| 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.element.*; |
| 29 | import static javax.lang.model.element.ElementKind.*; |
| 30 | import javax.annotation.processing.SupportedSourceVersion; |
| 31 | import static javax.lang.model.SourceVersion.*; |
| 32 | import javax.lang.model.SourceVersion; |
| 33 | |
| 34 | |
| 35 | /** |
| 36 | * A visitor of program elements based on their {@linkplain |
| 37 | * ElementKind kind} with default behavior appropriate for the {@link |
| 38 | * SourceVersion#RELEASE_6 RELEASE_6} source version. For {@linkplain |
| 39 | * Element elements} <tt><i>XYZ</i></tt> that may have more than one |
| 40 | * kind, the <tt>visit<i>XYZ</i></tt> methods in this class delegate |
| 41 | * to the <tt>visit<i>XYZKind</i></tt> method corresponding to the |
| 42 | * first argument's kind. The <tt>visit<i>XYZKind</i></tt> methods |
| 43 | * call {@link #defaultAction defaultAction}, passing their arguments |
| 44 | * to {@code defaultAction}'s corresponding parameters. |
| 45 | * |
| 46 | * <p> Methods in this class may be overridden subject to their |
| 47 | * general contract. Note that annotating methods in concrete |
| 48 | * subclasses with {@link java.lang.Override @Override} will help |
| 49 | * ensure that methods are overridden as intended. |
| 50 | * |
| 51 | * <p> <b>WARNING:</b> The {@code ElementVisitor} interface |
| 52 | * implemented by this class may have methods added to it or the |
| 53 | * {@code ElementKind} {@code enum} used in this case may have |
| 54 | * constants added to it in the future to accommodate new, currently |
| 55 | * unknown, language structures added to future versions of the |
| 56 | * Java™ programming language. Therefore, methods whose names |
| 57 | * begin with {@code "visit"} may be added to this class in the |
| 58 | * future; to avoid incompatibilities, classes which extend this class |
| 59 | * should not declare any instance methods with names beginning with |
| 60 | * {@code "visit"}. |
| 61 | * |
| 62 | * <p>When such a new visit method is added, the default |
| 63 | * implementation in this class will be to call the {@link |
| 64 | * #visitUnknown visitUnknown} method. A new abstract element kind |
| 65 | * visitor class will also be introduced to correspond to the new |
| 66 | * language level; this visitor will have different default behavior |
| 67 | * for the visit method in question. When the new visitor is |
| 68 | * introduced, all or portions of this visitor may be deprecated. |
| 69 | * |
| 70 | * @param <R> the return type of this visitor's methods. Use {@link |
| 71 | * Void} for visitors that do not need to return results. |
| 72 | * @param <P> the type of the additional parameter to this visitor's |
| 73 | * methods. Use {@code Void} for visitors that do not need an |
| 74 | * additional parameter. |
| 75 | * |
| 76 | * @author Joseph D. Darcy |
| 77 | * @author Scott Seligman |
| 78 | * @author Peter von der Ahé |
| 79 | * @since 1.6 |
| 80 | */ |
| 81 | @SupportedSourceVersion(RELEASE_6) |
| 82 | public class ElementKindVisitor6<R, P> |
| 83 | extends SimpleElementVisitor6<R, P> { |
| 84 | /** |
| 85 | * Constructor for concrete subclasses; uses {@code null} for the |
| 86 | * default value. |
| 87 | */ |
| 88 | protected ElementKindVisitor6() { |
