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  */
  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}, passing their arguments to
  40  * {@code defaultAction}'s corresponding parameters.
  41  *
  42  * <p> Methods in this class may be overridden subject to their
  43  * general contract.  Note that annotating methods in concrete
  44  * subclasses with {@link java.lang.Override @Override} will help
  45  * ensure that methods are overridden as intended.
  46  *
  47  * <p> <b>WARNING:</b> The {@code TypeVisitor} interface implemented
  48  * by this class may have methods added to it in the future to
  49  * accommodate new, currently unknown, language structures added to
  50  * future versions of the Java&trade; programming language.
  51  * Therefore, methods whose names begin with {@code "visit"} may be
  52  * added to this class in the future; to avoid incompatibilities,
  53  * classes which extend this class should not declare any instance
  54  * methods with names beginning with {@code "visit"}.
  55  *
  56  * <p>When such a new visit method is added, the default
  57  * implementation in this class will be to call the {@link
  58  * #visitUnknown visitUnknown} method.  A new simple type visitor
  59  * class will also be introduced to correspond to the new language
  60  * level; this visitor will have different default behavior for the
  61  * visit method in question.  When the new visitor is introduced, all
  62  * or portions of this visitor may be deprecated.
  63  *
  64  * @param <R> the return type of this visitor's methods.  Use {@link
  65  *            Void} for visitors that do not need to return results.
  66  * @param <P> the type of the additional parameter to this visitor's
  67  *            methods.  Use {@code Void} for visitors that do not need an
  68  *            additional parameter.
  69  *
  70  * @author Joseph D. Darcy
  71  * @author Scott Seligman
  72  * @author Peter von der Ah&eacute;
  73  * @since 1.6
  74  */
  75 @SupportedSourceVersion(RELEASE_6)
  76 public class SimpleTypeVisitor6<R, P> extends AbstractTypeVisitor6<R, P> {
  77     /**
  78      * Default value to be returned; {@link #defaultAction
  79      * defaultAction} returns this value unless the method is
  80      * overridden.
  81      */
  82     protected final R DEFAULT_VALUE;
  83 
  84     /**
  85      * Constructor for concrete subclasses; uses {@code null} for the
  86      * default value.
  87      */
  88     protected SimpleTypeVisitor6(){
  89         DEFAULT_VALUE = null;
  90     }
  91 
  92     /**
  93      * Constructor for concrete subclasses; uses the argument for the
  94      * default value.
  95      *
  96      * @param defaultValue the value to assign to {@link #DEFAULT_VALUE}
  97      */
  98     protected SimpleTypeVisitor6(R defaultValue){
  99         DEFAULT_VALUE = defaultValue;
 100     }
 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     protected R defaultAction(TypeMirror e, P p) {
 108         return DEFAULT_VALUE;
 109     }
 110 
 111     /**
 112      * {@inheritDoc} This implementation calls {@code defaultAction}.
 113      *
 114      * @param t {@inheritDoc}
 115      * @param p {@inheritDoc}
 116      * @return  the result of {@code defaultAction}
 117      */
 118     public R visitPrimitive(PrimitiveType t, P p) {
 119         return defaultAction(t, p);
 120     }
 121 
 122     /**
 123      * {@inheritDoc} This implementation calls {@code defaultAction}.
 124      *
 125      * @param t {@inheritDoc}
 126      * @param p {@inheritDoc}
 127      * @return  the result of {@code defaultAction}
 128      */
 129     public R visitNull(NullType t, P p){
 130         return defaultAction(t, p);
 131     }
 132 
 133     /**
 134      * {@inheritDoc} This implementation calls {@code defaultAction}.
 135      *
 136      * @param t {@inheritDoc}
 137      * @param p {@inheritDoc}
 138      * @return  the result of {@code defaultAction}
 139      */
 140     public R visitArray(ArrayType t, P p){
 141         return defaultAction(t, p);
 142     }
 143 
 144     /**
 145      * {@inheritDoc} This implementation calls {@code defaultAction}.
 146      *
 147      * @param t {@inheritDoc}
 148      * @param p {@inheritDoc}
 149      * @return  the result of {@code defaultAction}
 150      */
 151     public R visitDeclared(DeclaredType t, P p){
 152         return defaultAction(t, p);
 153     }
 154 
 155     /**
 156      * {@inheritDoc} This implementation calls {@code defaultAction}.
 157      *
 158      * @param t {@inheritDoc}
 159      * @param p {@inheritDoc}
 160      * @return  the result of {@code defaultAction}
 161      */
 162     public R visitError(ErrorType t, P p){
 163         return defaultAction(t, p);
 164     }
 165 
 166     /**
 167      * {@inheritDoc} This implementation calls {@code defaultAction}.
 168      *
 169      * @param t {@inheritDoc}
 170      * @param p {@inheritDoc}
 171      * @return  the result of {@code defaultAction}
 172      */
 173     public R visitTypeVariable(TypeVariable t, P p){
 174         return defaultAction(t, p);
 175     }
 176 
 177     /**
 178      * {@inheritDoc} This implementation calls {@code defaultAction}.
 179      *
 180      * @param t {@inheritDoc}
 181      * @param p {@inheritDoc}
 182      * @return  the result of {@code defaultAction}
 183      */
 184     public R visitWildcard(WildcardType t, P p){
 185         return defaultAction(t, p);
 186     }
 187 
 188     /**
 189      * {@inheritDoc} This implementation calls {@code defaultAction}.
 190      *
 191      * @param t {@inheritDoc}
 192      * @param p {@inheritDoc}
 193      * @return  the result of {@code defaultAction}
 194      */
 195     public R visitExecutable(ExecutableType t, P p) {
 196         return defaultAction(t, p);
 197     }
 198 
 199     /**
 200      * {@inheritDoc} This implementation calls {@code defaultAction}.
 201      *
 202      * @param t {@inheritDoc}
 203      * @param p {@inheritDoc}
 204      * @return  the result of {@code defaultAction}
 205      */
 206     public R visitNoType(NoType t, P p){
 207         return defaultAction(t, p);
 208     }
 209 }