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

Wed, 06 Apr 2011 19:30:57 -0700

author
darcy
date
Wed, 06 Apr 2011 19:30:57 -0700
changeset 969
8cc5b440fdde
parent 815
d17f37522154
child 1142
c896d95e7469
permissions
-rw-r--r--

7033809: Rename "disjunctive" to "union" in javax.lang.model
Reviewed-by: mcimadamore, jjg

duke@1 1 /*
jjg@815 2 * Copyright (c) 2005, 2011, Oracle and/or its affiliates. All rights reserved.
duke@1 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@1 4 *
duke@1 5 * This code is free software; you can redistribute it and/or modify it
duke@1 6 * under the terms of the GNU General Public License version 2 only, as
ohair@554 7 * published by the Free Software Foundation. Oracle designates this
duke@1 8 * particular file as subject to the "Classpath" exception as provided
ohair@554 9 * by Oracle in the LICENSE file that accompanied this code.
duke@1 10 *
duke@1 11 * This code is distributed in the hope that it will be useful, but WITHOUT
duke@1 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@1 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
duke@1 14 * version 2 for more details (a copy is included in the LICENSE file that
duke@1 15 * accompanied this code).
duke@1 16 *
duke@1 17 * You should have received a copy of the GNU General Public License version
duke@1 18 * 2 along with this work; if not, write to the Free Software Foundation,
duke@1 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@1 20 *
ohair@554 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
ohair@554 22 * or visit www.oracle.com if you need additional information or have any
ohair@554 23 * questions.
duke@1 24 */
duke@1 25
duke@1 26 package com.sun.source.util;
duke@1 27
duke@1 28 import com.sun.source.tree.*;
duke@1 29
duke@1 30 /**
duke@1 31 * A TreeVisitor that visits all the child tree nodes.
duke@1 32 * To visit nodes of a particular type, just override the
duke@1 33 * corresponding visitXYZ method.
duke@1 34 * Inside your method, call super.visitXYZ to visit descendant
duke@1 35 * nodes.
duke@1 36 *
duke@1 37 * <p>The default implementation of the visitXYZ methods will determine
duke@1 38 * a result as follows:
duke@1 39 * <ul>
duke@1 40 * <li>If the node being visited has no children, the result will be null.
duke@1 41 * <li>If the node being visited has one child, the result will be the
duke@1 42 * result of calling {@code scan} on that child. The child may be a simple node
duke@1 43 * or itself a list of nodes.
duke@1 44 * <li> If the node being visited has more than one child, the result will
duke@1 45 * be determined by calling {@code scan} each child in turn, and then combining the
duke@1 46 * result of each scan after the first with the cumulative result
duke@1 47 * so far, as determined by the {@link #reduce} method. Each child may be either
duke@1 48 * a simple node of a list of nodes. The default behavior of the {@code reduce}
duke@1 49 * method is such that the result of the visitXYZ method will be the result of
duke@1 50 * the last child scanned.
duke@1 51 * </ul>
duke@1 52 *
duke@1 53 * <p>Here is an example to count the number of identifier nodes in a tree:
duke@1 54 * <pre>
duke@1 55 * class CountIdentifiers extends TreeScanner<Integer,Void> {
duke@1 56 * {@literal @}Override
duke@1 57 * public Integer visitIdentifier(IdentifierTree node, Void p) {
duke@1 58 * return 1;
duke@1 59 * }
duke@1 60 * {@literal @}Override
duke@1 61 * public Integer reduce(Integer r1, Integer r2) {
duke@1 62 * return (r1 == null ? 0 : r1) + (r2 == null ? 0 : r2);
duke@1 63 * }
duke@1 64 * }
duke@1 65 * </pre>
duke@1 66 *
duke@1 67 * @author Peter von der Ah&eacute;
duke@1 68 * @author Jonathan Gibbons
duke@1 69 * @since 1.6
duke@1 70 */
duke@1 71 public class TreeScanner<R,P> implements TreeVisitor<R,P> {
duke@1 72
duke@1 73 /** Scan a single node.
duke@1 74 */
duke@1 75 public R scan(Tree node, P p) {
duke@1 76 return (node == null) ? null : node.accept(this, p);
duke@1 77 }
duke@1 78
duke@1 79 private R scanAndReduce(Tree node, P p, R r) {
duke@1 80 return reduce(scan(node, p), r);
duke@1 81 }
duke@1 82
duke@1 83 /** Scan a list of nodes.
