001 /*
002 * Copyright 2005-2006 Sun Microsystems, Inc. All Rights Reserved.
003 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
004 *
005 * This code is free software; you can redistribute it and/or modify it
006 * under the terms of the GNU General Public License version 2 only, as
007 * published by the Free Software Foundation. Sun designates this
008 * particular file as subject to the "Classpath" exception as provided
009 * by Sun in the LICENSE file that accompanied this code.
010 *
011 * This code is distributed in the hope that it will be useful, but WITHOUT
012 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
013 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
014 * version 2 for more details (a copy is included in the LICENSE file that
015 * accompanied this code).
016 *
017 * You should have received a copy of the GNU General Public License version
018 * 2 along with this work; if not, write to the Free Software Foundation,
019 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
020 *
021 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
022 * CA 95054 USA or visit www.sun.com if you need additional information or
023 * have any questions.
024 */
025
026 package javax.lang.model.util;
027
028 import javax.lang.model.element.*;
029 import static javax.lang.model.element.ElementKind.*;
030 import javax.annotation.processing.SupportedSourceVersion;
031 import static javax.lang.model.SourceVersion.*;
032 import javax.lang.model.SourceVersion;
033
034
035 /**
036 * A visitor of program elements based on their {@linkplain
037 * ElementKind kind} with default behavior appropriate for the {@link
038 * SourceVersion#RELEASE_6 RELEASE_6} source version. For {@linkplain
039 * Element elements} <tt><i>XYZ</i></tt> that may have more than one
040 * kind, the <tt>visit<i>XYZ</i></tt> methods in this class delegate
041 * to the <tt>visit<i>XYZKind</i></tt> method corresponding to the
042 * first argument's kind. The <tt>visit<i>XYZKind</i></tt> methods
043 * call {@link #defaultAction defaultAction}, passing their arguments
044 * to {@code defaultAction}'s corresponding parameters.
045 *
046 * <p> Methods in this class may be overridden subject to their
047 * general contract. Note that annotating methods in concrete
048 * subclasses with {@link java.lang.Override @Override} will help
049 * ensure that methods are overridden as intended.
050 *
051 * <p> <b>WARNING:</b> The {@code ElementVisitor} interface
052 * implemented by this class may have methods added to it or the
053 * {@code ElementKind} {@code enum} used in this case may have
054 * constants added to it in the future to accommodate new, currently
055 * unknown, language structures added to future versions of the
056 * Java™ programming language. Therefore, methods whose names
057 * begin with {@code "visit"} may be added to this class in the
058 * future; to avoid incompatibilities, classes which extend this class
059 * should not declare any instance methods with names beginning with
060 * {@code "visit"}.
061 *
062 * <p>When such a new visit method is added, the default
063 * implementation in this class will be to call the {@link
064 * #visitUnknown visitUnknown} method. A new abstract element kind
065 * visitor class will also be introduced to correspond to the new
066 * language level; this visitor will have different default behavior
067 * for the visit method in question. When the new visitor is
068 * introduced, all or portions of this visitor may be deprecated.
069 *
070 * @param <R> the return type of this visitor's methods. Use {@link
071 * Void} for visitors that do not need to return results.
072 * @param <P> the type of the additional parameter to this visitor's
073 * methods. Use {@code Void} for visitors that do not need an
074 * additional parameter.
075 *
076 * @author Joseph D. Darcy
077 * @author Scott Seligman
078 * @author Peter von der Ahé
079 * @since 1.6
080 */
081 @SupportedSourceVersion(RELEASE_6)
082 public class ElementKindVisitor6<R, P>
083 extends SimpleElementVisitor6<R, P> {
084 /**
085 * Constructor for concrete subclasses; uses {@code null} for the
086 * default value.
087 */
088 protected ElementKindVisitor6() {
089 super(null);
090 }
091
092 /**
093 * Constructor for concrete subclasses; uses the argument for the
094 * default value.
095 *
096 * @param defaultValue the value to assign to {@link #DEFAULT_VALUE}
097 */
098 protected ElementKindVisitor6(R defaultValue) {
099 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 }