1 /*
   2  * Copyright (c) 2005, 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.type.*;
  29 import javax.annotation.processing.SupportedSourceVersion;
  30 import javax.lang.model.SourceVersion;
  31 import static javax.lang.model.SourceVersion.*;
  32 
  33 
  34 /**
  35  * A simple visitor of types with default behavior appropriate for the
  36  * {@link SourceVersion#RELEASE_6 RELEASE_6} source version.
  37  *
  38  * Visit methods corresponding to {@code RELEASE_6} language
  39  * constructs call {@link #defaultAction defaultAction}, passing their
  40  * arguments to {@code defaultAction}'s corresponding parameters.
  41  *
  42  * For constructs introduced in {@code RELEASE_7} and later, {@code
  43  * visitUnknown} is called instead.
  44  *
  45  * <p> Methods in this class may be overridden subject to their
  46  * general contract.  Note that annotating methods in concrete
  47  * subclasses with {@link java.lang.Override @Override} will help
  48  * ensure that methods are overridden as intended.
  49  *
  50  * <p> <b>WARNING:</b> The {@code TypeVisitor} interface implemented
  51  * by this class may have methods added to it in the future to
  52  * accommodate new, currently unknown, language structures added to
  53  * future versions of the Java&trade; programming language.
  54  * Therefore, methods whose names begin with {@code "visit"} may be
  55  * added to this class in the future; to avoid incompatibilities,
  56  * classes which extend this class should not declare any instance
  57  * methods with names beginning with {@code "visit"}.
  58  *
  59  * <p>When such a new visit method is added, the default
  60  * implementation in this class will be to call the {@link
  61  * #visitUnknown visitUnknown} method.  A new simple type visitor
  62  * class will also be introduced to correspond to the new language
  63  * level; this visitor will have different default behavior for the
  64  * visit method in question.  When the new visitor is introduced, all
  65  * or portions of this visitor may be deprecated.
  66  *
  67  * <p>Note that adding a default implementation of a new visit method
  68  * in a visitor class will occur instead of adding a <em>default
  69  * method</em> directly in the visitor interface since a Java SE 8
  70  * language feature cannot be used to this version of the API since
  71  * this version is required to be runnable on Java SE 7
  72  * implementations.  Future versions of the API that are only required
  73  * to run on Java SE 8 and later may take advantage of default methods
  74  * in this situation.
  75  *
  76  * @param <R> the return type of this visitor's methods.  Use {@link
  77  *            Void} for visitors that do not need to return results.
  78  * @param <P> the type of the additional parameter to this visitor's
  79  *            methods.  Use {@code Void} for visitors that do not need an
  80  *            additional parameter.
  81  *
  82  * @author Joseph D. Darcy
  83  * @author Scott Seligman
  84  * @author Peter von der Ah&eacute;
  85  *
  86  * @see SimpleTypeVisitor7
  87  * @see SimpleTypeVisitor8
  88  * @see SimpleTypeVisitor9
  89  * @since 1.6
  90  * @deprecated Release 6 is obsolete; update to a visitor for a newer
  91  * release level.
  92  */
  93 @Deprecated
  94 @SupportedSourceVersion(RELEASE_6)
  95 public class SimpleTypeVisitor6<R, P> extends AbstractTypeVisitor6<R, P> {
  96     /**
  97      * Default value to be returned; {@link #defaultAction
  98      * defaultAction} returns this value unless the method is
  99      * overridden.
 100      */
 101     protected final R DEFAULT_VALUE;
 102 
 103     /**
 104      * Constructor for concrete subclasses; uses {@code null} for the
 105      * default value.
 106      */
 107     protected SimpleTypeVisitor6(){
 108         DEFAULT_VALUE = null;
 109     }
 110 
 111     /**
 112      * Constructor for concrete subclasses; uses the argument for the
 113      * default value.
