1 /*
2 * Copyright (c) 2005, 2017, 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.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} <code><i>Xyz</i></code> that may have more than one
40 * kind, the <code>visit<i>Xyz</i></code> methods in this class delegate
41 * to the <code>visit<i>Xyz</i>As<i>Kind</i></code> method corresponding to the
42 * first argument's kind. The <code>visit<i>Xyz</i>As<i>Kind</i></code> 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 *
80 * @see ElementKindVisitor7
81 * @see ElementKindVisitor8
82 * @see ElementKindVisitor9
83 * @since 1.6
84 */
85 @SupportedSourceVersion(RELEASE_6)
86 public class ElementKindVisitor6<R, P>
87 extends SimpleElementVisitor6<R, P> {
88 /**
89 * Constructor for concrete subclasses; uses {@code null} for the
90 * default value.
91 * @deprecated Release 6 is obsolete; update to a visitor for a newer
92 * release level.
93 */
94 @Deprecated(since="9")
95 protected ElementKindVisitor6() {
96 super(null);
97 }
98
99 /**
100 * Constructor for concrete subclasses; uses the argument for the
101 * default value.
102 *
103 * @param defaultValue the value to assign to {@link #DEFAULT_VALUE}
104 * @deprecated Release 6 is obsolete; update to a visitor for a newer
105 * release level.
106 */
107 @Deprecated(since="9")
108 protected ElementKindVisitor6(R defaultValue) {
109 super(defaultValue);
110 }
111
112 /**
113 * {@inheritDoc}
114 *
115 * The element argument has kind {@code PACKAGE}.
116 *
117 * @param e {@inheritDoc}
118 * @param p {@inheritDoc}
119 * @return {@inheritDoc}
120 */
121 @Override
122 public R visitPackage(PackageElement e, P p) {
123 assert e.getKind() == PACKAGE: "Bad kind on PackageElement";
124 return defaultAction(e, p);
125 }
126
127 /**
128 * Visits a type element, dispatching to the visit method for the
129 * specific {@linkplain ElementKind kind} of type, {@code
130 * ANNOTATION_TYPE}, {@code CLASS}, {@code ENUM}, or {@code
131 * INTERFACE}.
132 *
133 * @param e {@inheritDoc}
134 * @param p {@inheritDoc}
135 * @return the result of the kind-specific visit method
136 */
137 @Override
138 public R visitType(TypeElement e, P p) {
139 ElementKind k = e.getKind();
140 switch(k) {
141 case ANNOTATION_TYPE:
142 return visitTypeAsAnnotationType(e, p);
143
144 case CLASS:
145 return visitTypeAsClass(e, p);
146
147 case ENUM:
148 return visitTypeAsEnum(e, p);
149
150 case INTERFACE:
151 return visitTypeAsInterface(e, p);
152
153 default:
154 throw new AssertionError("Bad kind " + k + " for TypeElement" + e);
155 }
156 }
157
158 /**
159 * Visits an {@code ANNOTATION_TYPE} type element by calling
160 * {@code defaultAction}.
161 *
162 * @param e the element to visit
163 * @param p a visitor-specified parameter
164 * @return the result of {@code defaultAction}
165 */
166 public R visitTypeAsAnnotationType(TypeElement e, P p) {
167 return defaultAction(e, p);
168 }
169
170 /**
171 * Visits a {@code CLASS} type element by calling {@code
172 * defaultAction}.
173 *
174 * @param e the element to visit
175 * @param p a visitor-specified parameter
176 * @return the result of {@code defaultAction}
177 */
178 public R visitTypeAsClass(TypeElement e, P p) {
179 return defaultAction(e, p);
180 }
181
182 /**
183 * Visits an {@code ENUM} type element by calling {@code
184 * defaultAction}.
185 *
186 * @param e the element to visit
187 * @param p a visitor-specified parameter
188 * @return the result of {@code defaultAction}
189 */
190 public R visitTypeAsEnum(TypeElement e, P p) {
191 return defaultAction(e, p);
192 }
193
194 /**
195 * Visits an {@code INTERFACE} type element by calling {@code
196 * defaultAction}.
197 *.
198 * @param e the element to visit
199 * @param p a visitor-specified parameter
200 * @return the result of {@code defaultAction}
201 */
202 public R visitTypeAsInterface(TypeElement e, P p) {
203 return defaultAction(e, p);
204 }
205
206 /**
207 * Visits a variable element, dispatching to the visit method for
208 * the specific {@linkplain ElementKind kind} of variable, {@code
209 * ENUM_CONSTANT}, {@code EXCEPTION_PARAMETER}, {@code FIELD},
210 * {@code LOCAL_VARIABLE}, {@code PARAMETER}, or {@code RESOURCE_VARIABLE}.
211 *
212 * @param e {@inheritDoc}
213 * @param p {@inheritDoc}
214 * @return the result of the kind-specific visit method
215 */
216 @Override
217 public R visitVariable(VariableElement e, P p) {
218 ElementKind k = e.getKind();
219 switch(k) {
220 case ENUM_CONSTANT:
221 return visitVariableAsEnumConstant(e, p);
222
223 case EXCEPTION_PARAMETER:
224 return visitVariableAsExceptionParameter(e, p);
225
226 case FIELD:
227 return visitVariableAsField(e, p);
228
229 case LOCAL_VARIABLE:
230 return visitVariableAsLocalVariable(e, p);
231
232 case PARAMETER:
233 return visitVariableAsParameter(e, p);
234
235 case RESOURCE_VARIABLE:
236 return visitVariableAsResourceVariable(e, p);
237
238 default:
239 throw new AssertionError("Bad kind " + k + " for VariableElement" + e);
240 }
241 }
242
243 /**
244 * Visits an {@code ENUM_CONSTANT} variable element by calling
245 * {@code defaultAction}.
