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comparison: src/share/classes/com/sun/source/util/TreeScanner.java

src/share/classes/com/sun/source/util/TreeScanner.java

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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 com.sun.source.util;
27
28 import com.sun.source.tree.*;
29
30 /**
31 * A TreeVisitor that visits all the child tree nodes.
32 * To visit nodes of a particular type, just override the
33 * corresponding visitXYZ method.
34 * Inside your method, call super.visitXYZ to visit descendant
35 * nodes.
36 *
37 * <p>The default implementation of the visitXYZ methods will determine
38 * a result as follows:
39 * <ul>
40 * <li>If the node being visited has no children, the result will be null.
41 * <li>If the node being visited has one child, the result will be the
42 * result of calling {@code scan} on that child. The child may be a simple node
43 * or itself a list of nodes.
44 * <li> If the node being visited has more than one child, the result will
45 * be determined by calling {@code scan} each child in turn, and then combining the
46 * result of each scan after the first with the cumulative result
47 * so far, as determined by the {@link #reduce} method. Each child may be either
48 * a simple node of a list of nodes. The default behavior of the {@code reduce}
49 * method is such that the result of the visitXYZ method will be the result of
50 * the last child scanned.
51 * </ul>
52 *
53 * <p>Here is an example to count the number of identifier nodes in a tree:
54 * <pre>
55 * class CountIdentifiers extends TreeScanner&lt;Integer,Void&gt; {
56 * {@literal @}Override
57 * public Integer visitIdentifier(IdentifierTree node, Void p) {
58 * return 1;
59 * }
60 * {@literal @}Override
61 * public Integer reduce(Integer r1, Integer r2) {
62 * return (r1 == null ? 0 : r1) + (r2 == null ? 0 : r2);
63 * }
64 * }
65 * </pre>
66 *
67 * @author Peter von der Ah&eacute;
68 * @author Jonathan Gibbons
69 * @since 1.6
70 */
71 @jdk.Exported
72 public class TreeScanner<R,P> implements TreeVisitor<R,P> {
73
74 /** Scan a single node.
75 */
76 public R scan(Tree node, P p) {
77 return (node == null) ? null : node.accept(this, p);
78 }
79
80 private R scanAndReduce(Tree node, P p, R r) {
81 return reduce(scan(node, p), r);
82 }
83
84 /** Scan a list of nodes.
85 */
86 public R scan(Iterable<? extends Tree> nodes, P p) {
87 R r = null;
88 if (nodes != null) {
89 boolean first = true;
90 for (Tree node : nodes) {
91 r = (first ? scan(node, p) : scanAndReduce(node, p, r));
92 first = false;
93 }
94 }
95 return r;
96 }
97
98 private R scanAndReduce(Iterable<? extends Tree> nodes, P p, R r) {
99 return reduce(scan(nodes, p), r);
100 }
101
102 /**
103 * Reduces two results into a combined result.
104 * The default implementation is to return the first parameter.
105 * The general contract of the method is that it may take any action whatsoever.
106 */
107 public R reduce(R r1, R r2) {
108 return r1;
109 }
110
111
112 /* ***************************************************************************
113 * Visitor methods
114 ****************************************************************************/
115
116 public R visitCompilationUnit(CompilationUnitTree node, P p) {
117 R r = scan(node.getPackageAnnotations(), p);
118 r = scanAndReduce(node.getPackageName(), p, r);
119 r = scanAndReduce(node.getImports(), p, r);
120 r = scanAndReduce(node.getTypeDecls(), p, r);
121 return r;
122 }
123
124 public R visitImport(ImportTree node, P p) {
125 return scan(node.getQualifiedIdentifier(), p);
126 }
127
128 public R visitClass(ClassTree node, P p) {
129 R r = scan(node.getModifiers(), p);
130 r = scanAndReduce(node.getTypeParameters(), p, r);
131 r = scanAndReduce(node.getExtendsClause(), p, r);
132 r = scanAndReduce(node.getImplementsClause(), p, r);
133 r = scanAndReduce(node.getMembers(), p, r);
134 return r;
135 }
136
137 public R visitMethod(MethodTree node, P p) {
138 R r = scan(node.getModifiers(), p);
139 r = scanAndReduce(node.getReturnType(), p, r);