duke@1 84 */
duke@1 85 public R scan(Iterable<? extends Tree> nodes, P p) {
duke@1 86 R r = null;
duke@1 87 if (nodes != null) {
duke@1 88 boolean first = true;
duke@1 89 for (Tree node : nodes) {
duke@1 90 r = (first ? scan(node, p) : scanAndReduce(node, p, r));
duke@1 91 first = false;
duke@1 92 }
duke@1 93 }
duke@1 94 return r;
duke@1 95 }
duke@1 96
duke@1 97 private R scanAndReduce(Iterable<? extends Tree> nodes, P p, R r) {
duke@1 98 return reduce(scan(nodes, p), r);
duke@1 99 }
duke@1 100
duke@1 101 /**
duke@1 102 * Reduces two results into a combined result.
duke@1 103 * The default implementation is to return the first parameter.
duke@1 104 * The general contract of the method is that it may take any action whatsoever.
duke@1 105 */
duke@1 106 public R reduce(R r1, R r2) {
duke@1 107 return r1;
duke@1 108 }
duke@1 109
duke@1 110
duke@1 111 /* ***************************************************************************
duke@1 112 * Visitor methods
duke@1 113 ****************************************************************************/
duke@1 114
duke@1 115 public R visitCompilationUnit(CompilationUnitTree node, P p) {
duke@1 116 R r = scan(node.getPackageAnnotations(), p);
duke@1 117 r = scanAndReduce(node.getPackageName(), p, r);
duke@1 118 r = scanAndReduce(node.getImports(), p, r);
duke@1 119 r = scanAndReduce(node.getTypeDecls(), p, r);
duke@1 120 return r;
duke@1 121 }
duke@1 122
duke@1 123 public R visitImport(ImportTree node, P p) {
duke@1 124 return scan(node.getQualifiedIdentifier(), p);
duke@1 125 }
duke@1 126
duke@1 127 public R visitClass(ClassTree node, P p) {
duke@1 128 R r = scan(node.getModifiers(), p);
duke@1 129 r = scanAndReduce(node.getTypeParameters(), p, r);
duke@1 130 r = scanAndReduce(node.getExtendsClause(), p, r);
duke@1 131 r = scanAndReduce(node.getImplementsClause(), p, r);
duke@1 132 r = scanAndReduce(node.getMembers(), p, r);
duke@1 133 return r;
duke@1 134 }
duke@1 135
duke@1 136 public R visitMethod(MethodTree node, P p) {
duke@1 137 R r = scan(node.getModifiers(), p);
duke@1 138 r = scanAndReduce(node.getReturnType(), p, r);
duke@1 139 r = scanAndReduce(node.getTypeParameters(), p, r);
duke@1 140 r = scanAndReduce(node.getParameters(), p, r);
duke@1 141 r = scanAndReduce(node.getThrows(), p, r);
duke@1 142 r = scanAndReduce(node.getBody(), p, r);
jjg@679 143 r = scanAndReduce(node.getDefaultValue(), p, r);
duke@1 144 return r;
duke@1 145 }
duke@1 146
duke@1 147 public R visitVariable(VariableTree node, P p) {
duke@1 148 R r = scan(node.getModifiers(), p);
duke@1 149 r = scanAndReduce(node.getType(), p, r);
duke@1 150 r = scanAndReduce(node.getInitializer(), p, r);
duke@1 151 return r;
duke@1 152 }
duke@1 153
duke@1 154 public R visitEmptyStatement(EmptyStatementTree node, P p) {
duke@1 155 return null;
duke@1 156 }
duke@1 157
duke@1 158 public R visitBlock(BlockTree node, P p) {
duke@1 159 return scan(node.getStatements(), p);
duke@1 160 }
duke@1 161
duke@1 162 public R visitDoWhileLoop(DoWhileLoopTree node, P p) {
duke@1 163 R r = scan(node.getStatement(), p);
duke@1 164 r = scanAndReduce(node.getCondition(), p, r);
duke@1 165 return r;
duke@1 166 }
duke@1 167
duke@1 168 public R visitWhileLoop(WhileLoopTree node, P p) {
duke@1 169 R r = scan(node.getCondition(), p);
duke@1 170 r = scanAndReduce(node.getStatement(), p, r);
duke@1 171 return r;
duke@1 172 }
duke@1 173
duke@1 174 public R visitForLoop(ForLoopTree node, P p) {
duke@1 175 R r = scan(node.getInitializer(), p);
duke@1 176 r = scanAndReduce(node.getCondition(), p, r);
duke@1 177 r = scanAndReduce(node.getUpdate(), p, r);
duke@1 178 r = scanAndReduce(node.getStatement(), p, r);
duke@1 179 return r;
duke@1 180 }
