1 /*
   2  * Copyright (c) 2005, 2013, 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 
  29 import java.util.List;
  30 import javax.lang.model.element.*;
  31 
  32 import javax.lang.model.type.TypeMirror;
  33 import static javax.lang.model.SourceVersion.*;
  34 import javax.lang.model.SourceVersion;
  35 import javax.annotation.processing.SupportedSourceVersion;
  36 
  37 /**
  38  * A simple visitor for annotation values with default behavior
  39  * appropriate for the {@link SourceVersion#RELEASE_6 RELEASE_6}
  40  * source version.  Visit methods call {@link
  41  * #defaultAction} passing their arguments to {@code defaultAction}'s
  42  * corresponding parameters.
  43  *
  44  * <p> Methods in this class may be overridden subject to their
  45  * general contract.  Note that annotating methods in concrete
  46  * subclasses with {@link java.lang.Override @Override} will help
  47  * ensure that methods are overridden as intended.
  48  *
  49  * <p> <b>WARNING:</b> The {@code AnnotationValueVisitor} interface
  50  * implemented by this class may have methods added to it in the
  51  * future to accommodate new, currently unknown, language structures
  52  * added to future versions of the Java&trade; programming language.
  53  * Therefore, methods whose names begin with {@code "visit"} may be
  54  * added to this class in the future; to avoid incompatibilities,
  55  * classes which extend this class should not declare any instance
  56  * methods with names beginning with {@code "visit"}.
  57  *
  58  * <p>When such a new visit method is added, the default
  59  * implementation in this class will be to call the {@link
  60  * #visitUnknown visitUnknown} method.  A new simple annotation
  61  * value visitor class will also be introduced to correspond to the
  62  * new language level; this visitor will have different default
  63  * behavior for the visit method in question.  When the new visitor is
  64  * introduced, all or portions of this visitor may be deprecated.
  65  *
  66  * <p>Note that adding a default implementation of a new visit method
  67  * in a visitor class will occur instead of adding a <em>default
  68  * method</em> directly in the visitor interface since a Java SE 8
  69  * language feature cannot be used to this version of the API since
  70  * this version is required to be runnable on Java SE 7
  71  * implementations.  Future versions of the API that are only required
  72  * to run on Java SE 8 and later may take advantage of default methods
  73  * in this situation.
  74  *
  75  * @param <R> the return type of this visitor's methods
  76  * @param <P> the type of the additional parameter to this visitor's methods.
  77  *
  78  * @author Joseph D. Darcy
  79  * @author Scott Seligman
  80  * @author Peter von der Ah&eacute;
  81  *
  82  * @see SimpleAnnotationValueVisitor7
  83  * @see SimpleAnnotationValueVisitor8
  84  * @since 1.6
  85  */
  86 @SupportedSourceVersion(RELEASE_6)
  87 public class SimpleAnnotationValueVisitor6<R, P>
  88     extends AbstractAnnotationValueVisitor6<R, P> {
  89 
  90     /**
  91      * Default value to be returned; {@link #defaultAction
  92      * defaultAction} returns this value unless the method is
  93      * overridden.
  94      */
  95     protected final R DEFAULT_VALUE;
  96 
  97     /**
  98      * Constructor for concrete subclasses; uses {@code null} for the
  99      * default value.
 100      */
 101     protected SimpleAnnotationValueVisitor6() {
 102         super();
 103         DEFAULT_VALUE = null;
 104     }
 105 
 106     /**
 107      * Constructor for concrete subclasses; uses the argument for the
 108      * default value.
 109      *
 110      * @param defaultValue the value to assign to {@link #DEFAULT_VALUE}
 111      */
 112     protected SimpleAnnotationValueVisitor6(R defaultValue) {
 113         super();
 114         DEFAULT_VALUE = defaultValue;
 115     }
 116 
 117     /**
 118      * The default action for visit methods.  The implementation in
 119      * this class just returns {@link #DEFAULT_VALUE}; subclasses will
 120      * commonly override this method.
 121      *
 122      * @param o the value of the annotation
 123      * @param p a visitor-specified parameter
 124      * @return {@code DEFAULT_VALUE} unless overridden
 125      */
 126     protected R defaultAction(Object o, P p) {
 127         return DEFAULT_VALUE;
 128     }
 129 
 130     /**
 131      * {@inheritDoc} This implementation calls {@code defaultAction}.