| 89 | super(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 ElementKindVisitor6(R defaultValue) { |
| 99 | super(defaultValue); |
| 100 | } |
| 101 | |
| 102 | /** |
| 103 | * {@inheritDoc} |
| 104 | * |
| 105 | * The element argument has kind {@code PACKAGE}. |
| 106 | * |
| 107 | * @param e {@inheritDoc} |
| 108 | * @param p {@inheritDoc} |
| 109 | * @return {@inheritDoc} |
| 110 | */ |
| 111 | @Override |
| 112 | public R visitPackage(PackageElement e, P p) { |
| 113 | assert e.getKind() == PACKAGE: "Bad kind on PackageElement"; |
| 114 | return defaultAction(e, p); |
| 115 | } |
| 116 | |
| 117 | /** |
| 118 | * Visits a type element, dispatching to the visit method for the |
| 119 | * specific {@linkplain ElementKind kind} of type, {@code |
| 120 | * ANNOTATION_TYPE}, {@code CLASS}, {@code ENUM}, or {@code |
| 121 | * INTERFACE}. |
| 122 | * |
| 123 | * @param e {@inheritDoc} |
| 124 | * @param p {@inheritDoc} |
| 125 | * @return the result of the kind-specific visit method |
| 126 | */ |
| 127 | @Override |
| 128 | public R visitType(TypeElement e, P p) { |
| 129 | ElementKind k = e.getKind(); |
| 130 | switch(k) { |
| 131 | case ANNOTATION_TYPE: |
| 132 | return visitTypeAsAnnotationType(e, p); |
| 133 | |
| 134 | case CLASS: |
| 135 | return visitTypeAsClass(e, p); |
| 136 | |
| 137 | case ENUM: |
| 138 | return visitTypeAsEnum(e, p); |
| 139 | |
| 140 | case INTERFACE: |
| 141 | return visitTypeAsInterface(e, p); |
| 142 | |
| 143 | default: |
| 144 | throw new AssertionError("Bad kind " + k + " for TypeElement" + e); |
| 145 | } |
| 146 | } |
| 147 | |
| 148 | /** |
| 149 | * Visits an {@code ANNOTATION_TYPE} type element by calling |
| 150 | * {@code defaultAction}. |
| 151 | * |
| 152 | * @param e the element to visit |
| 153 | * @param p a visitor-specified parameter |
| 154 | * @return the result of {@code defaultAction} |
| 155 | */ |
| 156 | public R visitTypeAsAnnotationType(TypeElement e, P p) { |
| 157 | return defaultAction(e, p); |
| 158 | } |
| 159 | |
| 160 | /** |
| 161 | * Visits a {@code CLASS} type element by calling {@code |
| 162 | * defaultAction}. |
| 163 | * |
| 164 | * @param e the element to visit |
| 165 | * @param p a visitor-specified parameter |
| 166 | * @return the result of {@code defaultAction} |
| 167 | */ |
| 168 | public R visitTypeAsClass(TypeElement e, P p) { |
| 169 | return defaultAction(e, p); |
| 170 | } |
| 171 | |
| 172 | /** |
| 173 | * Visits an {@code ENUM} type element by calling {@code |
| 174 | * defaultAction}. |
| 175 | * |
| 176 | * @param e the element to visit |
| 177 | * @param p a visitor-specified parameter |
| 178 | * @return the result of {@code defaultAction} |
| 179 | */ |
| 180 | public R visitTypeAsEnum(TypeElement e, P p) { |
| 181 | return defaultAction(e, p); |
| 182 | } |
| 183 | |
| 184 | /** |
| 185 | * Visits an {@code INTERFACE} type element by calling {@code |
| 186 | * defaultAction}. |
| 187 | *. |
| 188 | * @param e the element to visit |
| 189 | * @param p a visitor-specified parameter |
| 190 | * @return the result of {@code defaultAction} |
| 191 | */ |
| 192 | public R visitTypeAsInterface(TypeElement e, P p) { |
| 193 | return defaultAction(e, p); |
| 194 | } |
| 195 | |
| 196 | /** |
