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src/share/classes/com/sun/source/util/TreeScanner.java@664edca41e34
src/share/classes/com/sun/source/util/TreeScanner.java
Fri, 26 Jun 2009 19:12:41 -0700
- author
- jjg
- date
- Fri, 26 Jun 2009 19:12:41 -0700
- changeset 309
- 664edca41e34
- parent 308
- 03944ee4fac4
- child 550
- a6f2911a7c55
- permissions
- -rw-r--r--
6855544: add missing files
Reviewed-by: jjg, mcimadamore, darcy
Contributed-by: mernst@cs.washington.edu, mali@csail.mit.edu, mpapi@csail.mit.edu
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 */
26 package com.sun.source.util;
28 import com.sun.source.tree.*;
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<Integer,Void> {
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 Ahé
68 * @author Jonathan Gibbons
69 * @since 1.6
70 */
71 public class TreeScanner<R,P> implements TreeVisitor<R,P> {
73 /** Scan a single node.
74 */
75 public R scan(Tree node, P p) {
76 return (node == null) ? null : node.accept(this, p);
77 }
79 private R scanAndReduce(Tree node, P p, R r) {
80 return reduce(scan(node, p), r);
81 }
83 /** Scan a list of nodes.
84 */
85 public R scan(Iterable<? extends Tree> nodes, P p) {
86 R r = null;
87 if (nodes != null) {
88 boolean first = true;
89 for (Tree node : nodes) {
90 r = (first ? scan(node, p) : scanAndReduce(node, p, r));
91 first = false;
92 }
93 }
94 return r;
95 }
97 private R scanAndReduce(Iterable<? extends Tree> nodes, P p, R r) {
98 return reduce(scan(nodes, p), r);
99 }
101 /**
102 * Reduces two results into a combined result.
103 * The default implementation is to return the first parameter.
104 * The general contract of the method is that it may take any action whatsoever.
105 */
106 public R reduce(R r1, R r2) {
107 return r1;
108 }
111 /* ***************************************************************************
112 * Visitor methods
113 ****************************************************************************/
115 public R visitCompilationUnit(CompilationUnitTree node, P p) {
116 R r = scan(node.getPackageAnnotations(), p);
117 r = scanAndReduce(node.getPackageName(), p, r);
118 r = scanAndReduce(node.getImports(), p, r);
119 r = scanAndReduce(node.getTypeDecls(), p, r);
120 return r;
121 }
123 public R visitImport(ImportTree node, P p) {
124 return scan(node.getQualifiedIdentifier(), p);
125 }
127 public R visitClass(ClassTree node, P p) {
128 R r = scan(node.getModifiers(), p);
129 r = scanAndReduce(node.getTypeParameters(), p, r);
130 r = scanAndReduce(node.getExtendsClause(), p, r);
131 r = scanAndReduce(node.getImplementsClause(), p, r);
132 r = scanAndReduce(node.getMembers(), p, r);
133 return r;
134 }
136 public R visitMethod(MethodTree node, P p) {
137 R r = scan(node.getModifiers(), p);
138 r = scanAndReduce(node.getReturnType(), p, r);
139 r = scanAndReduce(node.getTypeParameters(), p, r);
140 r = scanAndReduce(node.getParameters(), p, r);
141 r = scanAndReduce(node.getReceiverAnnotations(), p, r);
142 r = scanAndReduce(node.getThrows(), p, r);
143 r = scanAndReduce(node.getBody(), p, r);
144 return r;
145 }
147 public R visitVariable(VariableTree node, P p) {
148 R r = scan(node.getModifiers(), p);
149 r = scanAndReduce(node.getType(), p, r);
150 r = scanAndReduce(node.getInitializer(), p, r);