 114      *
 115      * @param defaultValue the value to assign to {@link #DEFAULT_VALUE}
 116      */
 117     protected SimpleTypeVisitor6(R defaultValue){
 118         DEFAULT_VALUE = defaultValue;
 119     }
 120 
 121     /**
 122      * The default action for visit methods.  The implementation in
 123      * this class just returns {@link #DEFAULT_VALUE}; subclasses will
 124      * commonly override this method.
 125      *
 126      * @param e the type to process
 127      * @param p a visitor-specified parameter
 128      * @return {@code DEFAULT_VALUE} unless overridden
 129      */
 130     protected R defaultAction(TypeMirror e, P p) {
 131         return DEFAULT_VALUE;
 132     }
 133 
 134     /**
 135      * {@inheritDoc} This implementation calls {@code defaultAction}.
 136      *
 137      * @param t {@inheritDoc}
 138      * @param p {@inheritDoc}
 139      * @return  the result of {@code defaultAction}
 140      */
 141     public R visitPrimitive(PrimitiveType t, P p) {
 142         return defaultAction(t, p);
 143     }
 144 
 145     /**
 146      * {@inheritDoc} This implementation calls {@code defaultAction}.
 147      *
 148      * @param t {@inheritDoc}
 149      * @param p {@inheritDoc}
 150      * @return  the result of {@code defaultAction}
 151      */
 152     public R visitNull(NullType t, P p){
 153         return defaultAction(t, p);
 154     }
 155 
 156     /**
 157      * {@inheritDoc} This implementation calls {@code defaultAction}.
 158      *
 159      * @param t {@inheritDoc}
 160      * @param p {@inheritDoc}
 161      * @return  the result of {@code defaultAction}
 162      */
 163     public R visitArray(ArrayType t, P p){
 164         return defaultAction(t, p);
 165     }
 166 
 167     /**
 168      * {@inheritDoc} This implementation calls {@code defaultAction}.
 169      *
 170      * @param t {@inheritDoc}
 171      * @param p {@inheritDoc}
 172      * @return  the result of {@code defaultAction}
 173      */
 174     public R visitDeclared(DeclaredType t, P p){
 175         return defaultAction(t, p);
 176     }
 177 
 178     /**
 179      * {@inheritDoc} This implementation calls {@code defaultAction}.
 180      *
 181      * @param t {@inheritDoc}
 182      * @param p {@inheritDoc}
 183      * @return  the result of {@code defaultAction}
 184      */
 185     public R visitError(ErrorType t, P p){
 186         return defaultAction(t, p);
 187     }
 188 
 189     /**
 190      * {@inheritDoc} This implementation calls {@code defaultAction}.
 191      *
 192      * @param t {@inheritDoc}
 193      * @param p {@inheritDoc}
 194      * @return  the result of {@code defaultAction}
 195      */
 196     public R visitTypeVariable(TypeVariable t, P p){
 197         return defaultAction(t, p);
 198     }
 199 
 200     /**
 201      * {@inheritDoc} This implementation calls {@code defaultAction}.
 202      *
 203      * @param t {@inheritDoc}
 204      * @param p {@inheritDoc}
 205      * @return  the result of {@code defaultAction}
 206      */
 207     public R visitWildcard(WildcardType t, P p){
 208         return defaultAction(t, p);
 209     }
 210 
 211     /**
 212      * {@inheritDoc} This implementation calls {@code defaultAction}.
 213      *
 214      * @param t {@inheritDoc}
 215      * @param p {@inheritDoc}
 216      * @return  the result of {@code defaultAction}
 217      */
 218     public R visitExecutable(ExecutableType t, P p) {
 219         return defaultAction(t, p);
 220     }
 221 
 222     /**
 223      * {@inheritDoc} This implementation calls {@code defaultAction}.
 224      *
 225      * @param t {@inheritDoc}
 226      * @param p {@inheritDoc}
 227      * @return  the result of {@code defaultAction}
 228      */
 229     public R visitNoType(NoType t, P p){
 230         return defaultAction(t, p);
 231     }
 232 }