1 /*
   2  * Copyright (c) 2011, 2015, 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.annotation.processing.SupportedSourceVersion;
  29 import javax.lang.model.SourceVersion;
  30 import javax.lang.model.element.ModuleElement;
  31 import static javax.lang.model.SourceVersion.*;
  32 
  33 /**
  34  * A simple visitor of program elements with default behavior
  35  * appropriate for the {@link SourceVersion#RELEASE_9 RELEASE_9}
  36  * source version.
  37  *
  38  * Visit methods corresponding to {@code RELEASE_9} and earlier
  39  * language constructs call {@link #defaultAction defaultAction},
  40  * passing their arguments to {@code defaultAction}'s corresponding
  41  * parameters.
  42  *
  43  * <p> Methods in this class may be overridden subject to their
  44  * general contract.  Note that annotating methods in concrete
  45  * subclasses with {@link java.lang.Override @Override} will help
  46  * ensure that methods are overridden as intended.
  47  *
  48  * <p> <b>WARNING:</b> The {@code ElementVisitor} interface
  49  * implemented by this class may have methods added to it in the
  50  * future to accommodate new, currently unknown, language structures
  51  * added to future versions of the Java&trade; programming language.
  52  * Therefore, methods whose names begin with {@code "visit"} may be
  53  * added to this class in the future; to avoid incompatibilities,
  54  * classes which extend this class should not declare any instance
  55  * methods with names beginning with {@code "visit"}.
  56  *
  57  * <p>When such a new visit method is added, the default
  58  * implementation in this class will be to call the {@link
  59  * #visitUnknown visitUnknown} method.  A new simple element visitor
  60  * class will also be introduced to correspond to the new language
  61  * level; this visitor will have different default behavior for the
  62  * visit method in question.  When the new visitor is introduced, all
  63  * or portions of this visitor may be deprecated.
  64  *
  65  * @param <R> the return type of this visitor's methods.  Use {@code Void}
  66  *             for visitors that do not need to return results.
  67  * @param <P> the type of the additional parameter to this visitor's methods.  Use {@code Void}
  68  *              for visitors that do not need an additional parameter.
  69  *
  70  * @see SimpleElementVisitor6
  71  * @see SimpleElementVisitor7
  72  * @see SimpleElementVisitor8
  73  * @since 9
  74  * @spec JPMS
  75  */
  76 @SupportedSourceVersion(RELEASE_9)
  77 public class SimpleElementVisitor9<R, P> extends SimpleElementVisitor8<R, P> {
  78     /**
  79      * Constructor for concrete subclasses; uses {@code null} for the
  80      * default value.
  81      */
  82     protected SimpleElementVisitor9(){
  83         super(null);
  84     }
  85 
  86     /**
  87      * Constructor for concrete subclasses; uses the argument for the
  88      * default value.
  89      *
  90      * @param defaultValue the value to assign to {@link #DEFAULT_VALUE}
  91      */
  92     protected SimpleElementVisitor9(R defaultValue){
  93         super(defaultValue);
  94     }
  95 
  96     /**
  97      * Visits a {@code ModuleElement} by calling {@code
  98      * defaultAction}.
  99      *
 100      * @param e the element to visit
 101      * @param p a visitor-specified parameter
 102      * @return  the result of {@code defaultAction}
 103      */
 104     @Override
 105     public R visitModule(ModuleElement e, P p) {
 106         return defaultAction(e, p);
 107     }
 108 }