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

Wed, 27 Apr 2016 01:34:52 +0800

author
aoqi
date
Wed, 27 Apr 2016 01:34:52 +0800
changeset 0
959103a6100f
child 2525
2eb010b6cb22
permissions
-rw-r--r--

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http://hg.openjdk.java.net/jdk8u/jdk8u/langtools/
changeset: 2573:53ca196be1ae
tag: jdk8u25-b17

aoqi@0 1 /*
aoqi@0 2 * Copyright (c) 2005, 2013, Oracle and/or its affiliates. All rights reserved.
aoqi@0 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
aoqi@0 4 *
aoqi@0 5 * This code is free software; you can redistribute it and/or modify it
aoqi@0 6 * under the terms of the GNU General Public License version 2 only, as
aoqi@0 7 * published by the Free Software Foundation. Oracle designates this
aoqi@0 8 * particular file as subject to the "Classpath" exception as provided
aoqi@0 9 * by Oracle in the LICENSE file that accompanied this code.
aoqi@0 10 *
aoqi@0 11 * This code is distributed in the hope that it will be useful, but WITHOUT
aoqi@0 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
aoqi@0 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
aoqi@0 14 * version 2 for more details (a copy is included in the LICENSE file that
aoqi@0 15 * accompanied this code).
aoqi@0 16 *
aoqi@0 17 * You should have received a copy of the GNU General Public License version
aoqi@0 18 * 2 along with this work; if not, write to the Free Software Foundation,
aoqi@0 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
aoqi@0 20 *
aoqi@0 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
aoqi@0 22 * or visit www.oracle.com if you need additional information or have any
aoqi@0 23 * questions.
aoqi@0 24 */
aoqi@0 25
aoqi@0 26 package com.sun.source.util;
aoqi@0 27
aoqi@0 28 import com.sun.source.tree.*;
aoqi@0 29
aoqi@0 30 /**
aoqi@0 31 * A TreeVisitor that visits all the child tree nodes.
aoqi@0 32 * To visit nodes of a particular type, just override the
aoqi@0 33 * corresponding visitXYZ method.
aoqi@0 34 * Inside your method, call super.visitXYZ to visit descendant
aoqi@0 35 * nodes.
aoqi@0 36 *
aoqi@0 37 * <p>The default implementation of the visitXYZ methods will determine
aoqi@0 38 * a result as follows:
aoqi@0 39 * <ul>
aoqi@0 40 * <li>If the node being visited has no children, the result will be null.
aoqi@0 41 * <li>If the node being visited has one child, the result will be the
aoqi@0 42 * result of calling {@code scan} on that child. The child may be a simple node
aoqi@0 43 * or itself a list of nodes.
aoqi@0 44 * <li> If the node being visited has more than one child, the result will
aoqi@0 45 * be determined by calling {@code scan} each child in turn, and then combining the
aoqi@0 46 * result of each scan after the first with the cumulative result
aoqi@0 47 * so far, as determined by the {@link #reduce} method. Each child may be either
aoqi@0 48 * a simple node of a list of nodes. The default behavior of the {@code reduce}
aoqi@0 49 * method is such that the result of the visitXYZ method will be the result of
aoqi@0 50 * the last child scanned.
aoqi@0 51 * </ul>
aoqi@0 52 *
aoqi@0 53 * <p>Here is an example to count the number of identifier nodes in a tree:
aoqi@0 54 * <pre>
aoqi@0 55 * class CountIdentifiers extends TreeScanner&lt;Integer,Void&gt; {
aoqi@0 56 * {@literal @}Override
aoqi@0 57 * public Integer visitIdentifier(IdentifierTree node, Void p) {
aoqi@0 58 * return 1;
aoqi@0 59 * }
aoqi@0 60 * {@literal @}Override
aoqi@0 61 * public Integer reduce(Integer r1, Integer r2) {
aoqi@0 62 * return (r1 == null ? 0 : r1) + (r2 == null ? 0 : r2);
aoqi@0 63 * }
aoqi@0 64 * }
aoqi@0 65 * </pre>
aoqi@0 66 *
aoqi@0 67 * @author Peter von der Ah&eacute;
aoqi@0 68 * @author Jonathan Gibbons
aoqi@0 69 * @since 1.6
aoqi@0 70 */
aoqi@0 71 @jdk.Exported
aoqi@0 72 public class TreeScanner<R,P> implements TreeVisitor<R,P> {
aoqi@0 73
aoqi@0 74 /** Scan a single node.
