

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