duke@1 181
duke@1 182 public R visitEnhancedForLoop(EnhancedForLoopTree node, P p) {
duke@1 183 R r = scan(node.getVariable(), p);
duke@1 184 r = scanAndReduce(node.getExpression(), p, r);
duke@1 185 r = scanAndReduce(node.getStatement(), p, r);
duke@1 186 return r;
duke@1 187 }
duke@1 188
duke@1 189 public R visitLabeledStatement(LabeledStatementTree node, P p) {
duke@1 190 return scan(node.getStatement(), p);
duke@1 191 }
duke@1 192
duke@1 193 public R visitSwitch(SwitchTree node, P p) {
duke@1 194 R r = scan(node.getExpression(), p);
duke@1 195 r = scanAndReduce(node.getCases(), p, r);
duke@1 196 return r;
duke@1 197 }
duke@1 198
duke@1 199 public R visitCase(CaseTree node, P p) {
duke@1 200 R r = scan(node.getExpression(), p);
duke@1 201 r = scanAndReduce(node.getStatements(), p, r);
duke@1 202 return r;
duke@1 203 }
duke@1 204
duke@1 205 public R visitSynchronized(SynchronizedTree node, P p) {
duke@1 206 R r = scan(node.getExpression(), p);
duke@1 207 r = scanAndReduce(node.getBlock(), p, r);
duke@1 208 return r;
duke@1 209 }
duke@1 210
duke@1 211 public R visitTry(TryTree node, P p) {
darcy@609 212 R r = scan(node.getResources(), p);
darcy@609 213 r = scanAndReduce(node.getBlock(), p, r);
duke@1 214 r = scanAndReduce(node.getCatches(), p, r);
duke@1 215 r = scanAndReduce(node.getFinallyBlock(), p, r);
duke@1 216 return r;
duke@1 217 }
duke@1 218
duke@1 219 public R visitCatch(CatchTree node, P p) {
duke@1 220 R r = scan(node.getParameter(), p);
duke@1 221 r = scanAndReduce(node.getBlock(), p, r);
duke@1 222 return r;
duke@1 223 }
duke@1 224
duke@1 225 public R visitConditionalExpression(ConditionalExpressionTree node, P p) {
duke@1 226 R r = scan(node.getCondition(), p);
duke@1 227 r = scanAndReduce(node.getTrueExpression(), p, r);
duke@1 228 r = scanAndReduce(node.getFalseExpression(), p, r);
duke@1 229 return r;
duke@1 230 }
duke@1 231
duke@1 232 public R visitIf(IfTree node, P p) {
duke@1 233 R r = scan(node.getCondition(), p);
duke@1 234 r = scanAndReduce(node.getThenStatement(), p, r);
duke@1 235 r = scanAndReduce(node.getElseStatement(), p, r);
duke@1 236 return r;
duke@1 237 }
duke@1 238
duke@1 239 public R visitExpressionStatement(ExpressionStatementTree node, P p) {
duke@1 240 return scan(node.getExpression(), p);
duke@1 241 }
duke@1 242
duke@1 243 public R visitBreak(BreakTree node, P p) {
duke@1 244 return null;
duke@1 245 }
duke@1 246
duke@1 247 public R visitContinue(ContinueTree node, P p) {
duke@1 248 return null;
duke@1 249 }
duke@1 250
duke@1 251 public R visitReturn(ReturnTree node, P p) {
duke@1 252 return scan(node.getExpression(), p);
duke@1 253 }
duke@1 254
duke@1 255 public R visitThrow(ThrowTree node, P p) {
duke@1 256 return scan(node.getExpression(), p);
duke@1 257 }
duke@1 258
duke@1 259 public R visitAssert(AssertTree node, P p) {
duke@1 260 R r = scan(node.getCondition(), p);
duke@1 261 r = scanAndReduce(node.getDetail(), p, r);
duke@1 262 return r;
duke@1 263 }
duke@1 264
duke@1 265 public R visitMethodInvocation(MethodInvocationTree node, P p) {
duke@1 266 R r = scan(node.getTypeArguments(), p);
duke@1 267 r = scanAndReduce(node.getMethodSelect(), p, r);
duke@1 268 r = scanAndReduce(node.getArguments(), p, r);
duke@1 269 return r;
duke@1 270 }
duke@1 271
duke@1 272 public R visitNewClass(NewClassTree node, P p) {
duke@1 273 R r = scan(node.getEnclosingExpression(), p);
duke@1 274 r = scanAndReduce(node.getIdentifier(), p, r);
duke@1 275 r = scanAndReduce(node.getTypeArguments(), p, r);
duke@1 276 r = scanAndReduce(node.getArguments(), p, r);
duke@1 277 r = scanAndReduce(node.getClassBody(), p, r);
duke@1 278 return r;
duke@1 279 }
duke@1 280
duke@1 281 public R visitNewArray(NewArrayTree node, P p) {