aoqi@0 75 */
aoqi@0 76 public R scan(Tree node, P p) {
aoqi@0 77 return (node == null) ? null : node.accept(this, p);
aoqi@0 78 }
aoqi@0 79
aoqi@0 80 private R scanAndReduce(Tree node, P p, R r) {
aoqi@0 81 return reduce(scan(node, p), r);
aoqi@0 82 }
aoqi@0 83
aoqi@0 84 /** Scan a list of nodes.
aoqi@0 85 */
aoqi@0 86 public R scan(Iterable<? extends Tree> nodes, P p) {
aoqi@0 87 R r = null;
aoqi@0 88 if (nodes != null) {
aoqi@0 89 boolean first = true;
aoqi@0 90 for (Tree node : nodes) {
aoqi@0 91 r = (first ? scan(node, p) : scanAndReduce(node, p, r));
aoqi@0 92 first = false;
aoqi@0 93 }
aoqi@0 94 }
aoqi@0 95 return r;
aoqi@0 96 }
aoqi@0 97
aoqi@0 98 private R scanAndReduce(Iterable<? extends Tree> nodes, P p, R r) {
aoqi@0 99 return reduce(scan(nodes, p), r);
aoqi@0 100 }
aoqi@0 101
aoqi@0 102 /**
aoqi@0 103 * Reduces two results into a combined result.
aoqi@0 104 * The default implementation is to return the first parameter.
aoqi@0 105 * The general contract of the method is that it may take any action whatsoever.
aoqi@0 106 */
aoqi@0 107 public R reduce(R r1, R r2) {
aoqi@0 108 return r1;
aoqi@0 109 }
aoqi@0 110
aoqi@0 111
aoqi@0 112 /* ***************************************************************************
aoqi@0 113 * Visitor methods
aoqi@0 114 ****************************************************************************/
aoqi@0 115
aoqi@0 116 public R visitCompilationUnit(CompilationUnitTree node, P p) {
aoqi@0 117 R r = scan(node.getPackageAnnotations(), p);
aoqi@0 118 r = scanAndReduce(node.getPackageName(), p, r);
aoqi@0 119 r = scanAndReduce(node.getImports(), p, r);
aoqi@0 120 r = scanAndReduce(node.getTypeDecls(), p, r);
aoqi@0 121 return r;
aoqi@0 122 }
aoqi@0 123
aoqi@0 124 public R visitImport(ImportTree node, P p) {
aoqi@0 125 return scan(node.getQualifiedIdentifier(), p);
aoqi@0 126 }
aoqi@0 127
aoqi@0 128 public R visitClass(ClassTree node, P p) {
aoqi@0 129 R r = scan(node.getModifiers(), p);
aoqi@0 130 r = scanAndReduce(node.getTypeParameters(), p, r);
aoqi@0 131 r = scanAndReduce(node.getExtendsClause(), p, r);
aoqi@0 132 r = scanAndReduce(node.getImplementsClause(), p, r);
aoqi@0 133 r = scanAndReduce(node.getMembers(), p, r);
aoqi@0 134 return r;
aoqi@0 135 }
aoqi@0 136
aoqi@0 137 public R visitMethod(MethodTree node, P p) {
aoqi@0 138 R r = scan(node.getModifiers(), p);
aoqi@0 139 r = scanAndReduce(node.getReturnType(), p, r);
aoqi@0 140 r = scanAndReduce(node.getTypeParameters(), p, r);
aoqi@0 141 r = scanAndReduce(node.getParameters(), p, r);
aoqi@0 142 r = scanAndReduce(node.getReceiverParameter(), p, r);
aoqi@0 143 r = scanAndReduce(node.getThrows(), p, r);
aoqi@0 144 r = scanAndReduce(node.getBody(), p, r);
aoqi@0 145 r = scanAndReduce(node.getDefaultValue(), p, r);
aoqi@0 146 return r;
aoqi@0 147 }
aoqi@0 148
aoqi@0 149 public R visitVariable(VariableTree node, P p) {
aoqi@0 150 R r = scan(node.getModifiers(), p);
aoqi@0 151 r = scanAndReduce(node.getType(), p, r);
aoqi@0 152 r = scanAndReduce(node.getNameExpression(), p, r);
aoqi@0 153 r = scanAndReduce(node.getInitializer(), p, r);
aoqi@0 154 return r;
aoqi@0 155 }
aoqi@0 156