151 return r;
152 }
154 public R visitEmptyStatement(EmptyStatementTree node, P p) {
155 return null;
156 }
158 public R visitBlock(BlockTree node, P p) {
159 return scan(node.getStatements(), p);
160 }
162 public R visitDoWhileLoop(DoWhileLoopTree node, P p) {
163 R r = scan(node.getStatement(), p);
164 r = scanAndReduce(node.getCondition(), p, r);
165 return r;
166 }
168 public R visitWhileLoop(WhileLoopTree node, P p) {
169 R r = scan(node.getCondition(), p);
170 r = scanAndReduce(node.getStatement(), p, r);
171 return r;
172 }
174 public R visitForLoop(ForLoopTree node, P p) {
175 R r = scan(node.getInitializer(), p);
176 r = scanAndReduce(node.getCondition(), p, r);
177 r = scanAndReduce(node.getUpdate(), p, r);
178 r = scanAndReduce(node.getStatement(), p, r);
179 return r;
180 }
182 public R visitEnhancedForLoop(EnhancedForLoopTree node, P p) {
183 R r = scan(node.getVariable(), p);
184 r = scanAndReduce(node.getExpression(), p, r);
185 r = scanAndReduce(node.getStatement(), p, r);
186 return r;
187 }
189 public R visitLabeledStatement(LabeledStatementTree node, P p) {
190 return scan(node.getStatement(), p);
191 }
193 public R visitSwitch(SwitchTree node, P p) {
194 R r = scan(node.getExpression(), p);
195 r = scanAndReduce(node.getCases(), p, r);
196 return r;
197 }
199 public R visitCase(CaseTree node, P p) {
200 R r = scan(node.getExpression(), p);
201 r = scanAndReduce(node.getStatements(), p, r);
202 return r;
203 }
205 public R visitSynchronized(SynchronizedTree node, P p) {
206 R r = scan(node.getExpression(), p);
207 r = scanAndReduce(node.getBlock(), p, r);
208 return r;
209 }
211 public R visitTry(TryTree node, P p) {
212 R r = scan(node.getBlock(), p);
213 r = scanAndReduce(node.getCatches(), p, r);
214 r = scanAndReduce(node.getFinallyBlock(), p, r);
215 return r;
216 }
218 public R visitCatch(CatchTree node, P p) {
219 R r = scan(node.getParameter(), p);
220 r = scanAndReduce(node.getBlock(), p, r);
221 return r;
222 }
224 public R visitConditionalExpression(ConditionalExpressionTree node, P p) {
225 R r = scan(node.getCondition(), p);
226 r = scanAndReduce(node.getTrueExpression(), p, r);
227 r = scanAndReduce(node.getFalseExpression(), p, r);
228 return r;
229 }
231 public R visitIf(IfTree node, P p) {
232 R r = scan(node.getCondition(), p);
233 r = scanAndReduce(node.getThenStatement(), p, r);
234 r = scanAndReduce(node.getElseStatement(), p, r);
235 return r;
236 }
238 public R visitExpressionStatement(ExpressionStatementTree node, P p) {
239 return scan(node.getExpression(), p);
240 }
242 public R visitBreak(BreakTree node, P p) {
243 return null;
244 }
246 public R visitContinue(ContinueTree node, P p) {
247 return null;
248 }
250 public R visitReturn(ReturnTree node, P p) {
251 return scan(node.getExpression(), p);
252 }
254 public R visitThrow(ThrowTree node, P p) {
255 return scan(node.getExpression(), p);
256 }
258 public R visitAssert(AssertTree node, P p) {
259 R r = scan(node.getCondition(), p);
260 r = scanAndReduce(node.getDetail(), p, r);
261 return r;
262 }
264 public R visitMethodInvocation(MethodInvocationTree node, P p) {
265 R r = scan(node.getTypeArguments(), p);
266 r = scanAndReduce(node.getMethodSelect(), p, r);
267 r = scanAndReduce(node.getArguments(), p, r);