140 r = scanAndReduce(node.getTypeParameters(), p, r);
141 r = scanAndReduce(node.getParameters(), p, r);
142 r = scanAndReduce(node.getReceiverParameter(), p, r);
143 r = scanAndReduce(node.getThrows(), p, r);
144 r = scanAndReduce(node.getBody(), p, r);
145 r = scanAndReduce(node.getDefaultValue(), p, r);
146 return r;
147 }
148
149 public R visitVariable(VariableTree node, P p) {
150 R r = scan(node.getModifiers(), p);
151 r = scanAndReduce(node.getType(), p, r);
152 r = scanAndReduce(node.getNameExpression(), p, r);
153 r = scanAndReduce(node.getInitializer(), p, r);
154 return r;
155 }
156
157 public R visitEmptyStatement(EmptyStatementTree node, P p) {
158 return null;
159 }
160
161 public R visitBlock(BlockTree node, P p) {
162 return scan(node.getStatements(), p);
163 }
164
165 public R visitDoWhileLoop(DoWhileLoopTree node, P p) {
166 R r = scan(node.getStatement(), p);
167 r = scanAndReduce(node.getCondition(), p, r);
168 return r;
169 }
170
171 public R visitWhileLoop(WhileLoopTree node, P p) {
172 R r = scan(node.getCondition(), p);
173 r = scanAndReduce(node.getStatement(), p, r);
174 return r;
175 }
176
177 public R visitForLoop(ForLoopTree node, P p) {
178 R r = scan(node.getInitializer(), p);
179 r = scanAndReduce(node.getCondition(), p, r);
180 r = scanAndReduce(node.getUpdate(), p, r);
181 r = scanAndReduce(node.getStatement(), p, r);
182 return r;
183 }
184
185 public R visitEnhancedForLoop(EnhancedForLoopTree node, P p) {
186 R r = scan(node.getVariable(), p);
187 r = scanAndReduce(node.getExpression(), p, r);
188 r = scanAndReduce(node.getStatement(), p, r);
189 return r;
190 }
191
192 public R visitLabeledStatement(LabeledStatementTree node, P p) {
193 return scan(node.getStatement(), p);
194 }
195
196 public R visitSwitch(SwitchTree node, P p) {
197 R r = scan(node.getExpression(), p);
198 r = scanAndReduce(node.getCases(), p, r);
199 return r;
200 }
201
202 public R visitCase(CaseTree node, P p) {
203 R r = scan(node.getExpression(), p);
204 r = scanAndReduce(node.getStatements(), p, r);
205 return r;
206 }
207
208 public R visitSynchronized(SynchronizedTree node, P p) {
209 R r = scan(node.getExpression(), p);
210 r = scanAndReduce(node.getBlock(), p, r);
211 return r;
212 }
213
214 public R visitTry(TryTree node, P p) {
215 R r = scan(node.getResources(), p);
216 r = scanAndReduce(node.getBlock(), p, r);
217 r = scanAndReduce(node.getCatches(), p, r);
218 r = scanAndReduce(node.getFinallyBlock(), p, r);
219 return r;
220 }
221
222 public R visitCatch(CatchTree node, P p) {
223 R r = scan(node.getParameter(), p);
224 r = scanAndReduce(node.getBlock(), p, r);
225 return r;
226 }
227
228 public R visitConditionalExpression(ConditionalExpressionTree node, P p) {
229 R r = scan(node.getCondition(), p);
230 r = scanAndReduce(node.getTrueExpression(), p, r);
231 r = scanAndReduce(node.getFalseExpression(), p, r);
232 return r;
233 }
234
235 public R visitIf(IfTree node, P p) {
236 R r = scan(node.getCondition(), p);
237 r = scanAndReduce(node.getThenStatement(), p, r);
238 r = scanAndReduce(node.getElseStatement(), p, r);
239 return r;
240 }
241
242 public R visitExpressionStatement(ExpressionStatementTree node, P p) {
243 return scan(node.getExpression(), p);
244 }
245
246 public R visitBreak(BreakTree node, P p) {
247 return null;
248 }
249
250 public R visitContinue(ContinueTree node, P p) {
251 return null;
252 }
253
254 public R visitReturn(ReturnTree node, P p) {
255 return scan(node.getExpression(), p);
256 }
257
258 public R visitThrow(ThrowTree node, P p) {
259 return scan(node.getExpression(), p);
260 }
261
262 public R visitAssert(AssertTree node, P p) {
263 R r = scan(node.getCondition(), p);
264 r = scanAndReduce(node.getDetail(), p, r);
265 return r;
266 }
267
268 public R visitMethodInvocation(MethodInvocationTree node, P p) {
269 R r = scan(node.getTypeArguments(), p);
270 r = scanAndReduce(node.getMethodSelect(), p, r);
271 r = scanAndReduce(node.getArguments(), p, r);
272 return r;
273 }
274
275 public R visitNewClass(NewClassTree node, P p) {
276 R r = scan(node.getEnclosingExpression(), p);