aoqi@0 157 public R visitEmptyStatement(EmptyStatementTree node, P p) {
aoqi@0 158 return null;
aoqi@0 159 }
aoqi@0 160
aoqi@0 161 public R visitBlock(BlockTree node, P p) {
aoqi@0 162 return scan(node.getStatements(), p);
aoqi@0 163 }
aoqi@0 164
aoqi@0 165 public R visitDoWhileLoop(DoWhileLoopTree node, P p) {
aoqi@0 166 R r = scan(node.getStatement(), p);
aoqi@0 167 r = scanAndReduce(node.getCondition(), p, r);
aoqi@0 168 return r;
aoqi@0 169 }
aoqi@0 170
aoqi@0 171 public R visitWhileLoop(WhileLoopTree node, P p) {
aoqi@0 172 R r = scan(node.getCondition(), p);
aoqi@0 173 r = scanAndReduce(node.getStatement(), p, r);
aoqi@0 174 return r;
aoqi@0 175 }
aoqi@0 176
aoqi@0 177 public R visitForLoop(ForLoopTree node, P p) {
aoqi@0 178 R r = scan(node.getInitializer(), p);
aoqi@0 179 r = scanAndReduce(node.getCondition(), p, r);
aoqi@0 180 r = scanAndReduce(node.getUpdate(), p, r);
aoqi@0 181 r = scanAndReduce(node.getStatement(), p, r);
aoqi@0 182 return r;
aoqi@0 183 }
aoqi@0 184
aoqi@0 185 public R visitEnhancedForLoop(EnhancedForLoopTree node, P p) {
aoqi@0 186 R r = scan(node.getVariable(), p);
aoqi@0 187 r = scanAndReduce(node.getExpression(), p, r);
aoqi@0 188 r = scanAndReduce(node.getStatement(), p, r);
aoqi@0 189 return r;
aoqi@0 190 }
aoqi@0 191
aoqi@0 192 public R visitLabeledStatement(LabeledStatementTree node, P p) {
aoqi@0 193 return scan(node.getStatement(), p);
aoqi@0 194 }
aoqi@0 195
aoqi@0 196 public R visitSwitch(SwitchTree node, P p) {
aoqi@0 197 R r = scan(node.getExpression(), p);
aoqi@0 198 r = scanAndReduce(node.getCases(), p, r);
aoqi@0 199 return r;
aoqi@0 200 }
aoqi@0 201
aoqi@0 202 public R visitCase(CaseTree node, P p) {
aoqi@0 203 R r = scan(node.getExpression(), p);
aoqi@0 204 r = scanAndReduce(node.getStatements(), p, r);
aoqi@0 205 return r;
aoqi@0 206 }
aoqi@0 207
aoqi@0 208 public R visitSynchronized(SynchronizedTree node, P p) {
aoqi@0 209 R r = scan(node.getExpression(), p);
aoqi@0 210 r = scanAndReduce(node.getBlock(), p, r);
aoqi@0 211 return r;
aoqi@0 212 }
aoqi@0 213
aoqi@0 214 public R visitTry(TryTree node, P p) {
aoqi@0 215 R r = scan(node.getResources(), p);
aoqi@0 216 r = scanAndReduce(node.getBlock(), p, r);
aoqi@0 217 r = scanAndReduce(node.getCatches(), p, r);
aoqi@0 218 r = scanAndReduce(node.getFinallyBlock(), p, r);
aoqi@0 219 return r;
aoqi@0 220 }
aoqi@0 221
aoqi@0 222 public R visitCatch(CatchTree node, P p) {
aoqi@0 223 R r = scan(node.getParameter(), p);
aoqi@0 224 r = scanAndReduce(node.getBlock(), p, r);
aoqi@0 225 return r;
aoqi@0 226 }
aoqi@0 227
aoqi@0 228 public R visitConditionalExpression(ConditionalExpressionTree node, P p) {
aoqi@0 229 R r = scan(node.getCondition(), p);
aoqi@0 230 r = scanAndReduce(node.getTrueExpression(), p, r);
aoqi@0 231 r = scanAndReduce(node.getFalseExpression(), p, r);
aoqi@0 232 return r;
aoqi@0 233 }
aoqi@0 234
aoqi@0 235 public R visitIf(IfTree node, P p) {
aoqi@0 236 R r = scan(node.getCondition(), p);
aoqi@0 237 r = scanAndReduce(node.getThenStatement(), p, r);
aoqi@0 238 r = scanAndReduce(node.getElseStatement(), p, r);
aoqi@0 239 return r;
aoqi@0 240 }
aoqi@0 241