duke@1 282 R r = scan(node.getType(), p);
duke@1 283 r = scanAndReduce(node.getDimensions(), p, r);
duke@1 284 r = scanAndReduce(node.getInitializers(), p, r);
duke@1 285 return r;
duke@1 286 }
duke@1 287
duke@1 288 public R visitParenthesized(ParenthesizedTree node, P p) {
duke@1 289 return scan(node.getExpression(), p);
duke@1 290 }
duke@1 291
duke@1 292 public R visitAssignment(AssignmentTree node, P p) {
duke@1 293 R r = scan(node.getVariable(), p);
duke@1 294 r = scanAndReduce(node.getExpression(), p, r);
duke@1 295 return r;
duke@1 296 }
duke@1 297
duke@1 298 public R visitCompoundAssignment(CompoundAssignmentTree node, P p) {
duke@1 299 R r = scan(node.getVariable(), p);
duke@1 300 r = scanAndReduce(node.getExpression(), p, r);
duke@1 301 return r;
duke@1 302 }
duke@1 303
duke@1 304 public R visitUnary(UnaryTree node, P p) {
duke@1 305 return scan(node.getExpression(), p);
duke@1 306 }
duke@1 307
duke@1 308 public R visitBinary(BinaryTree node, P p) {
duke@1 309 R r = scan(node.getLeftOperand(), p);
duke@1 310 r = scanAndReduce(node.getRightOperand(), p, r);
duke@1 311 return r;
duke@1 312 }
duke@1 313
duke@1 314 public R visitTypeCast(TypeCastTree node, P p) {
duke@1 315 R r = scan(node.getType(), p);
duke@1 316 r = scanAndReduce(node.getExpression(), p, r);
duke@1 317 return r;
duke@1 318 }
duke@1 319
duke@1 320 public R visitInstanceOf(InstanceOfTree node, P p) {
duke@1 321 R r = scan(node.getExpression(), p);
duke@1 322 r = scanAndReduce(node.getType(), p, r);
duke@1 323 return r;
duke@1 324 }
duke@1 325
duke@1 326 public R visitArrayAccess(ArrayAccessTree node, P p) {
duke@1 327 R r = scan(node.getExpression(), p);
duke@1 328 r = scanAndReduce(node.getIndex(), p, r);
duke@1 329 return r;
duke@1 330 }
duke@1 331
duke@1 332 public R visitMemberSelect(MemberSelectTree node, P p) {
duke@1 333 return scan(node.getExpression(), p);
duke@1 334 }
duke@1 335
duke@1 336 public R visitIdentifier(IdentifierTree node, P p) {
duke@1 337 return null;
duke@1 338 }
duke@1 339
duke@1 340 public R visitLiteral(LiteralTree node, P p) {
duke@1 341 return null;
duke@1 342 }
duke@1 343
duke@1 344 public R visitPrimitiveType(PrimitiveTypeTree node, P p) {
duke@1 345 return null;
duke@1 346 }
duke@1 347
duke@1 348 public R visitArrayType(ArrayTypeTree node, P p) {
duke@1 349 return scan(node.getType(), p);
duke@1 350 }
duke@1 351
duke@1 352 public R visitParameterizedType(ParameterizedTypeTree node, P p) {
duke@1 353 R r = scan(node.getType(), p);
duke@1 354 r = scanAndReduce(node.getTypeArguments(), p, r);
duke@1 355 return r;
duke@1 356 }
duke@1 357
darcy@969 358 public R visitUnionType(UnionTypeTree node, P p) {
jjg@724 359 return scan(node.getTypeAlternatives(), p);
mcimadamore@550 360 }
mcimadamore@550 361
duke@1 362 public R visitTypeParameter(TypeParameterTree node, P p) {
jjg@722 363 R r = scan(node.getBounds(), p);
jjg@308 364 return r;
duke@1 365 }
duke@1 366
duke@1 367 public R visitWildcard(WildcardTree node, P p) {
duke@1 368 return scan(node.getBound(), p);
duke@1 369 }
duke@1 370
duke@1 371 public R visitModifiers(ModifiersTree node, P p) {
duke@1 372 return scan(node.getAnnotations(), p);
duke@1 373 }
duke@1 374
duke@1 375 public R visitAnnotation(AnnotationTree node, P p) {
duke@1 376 R r = scan(node.getAnnotationType(), p);
duke@1 377 r = scanAndReduce(node.getArguments(), p, r);
duke@1 378 return r;
duke@1 379 }
duke@1 380
duke@1 381 public R visitOther(Tree node, P p) {
duke@1 382 return null;
duke@1 383 }
duke@1 384
duke@1 385 public R visitErroneous(ErroneousTree node, P p) {
duke@1 386 return null;
duke@1 387 }
duke@1 388 }

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