 132      *
 133      * @param b {@inheritDoc}
 134      * @param p {@inheritDoc}
 135      * @return  the result of {@code defaultAction}
 136      */
 137     public R visitBoolean(boolean b, P p) {
 138         return defaultAction(b, p);
 139     }
 140 
 141     /**
 142      * {@inheritDoc} This implementation calls {@code defaultAction}.
 143      *
 144      * @param b {@inheritDoc}
 145      * @param p {@inheritDoc}
 146      * @return  the result of {@code defaultAction}
 147      */
 148     public R visitByte(byte b, P p) {
 149         return defaultAction(b, p);
 150     }
 151 
 152     /**
 153      * {@inheritDoc} This implementation calls {@code defaultAction}.
 154      *
 155      * @param c {@inheritDoc}
 156      * @param p {@inheritDoc}
 157      * @return  the result of {@code defaultAction}
 158      */
 159     public R visitChar(char c, P p) {
 160         return defaultAction(c, p);
 161     }
 162 
 163     /**
 164      * {@inheritDoc} This implementation calls {@code defaultAction}.
 165      *
 166      * @param d {@inheritDoc}
 167      * @param p {@inheritDoc}
 168      * @return  the result of {@code defaultAction}
 169      */
 170     public R visitDouble(double d, P p) {
 171         return defaultAction(d, p);
 172     }
 173 
 174     /**
 175      * {@inheritDoc} This implementation calls {@code defaultAction}.
 176      *
 177      * @param f {@inheritDoc}
 178      * @param p {@inheritDoc}
 179      * @return  the result of {@code defaultAction}
 180      */
 181     public R visitFloat(float f, P p) {
 182         return defaultAction(f, p);
 183     }
 184 
 185     /**
 186      * {@inheritDoc} This implementation calls {@code defaultAction}.
 187      *
 188      * @param i {@inheritDoc}
 189      * @param p {@inheritDoc}
 190      * @return  the result of {@code defaultAction}
 191      */
 192     public R visitInt(int i, P p) {
 193         return defaultAction(i, p);
 194     }
 195 
 196     /**
 197      * {@inheritDoc} This implementation calls {@code defaultAction}.
 198      *
 199      * @param i {@inheritDoc}
 200      * @param p {@inheritDoc}
 201      * @return  the result of {@code defaultAction}
 202      */
 203     public R visitLong(long i, P p) {
 204         return defaultAction(i, p);
 205     }
 206 
 207     /**
 208      * {@inheritDoc} This implementation calls {@code defaultAction}.
 209      *
 210      * @param s {@inheritDoc}
 211      * @param p {@inheritDoc}
 212      * @return  the result of {@code defaultAction}
 213      */
 214     public R visitShort(short s, P p) {
 215         return defaultAction(s, p);
 216     }
 217 
 218     /**
 219      * {@inheritDoc} This implementation calls {@code defaultAction}.
 220      *
 221      * @param s {@inheritDoc}
 222      * @param p {@inheritDoc}
 223      * @return  the result of {@code defaultAction}
 224      */
 225     public R visitString(String s, P p) {
 226         return defaultAction(s, p);
 227     }
 228 
 229     /**
 230      * {@inheritDoc} This implementation calls {@code defaultAction}.
 231      *
 232      * @param t {@inheritDoc}
 233      * @param p {@inheritDoc}
 234      * @return  the result of {@code defaultAction}
 235      */
 236     public R visitType(TypeMirror t, P p) {
 237         return defaultAction(t, p);
 238     }
 239 
 240     /**
 241      * {@inheritDoc} This implementation calls {@code defaultAction}.
 242      *
 243      * @param c {@inheritDoc}
 244      * @param p {@inheritDoc}
 245      * @return  the result of {@code defaultAction}
 246      */
 247     public R visitEnumConstant(VariableElement c, P p) {
 248         return defaultAction(c, p);
 249     }
 250 
 251     /**
 252      * {@inheritDoc} This implementation calls {@code defaultAction}.
 253      *
 254      * @param a {@inheritDoc}
 255      * @param p {@inheritDoc}
 256      * @return  the result of {@code defaultAction}
 257      */
 258     public R visitAnnotation(AnnotationMirror a, P p) {
 259         return defaultAction(a, p);
 260     }
 261 
 262     /**
 263      * {@inheritDoc} This implementation calls {@code defaultAction}.
 264      *
 265      * @param vals {@inheritDoc}
 266      * @param p {@inheritDoc}
 267      * @return  the result of {@code defaultAction}
 268      */
 269     public R visitArray(List<? extends AnnotationValue> vals, P p) {
 270         return defaultAction(vals, p);
 271     }
 272 }