aoqi@0 242 public R visitExpressionStatement(ExpressionStatementTree node, P p) {
aoqi@0 243 return scan(node.getExpression(), p);
aoqi@0 244 }
aoqi@0 245
aoqi@0 246 public R visitBreak(BreakTree node, P p) {
aoqi@0 247 return null;
aoqi@0 248 }
aoqi@0 249
aoqi@0 250 public R visitContinue(ContinueTree node, P p) {
aoqi@0 251 return null;
aoqi@0 252 }
aoqi@0 253
aoqi@0 254 public R visitReturn(ReturnTree node, P p) {
aoqi@0 255 return scan(node.getExpression(), p);
aoqi@0 256 }
aoqi@0 257
aoqi@0 258 public R visitThrow(ThrowTree node, P p) {
aoqi@0 259 return scan(node.getExpression(), p);
aoqi@0 260 }
aoqi@0 261
aoqi@0 262 public R visitAssert(AssertTree node, P p) {
aoqi@0 263 R r = scan(node.getCondition(), p);
aoqi@0 264 r = scanAndReduce(node.getDetail(), p, r);
aoqi@0 265 return r;
aoqi@0 266 }
aoqi@0 267
aoqi@0 268 public R visitMethodInvocation(MethodInvocationTree node, P p) {
aoqi@0 269 R r = scan(node.getTypeArguments(), p);
aoqi@0 270 r = scanAndReduce(node.getMethodSelect(), p, r);
aoqi@0 271 r = scanAndReduce(node.getArguments(), p, r);
aoqi@0 272 return r;
aoqi@0 273 }
aoqi@0 274
aoqi@0 275 public R visitNewClass(NewClassTree node, P p) {
aoqi@0 276 R r = scan(node.getEnclosingExpression(), p);
aoqi@0 277 r = scanAndReduce(node.getIdentifier(), p, r);
aoqi@0 278 r = scanAndReduce(node.getTypeArguments(), p, r);
aoqi@0 279 r = scanAndReduce(node.getArguments(), p, r);
aoqi@0 280 r = scanAndReduce(node.getClassBody(), p, r);
aoqi@0 281 return r;
aoqi@0 282 }
aoqi@0 283
aoqi@0 284 public R visitNewArray(NewArrayTree node, P p) {
aoqi@0 285 R r = scan(node.getType(), p);
aoqi@0 286 r = scanAndReduce(node.getDimensions(), p, r);
aoqi@0 287 r = scanAndReduce(node.getInitializers(), p, r);
aoqi@0 288 r = scanAndReduce(node.getAnnotations(), p, r);
aoqi@0 289 for (Iterable< ? extends Tree> dimAnno : node.getDimAnnotations()) {
aoqi@0 290 r = scanAndReduce(dimAnno, p, r);
aoqi@0 291 }
aoqi@0 292 return r;
aoqi@0 293 }
aoqi@0 294
aoqi@0 295 public R visitLambdaExpression(LambdaExpressionTree node, P p) {
aoqi@0 296 R r = scan(node.getParameters(), p);
aoqi@0 297 r = scanAndReduce(node.getBody(), p, r);
aoqi@0 298 return r;
aoqi@0 299 }
aoqi@0 300
aoqi@0 301 public R visitParenthesized(ParenthesizedTree node, P p) {
aoqi@0 302 return scan(node.getExpression(), p);
aoqi@0 303 }
aoqi@0 304
aoqi@0 305 public R visitAssignment(AssignmentTree node, P p) {
aoqi@0 306 R r = scan(node.getVariable(), p);
aoqi@0 307 r = scanAndReduce(node.getExpression(), p, r);
aoqi@0 308 return r;
aoqi@0 309 }
aoqi@0 310
aoqi@0 311 public R visitCompoundAssignment(CompoundAssignmentTree node, P p) {
aoqi@0 312 R r = scan(node.getVariable(), p);
aoqi@0 313 r = scanAndReduce(node.getExpression(), p, r);
aoqi@0 314 return r;
aoqi@0 315 }
aoqi@0 316
aoqi@0 317 public R visitUnary(UnaryTree node, P p) {
aoqi@0 318 return scan(node.getExpression(), p);
aoqi@0 319 }
aoqi@0 320
aoqi@0 321 public R visitBinary(BinaryTree node, P p) {
aoqi@0 322 R r = scan(node.getLeftOperand(), p);
aoqi@0 323 r = scanAndReduce(node.getRightOperand(), p, r);
aoqi@0 324 return r;
aoqi@0 325 }
aoqi@0 326
aoqi@0 327 public R visitTypeCast(TypeCastTree node, P p) {