| 197 | * Visits a variable element, dispatching to the visit method for |
| 198 | * the specific {@linkplain ElementKind kind} of variable, {@code |
| 199 | * ENUM_CONSTANT}, {@code EXCEPTION_PARAMETER}, {@code FIELD}, |
| 200 | * {@code LOCAL_VARIABLE}, or {@code PARAMETER}. |
| 201 | * @param e {@inheritDoc} |
| 202 | * @param p {@inheritDoc} |
| 203 | * @return the result of the kind-specific visit method |
| 204 | */ |
| 205 | @Override |
| 206 | public R visitVariable(VariableElement e, P p) { |
| 207 | ElementKind k = e.getKind(); |
| 208 | switch(k) { |
| 209 | case ENUM_CONSTANT: |
| 210 | return visitVariableAsEnumConstant(e, p); |
| 211 | |
| 212 | case EXCEPTION_PARAMETER: |
| 213 | return visitVariableAsExceptionParameter(e, p); |
| 214 | |
| 215 | case FIELD: |
| 216 | return visitVariableAsField(e, p); |
| 217 | |
| 218 | case LOCAL_VARIABLE: |
| 219 | return visitVariableAsLocalVariable(e, p); |
| 220 | |
| 221 | case PARAMETER: |
| 222 | return visitVariableAsParameter(e, p); |
| 223 | |
| 224 | default: |
| 225 | throw new AssertionError("Bad kind " + k + " for VariableElement" + e); |
| 226 | } |
| 227 | |
| 228 | } |
| 229 | |
| 230 | /** |
| 231 | * Visits an {@code ENUM_CONSTANT} variable element by calling |
| 232 | * {@code defaultAction}. |
| 233 | * |
| 234 | * @param e the element to visit |
| 235 | * @param p a visitor-specified parameter |
| 236 | * @return the result of {@code defaultAction} |
| 237 | */ |
| 238 | public R visitVariableAsEnumConstant(VariableElement e, P p) { |
| 239 | return defaultAction(e, p); |
| 240 | } |
| 241 | |
| 242 | /** |
| 243 | * Visits an {@code EXCEPTION_PARAMETER} variable element by calling |
| 244 | * {@code defaultAction}. |
| 245 | * |
| 246 | * @param e the element to visit |
| 247 | * @param p a visitor-specified parameter |
| 248 | * @return the result of {@code defaultAction} |
| 249 | */ |
| 250 | public R visitVariableAsExceptionParameter(VariableElement e, P p) { |
| 251 | return defaultAction(e, p); |
| 252 | } |
| 253 | |
| 254 | /** |
| 255 | * Visits a {@code FIELD} variable element by calling |
| 256 | * {@code defaultAction}. |
| 257 | * |
| 258 | * @param e the element to visit |
| 259 | * @param p a visitor-specified parameter |
| 260 | * @return the result of {@code defaultAction} |
| 261 | */ |
| 262 | public R visitVariableAsField(VariableElement e, P p) { |
| 263 | return defaultAction(e, p); |
| 264 | } |
| 265 | |
| 266 | /** |
| 267 | * Visits a {@code LOCAL_VARIABLE} variable element by calling |
| 268 | * {@code defaultAction}. |
| 269 | * |
| 270 | * @param e the element to visit |
| 271 | * @param p a visitor-specified parameter |
| 272 | * @return the result of {@code defaultAction} |
| 273 | */ |
| 274 | public R visitVariableAsLocalVariable(VariableElement e, P p) { |
| 275 | return defaultAction(e, p); |
| 276 | } |
| 277 | |
| 278 | /** |
| 279 | * Visits a {@code PARAMETER} variable element by calling |
| 280 | * {@code defaultAction}. |
| 281 | * |
| 282 | * @param e the element to visit |
| 283 | * @param p a visitor-specified parameter |
| 284 | * @return the result of {@code defaultAction} |
| 285 | */ |
| 286 | public R visitVariableAsParameter(VariableElement e, P p) { |
| 287 | return defaultAction(e, p); |
| 288 | } |
| 289 | |
