1 /*
   2  * Copyright (c) 2010, 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 javax.lang.model.SourceVersion;
  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_7 RELEASE_7}
  36  * source version.
  37  *
  38  * Visit methods corresponding to {@code RELEASE_7} 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  * <p>Note that adding a default implementation of a new visit method
  66  * in a visitor class will occur instead of adding a <em>default
  67  * method</em> directly in the visitor interface since a Java SE 8
  68  * language feature cannot be used to this version of the API since
  69  * this version is required to be runnable on Java SE 7
  70  * implementations.  Future versions of the API that are only required
  71  * to run on Java SE 8 and later may take advantage of default methods
  72  * in this situation.
  73  *
  74  * @param <R> the return type of this visitor's methods.  Use {@code Void}
  75  *             for visitors that do not need to return results.
  76  * @param <P> the type of the additional parameter to this visitor's methods.  Use {@code Void}
  77  *              for visitors that do not need an additional parameter.
  78  *
  79  * @see SimpleElementVisitor6
  80  * @see SimpleElementVisitor8
  81  * @see SimpleElementVisitor9
  82  * @since 1.7
  83  */
  84 @SupportedSourceVersion(RELEASE_7)
  85 public class SimpleElementVisitor7<R, P> extends SimpleElementVisitor6<R, P> {
  86     /**
  87      * Constructor for concrete subclasses; uses {@code null} for the
  88      * default value.
  89      */
  90     @SuppressWarnings("deprecation") // Superclass constructor deprecated
  91     protected SimpleElementVisitor7(){
  92         super(null);
  93     }
  94 
  95     /**
  96      * Constructor for concrete subclasses; uses the argument for the
  97      * default value.
  98      *
  99      * @param defaultValue the value to assign to {@link #DEFAULT_VALUE}
 100      */
 101     @SuppressWarnings("deprecation") // Superclass constructor deprecated
 102     protected SimpleElementVisitor7(R defaultValue){
 103         super(defaultValue);
 104     }
 105 
 106     /**
 107      * This implementation calls {@code defaultAction}.
 108      *
 109      * @param e {@inheritDoc}
 110      * @param p {@inheritDoc}
 111      * @return  the result of {@code defaultAction}
 112      */
 113     @Override
 114     public R visitVariable(VariableElement e, P p) {
 115         return defaultAction(e, p);
 116     }
 117 }