aoqi@0 328 R r = scan(node.getType(), p);
aoqi@0 329 r = scanAndReduce(node.getExpression(), p, r);
aoqi@0 330 return r;
aoqi@0 331 }
aoqi@0 332
aoqi@0 333 public R visitInstanceOf(InstanceOfTree node, P p) {
aoqi@0 334 R r = scan(node.getExpression(), p);
aoqi@0 335 r = scanAndReduce(node.getType(), p, r);
aoqi@0 336 return r;
aoqi@0 337 }
aoqi@0 338
aoqi@0 339 public R visitArrayAccess(ArrayAccessTree node, P p) {
aoqi@0 340 R r = scan(node.getExpression(), p);
aoqi@0 341 r = scanAndReduce(node.getIndex(), p, r);
aoqi@0 342 return r;
aoqi@0 343 }
aoqi@0 344
aoqi@0 345 public R visitMemberSelect(MemberSelectTree node, P p) {
aoqi@0 346 return scan(node.getExpression(), p);
aoqi@0 347 }
aoqi@0 348
aoqi@0 349 public R visitMemberReference(MemberReferenceTree node, P p) {
aoqi@0 350 R r = scan(node.getQualifierExpression(), p);
aoqi@0 351 r = scanAndReduce(node.getTypeArguments(), p, r);
aoqi@0 352 return r;
aoqi@0 353 }
aoqi@0 354
aoqi@0 355 public R visitIdentifier(IdentifierTree node, P p) {
aoqi@0 356 return null;
aoqi@0 357 }
aoqi@0 358
aoqi@0 359 public R visitLiteral(LiteralTree node, P p) {
aoqi@0 360 return null;
aoqi@0 361 }
aoqi@0 362
aoqi@0 363 public R visitPrimitiveType(PrimitiveTypeTree node, P p) {
aoqi@0 364 return null;
aoqi@0 365 }
aoqi@0 366
aoqi@0 367 public R visitArrayType(ArrayTypeTree node, P p) {
aoqi@0 368 return scan(node.getType(), p);
aoqi@0 369 }
aoqi@0 370
aoqi@0 371 public R visitParameterizedType(ParameterizedTypeTree node, P p) {
aoqi@0 372 R r = scan(node.getType(), p);
aoqi@0 373 r = scanAndReduce(node.getTypeArguments(), p, r);
aoqi@0 374 return r;
aoqi@0 375 }
aoqi@0 376
aoqi@0 377 public R visitUnionType(UnionTypeTree node, P p) {
aoqi@0 378 return scan(node.getTypeAlternatives(), p);
aoqi@0 379 }
aoqi@0 380
aoqi@0 381 public R visitIntersectionType(IntersectionTypeTree node, P p) {
aoqi@0 382 return scan(node.getBounds(), p);
aoqi@0 383 }
aoqi@0 384
aoqi@0 385 public R visitTypeParameter(TypeParameterTree node, P p) {
aoqi@0 386 R r = scan(node.getAnnotations(), p);
aoqi@0 387 r = scanAndReduce(node.getBounds(), p, r);
aoqi@0 388 return r;
aoqi@0 389 }
aoqi@0 390
aoqi@0 391 public R visitWildcard(WildcardTree node, P p) {
aoqi@0 392 return scan(node.getBound(), p);
aoqi@0 393 }
aoqi@0 394
aoqi@0 395 public R visitModifiers(ModifiersTree node, P p) {
aoqi@0 396 return scan(node.getAnnotations(), p);
aoqi@0 397 }
aoqi@0 398
aoqi@0 399 public R visitAnnotation(AnnotationTree node, P p) {
aoqi@0 400 R r = scan(node.getAnnotationType(), p);
aoqi@0 401 r = scanAndReduce(node.getArguments(), p, r);
aoqi@0 402 return r;
aoqi@0 403 }
aoqi@0 404
aoqi@0 405 public R visitAnnotatedType(AnnotatedTypeTree node, P p) {
aoqi@0 406 R r = scan(node.getAnnotations(), p);
aoqi@0 407 r = scanAndReduce(node.getUnderlyingType(), p, r);
aoqi@0 408 return r;
aoqi@0 409 }
aoqi@0 410
aoqi@0 411 public R visitOther(Tree node, P p) {
aoqi@0 412 return null;
aoqi@0 413 }
aoqi@0 414
aoqi@0 415 public R visitErroneous(ErroneousTree node, P p) {
aoqi@0 416 return null;
aoqi@0 417 }
aoqi@0 418 }

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