| 290 | /** |
| 291 | * Visits an executable element, dispatching to the visit method |
| 292 | * for the specific {@linkplain ElementKind kind} of executable, |
| 293 | * {@code CONSTRUCTOR}, {@code INSTANCE_INIT}, {@code METHOD}, or |
| 294 | * {@code STATIC_INIT}. |
| 295 | * |
| 296 | * @param e {@inheritDoc} |
| 297 | * @param p {@inheritDoc} |
| 298 | * @return the result of the kind-specific visit method |
| 299 | */ |
| 300 | @Override |
| 301 | public R visitExecutable(ExecutableElement e, P p) { |
| 302 | ElementKind k = e.getKind(); |
| 303 | switch(k) { |
| 304 | case CONSTRUCTOR: |
| 305 | return visitExecutableAsConstructor(e, p); |
| 306 | |
| 307 | case INSTANCE_INIT: |
| 308 | return visitExecutableAsInstanceInit(e, p); |
| 309 | |
| 310 | case METHOD: |
| 311 | return visitExecutableAsMethod(e, p); |
| 312 | |
| 313 | case STATIC_INIT: |
| 314 | return visitExecutableAsStaticInit(e, p); |
| 315 | |
| 316 | default: |
| 317 | throw new AssertionError("Bad kind " + k + " for ExecutableElement" + e); |
| 318 | } |
| 319 | } |
| 320 | |
| 321 | /** |
| 322 | * Visits a {@code CONSTRUCTOR} executable element by calling |
| 323 | * {@code defaultAction}. |
| 324 | * |
| 325 | * @param e the element to visit |
| 326 | * @param p a visitor-specified parameter |
| 327 | * @return the result of {@code defaultAction} |
| 328 | */ |
| 329 | public R visitExecutableAsConstructor(ExecutableElement e, P p) { |
| 330 | return defaultAction(e, p); |
| 331 | } |
| 332 | |
| 333 | /** |
| 334 | * Visits an {@code INSTANCE_INIT} executable element by calling |
| 335 | * {@code defaultAction}. |
| 336 | * |
| 337 | * @param e the element to visit |
| 338 | * @param p a visitor-specified parameter |
| 339 | * @return the result of {@code defaultAction} |
| 340 | */ |
| 341 | public R visitExecutableAsInstanceInit(ExecutableElement e, P p) { |
| 342 | return defaultAction(e, p); |
| 343 | } |
| 344 | |
| 345 | /** |
| 346 | * Visits a {@code METHOD} executable element by calling |
| 347 | * {@code defaultAction}. |
| 348 | * |
| 349 | * @param e the element to visit |
| 350 | * @param p a visitor-specified parameter |
| 351 | * @return the result of {@code defaultAction} |
| 352 | */ |
| 353 | public R visitExecutableAsMethod(ExecutableElement e, P p) { |
| 354 | return defaultAction(e, p); |
| 355 | } |
| 356 | |
| 357 | /** |
| 358 | * Visits a {@code STATIC_INIT} executable element by calling |
| 359 | * {@code defaultAction}. |
| 360 | * |
| 361 | * @param e the element to visit |
| 362 | * @param p a visitor-specified parameter |
| 363 | * @return the result of {@code defaultAction} |
| 364 | */ |
| 365 | public R visitExecutableAsStaticInit(ExecutableElement e, P p) { |
| 366 | return defaultAction(e, p); |
| 367 | } |
| 368 | |
| 369 | |
| 370 | /** |
| 371 | * {@inheritDoc} |
| 372 | * |
| 373 | * The element argument has kind {@code TYPE_PARAMETER}. |
| 374 | * |
| 375 | * @param e {@inheritDoc} |
| 376 | * @param p {@inheritDoc} |
| 377 | * @return {@inheritDoc} |
| 378 | */ |
| 379 | @Override |
| 380 | public R visitTypeParameter(TypeParameterElement e, P p) { |
| 381 | assert e.getKind() == TYPE_PARAMETER: "Bad kind on TypeParameterElement"; |
| 382 | return defaultAction(e, p); |
| 383 | } |
| 384 | } |