268 return r;
269 }
271 public R visitNewClass(NewClassTree node, P p) {
272 R r = scan(node.getEnclosingExpression(), p);
273 r = scanAndReduce(node.getIdentifier(), p, r);
274 r = scanAndReduce(node.getTypeArguments(), p, r);
275 r = scanAndReduce(node.getArguments(), p, r);
276 r = scanAndReduce(node.getClassBody(), p, r);
277 return r;
278 }
280 public R visitNewArray(NewArrayTree node, P p) {
281 R r = scan(node.getType(), p);
282 r = scanAndReduce(node.getDimensions(), p, r);
283 r = scanAndReduce(node.getInitializers(), p, r);
284 return r;
285 }
287 public R visitParenthesized(ParenthesizedTree node, P p) {
288 return scan(node.getExpression(), p);
289 }
291 public R visitAssignment(AssignmentTree node, P p) {
292 R r = scan(node.getVariable(), p);
293 r = scanAndReduce(node.getExpression(), p, r);
294 return r;
295 }
297 public R visitCompoundAssignment(CompoundAssignmentTree node, P p) {
298 R r = scan(node.getVariable(), p);
299 r = scanAndReduce(node.getExpression(), p, r);
300 return r;
301 }
303 public R visitUnary(UnaryTree node, P p) {
304 return scan(node.getExpression(), p);
305 }
307 public R visitBinary(BinaryTree node, P p) {
308 R r = scan(node.getLeftOperand(), p);
309 r = scanAndReduce(node.getRightOperand(), p, r);
310 return r;
311 }
313 public R visitTypeCast(TypeCastTree node, P p) {
314 R r = scan(node.getType(), p);
315 r = scanAndReduce(node.getExpression(), p, r);
316 return r;
317 }
319 public R visitInstanceOf(InstanceOfTree node, P p) {
320 R r = scan(node.getExpression(), p);
321 r = scanAndReduce(node.getType(), p, r);
322 return r;
323 }
325 public R visitArrayAccess(ArrayAccessTree node, P p) {
326 R r = scan(node.getExpression(), p);
327 r = scanAndReduce(node.getIndex(), p, r);
328 return r;
329 }
331 public R visitMemberSelect(MemberSelectTree node, P p) {
332 return scan(node.getExpression(), p);
333 }
335 public R visitIdentifier(IdentifierTree node, P p) {
336 return null;
337 }
339 public R visitLiteral(LiteralTree node, P p) {
340 return null;
341 }
343 public R visitPrimitiveType(PrimitiveTypeTree node, P p) {
344 return null;
345 }
347 public R visitArrayType(ArrayTypeTree node, P p) {
348 return scan(node.getType(), p);
349 }
351 public R visitParameterizedType(ParameterizedTypeTree node, P p) {
352 R r = scan(node.getType(), p);
353 r = scanAndReduce(node.getTypeArguments(), p, r);
354 return r;
355 }
357 public R visitTypeParameter(TypeParameterTree node, P p) {
358 R r = scan(node.getAnnotations(), p);
359 r = scanAndReduce(node.getBounds(), p, r);
360 return r;
361 }
363 public R visitWildcard(WildcardTree node, P p) {
364 return scan(node.getBound(), p);
365 }
367 public R visitModifiers(ModifiersTree node, P p) {
368 return scan(node.getAnnotations(), p);
369 }
371 public R visitAnnotation(AnnotationTree node, P p) {
372 R r = scan(node.getAnnotationType(), p);
373 r = scanAndReduce(node.getArguments(), p, r);
374 return r;
375 }
377 public R visitAnnotatedType(AnnotatedTypeTree node, P p) {
378 R r = scan(node.getAnnotations(), p);
379 r = scanAndReduce(node.getUnderlyingType(), p, r);
380 return r;
381 }
383 public R visitOther(Tree node, P p) {
384 return null;
385 }
387 public R visitErroneous(ErroneousTree node, P p) {
388 return null;
389 }
390 }