246 *
247 * @param e the element to visit
248 * @param p a visitor-specified parameter
249 * @return the result of {@code defaultAction}
250 */
251 public R visitVariableAsEnumConstant(VariableElement e, P p) {
252 return defaultAction(e, p);
253 }
254
255 /**
256 * Visits an {@code EXCEPTION_PARAMETER} variable element by calling
257 * {@code defaultAction}.
258 *
259 * @param e the element to visit
260 * @param p a visitor-specified parameter
261 * @return the result of {@code defaultAction}
262 */
263 public R visitVariableAsExceptionParameter(VariableElement e, P p) {
264 return defaultAction(e, p);
265 }
266
267 /**
268 * Visits a {@code FIELD} variable element by calling
269 * {@code defaultAction}.
270 *
271 * @param e the element to visit
272 * @param p a visitor-specified parameter
273 * @return the result of {@code defaultAction}
274 */
275 public R visitVariableAsField(VariableElement e, P p) {
276 return defaultAction(e, p);
277 }
278
279 /**
280 * Visits a {@code LOCAL_VARIABLE} variable element by calling
281 * {@code defaultAction}.
282 *
283 * @param e the element to visit
284 * @param p a visitor-specified parameter
285 * @return the result of {@code defaultAction}
286 */
287 public R visitVariableAsLocalVariable(VariableElement e, P p) {
288 return defaultAction(e, p);
289 }
290
291 /**
292 * Visits a {@code PARAMETER} variable element by calling
293 * {@code defaultAction}.
294 *
295 * @param e the element to visit
296 * @param p a visitor-specified parameter
297 * @return the result of {@code defaultAction}
298 */
299 public R visitVariableAsParameter(VariableElement e, P p) {
300 return defaultAction(e, p);
301 }
302
303 /**
304 * Visits a {@code RESOURCE_VARIABLE} variable element by calling
305 * {@code visitUnknown}.
306 *
307 * @param e the element to visit
308 * @param p a visitor-specified parameter
309 * @return the result of {@code visitUnknown}
310 *
311 * @since 1.7
312 */
313 public R visitVariableAsResourceVariable(VariableElement e, P p) {
314 return visitUnknown(e, p);
315 }
316
317 /**
318 * Visits an executable element, dispatching to the visit method
319 * for the specific {@linkplain ElementKind kind} of executable,
320 * {@code CONSTRUCTOR}, {@code INSTANCE_INIT}, {@code METHOD}, or
321 * {@code STATIC_INIT}.
322 *
323 * @param e {@inheritDoc}
324 * @param p {@inheritDoc}
325 * @return the result of the kind-specific visit method
326 */
327 @Override
328 public R visitExecutable(ExecutableElement e, P p) {
329 ElementKind k = e.getKind();
330 switch(k) {
331 case CONSTRUCTOR:
332 return visitExecutableAsConstructor(e, p);
333
334 case INSTANCE_INIT:
335 return visitExecutableAsInstanceInit(e, p);
336
337 case METHOD:
338 return visitExecutableAsMethod(e, p);
339
340 case STATIC_INIT:
341 return visitExecutableAsStaticInit(e, p);
342
343 default:
344 throw new AssertionError("Bad kind " + k + " for ExecutableElement" + e);
345 }
346 }
347
348 /**
349 * Visits a {@code CONSTRUCTOR} executable element by calling
350 * {@code defaultAction}.
351 *
352 * @param e the element to visit
353 * @param p a visitor-specified parameter
354 * @return the result of {@code defaultAction}
355 */
356 public R visitExecutableAsConstructor(ExecutableElement e, P p) {
357 return defaultAction(e, p);
358 }
359
360 /**
361 * Visits an {@code INSTANCE_INIT} executable element by calling
362 * {@code defaultAction}.
363 *
364 * @param e the element to visit
365 * @param p a visitor-specified parameter
366 * @return the result of {@code defaultAction}
367 */
368 public R visitExecutableAsInstanceInit(ExecutableElement e, P p) {
369 return defaultAction(e, p);
370 }
371
372 /**
373 * Visits a {@code METHOD} executable element by calling
374 * {@code defaultAction}.
375 *
376 * @param e the element to visit
377 * @param p a visitor-specified parameter
378 * @return the result of {@code defaultAction}
379 */
380 public R visitExecutableAsMethod(ExecutableElement e, P p) {
381 return defaultAction(e, p);
382 }
383
384 /**
385 * Visits a {@code STATIC_INIT} executable element by calling
386 * {@code defaultAction}.
387 *
388 * @param e the element to visit
389 * @param p a visitor-specified parameter
390 * @return the result of {@code defaultAction}
391 */
392 public R visitExecutableAsStaticInit(ExecutableElement e, P p) {
393 return defaultAction(e, p);
394 }
395
396
397 /**
398 * {@inheritDoc}
399 *
400 * The element argument has kind {@code TYPE_PARAMETER}.
401 *
402 * @param e {@inheritDoc}
403 * @param p {@inheritDoc}
404 * @return {@inheritDoc}
405 */
406 @Override
407 public R visitTypeParameter(TypeParameterElement e, P p) {
408 assert e.getKind() == TYPE_PARAMETER: "Bad kind on TypeParameterElement";
409 return defaultAction(e, p);
410 }
411 }