277 r = scanAndReduce(node.getIdentifier(), p, r);
278 r = scanAndReduce(node.getTypeArguments(), p, r);
279 r = scanAndReduce(node.getArguments(), p, r);
280 r = scanAndReduce(node.getClassBody(), p, r);
281 return r;
282 }
283
284 public R visitNewArray(NewArrayTree node, P p) {
285 R r = scan(node.getType(), p);
286 r = scanAndReduce(node.getDimensions(), p, r);
287 r = scanAndReduce(node.getInitializers(), p, r);
288 r = scanAndReduce(node.getAnnotations(), p, r);
289 for (Iterable< ? extends Tree> dimAnno : node.getDimAnnotations()) {
290 r = scanAndReduce(dimAnno, p, r);
291 }
292 return r;
293 }
294
295 public R visitLambdaExpression(LambdaExpressionTree node, P p) {
296 R r = scan(node.getParameters(), p);
297 r = scanAndReduce(node.getBody(), p, r);
298 return r;
299 }
300
301 public R visitParenthesized(ParenthesizedTree node, P p) {
302 return scan(node.getExpression(), p);
303 }
304
305 public R visitAssignment(AssignmentTree node, P p) {
306 R r = scan(node.getVariable(), p);
307 r = scanAndReduce(node.getExpression(), p, r);
308 return r;
309 }
310
311 public R visitCompoundAssignment(CompoundAssignmentTree node, P p) {
312 R r = scan(node.getVariable(), p);
313 r = scanAndReduce(node.getExpression(), p, r);
314 return r;
315 }
316
317 public R visitUnary(UnaryTree node, P p) {
318 return scan(node.getExpression(), p);
319 }
320
321 public R visitBinary(BinaryTree node, P p) {
322 R r = scan(node.getLeftOperand(), p);
323 r = scanAndReduce(node.getRightOperand(), p, r);
324 return r;
325 }
326
327 public R visitTypeCast(TypeCastTree node, P p) {
328 R r = scan(node.getType(), p);
329 r = scanAndReduce(node.getExpression(), p, r);
330 return r;
331 }
332
333 public R visitInstanceOf(InstanceOfTree node, P p) {
334 R r = scan(node.getExpression(), p);
335 r = scanAndReduce(node.getType(), p, r);
336 return r;
337 }
338
339 public R visitArrayAccess(ArrayAccessTree node, P p) {
340 R r = scan(node.getExpression(), p);
341 r = scanAndReduce(node.getIndex(), p, r);
342 return r;
343 }
344
345 public R visitMemberSelect(MemberSelectTree node, P p) {
346 return scan(node.getExpression(), p);
347 }
348
349 public R visitMemberReference(MemberReferenceTree node, P p) {
350 R r = scan(node.getQualifierExpression(), p);
351 r = scanAndReduce(node.getTypeArguments(), p, r);
352 return r;
353 }
354
355 public R visitIdentifier(IdentifierTree node, P p) {
356 return null;
357 }
358
359 public R visitLiteral(LiteralTree node, P p) {
360 return null;
361 }
362
363 public R visitPrimitiveType(PrimitiveTypeTree node, P p) {
364 return null;
365 }
366
367 public R visitArrayType(ArrayTypeTree node, P p) {
368 return scan(node.getType(), p);
369 }
370
371 public R visitParameterizedType(ParameterizedTypeTree node, P p) {
372 R r = scan(node.getType(), p);
373 r = scanAndReduce(node.getTypeArguments(), p, r);
374 return r;
375 }
376
377 public R visitUnionType(UnionTypeTree node, P p) {
378 return scan(node.getTypeAlternatives(), p);
379 }
380
381 public R visitIntersectionType(IntersectionTypeTree node, P p) {
382 return scan(node.getBounds(), p);
383 }
384
385 public R visitTypeParameter(TypeParameterTree node, P p) {
386 R r = scan(node.getAnnotations(), p);
387 r = scanAndReduce(node.getBounds(), p, r);
388 return r;
389 }
390
391 public R visitWildcard(WildcardTree node, P p) {
392 return scan(node.getBound(), p);
393 }
394
395 public R visitModifiers(ModifiersTree node, P p) {
396 return scan(node.getAnnotations(), p);
397 }
398
399 public R visitAnnotation(AnnotationTree node, P p) {
400 R r = scan(node.getAnnotationType(), p);
401 r = scanAndReduce(node.getArguments(), p, r);
402 return r;
403 }
404
405 public R visitAnnotatedType(AnnotatedTypeTree node, P p) {
406 R r = scan(node.getAnnotations(), p);
407 r = scanAndReduce(node.getUnderlyingType(), p, r);
408 return r;
409 }
410
411 public R visitOther(Tree node, P p) {
412 return null;
413 }
414
415 public R visitErroneous(ErroneousTree node, P p) {
416 return null;
417 }
418 }

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