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

Sat, 01 Dec 2007 00:00:00 +0000

author
duke
date
Sat, 01 Dec 2007 00:00:00 +0000
changeset 1
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duke@1 1 /*
duke@1 2 * Copyright 2005-2006 Sun Microsystems, Inc. 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
duke@1 7 * published by the Free Software Foundation. Sun designates this
duke@1 8 * particular file as subject to the "Classpath" exception as provided
duke@1 9 * by Sun 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 *
duke@1 21 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
duke@1 22 * CA 95054 USA or visit www.sun.com if you need additional information or
duke@1 23 * have any 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);
duke@1 143 return r;
duke@1 144 }
duke@1 145
duke@1 146 public R visitVariable(VariableTree node, P p) {
duke@1 147 R r = scan(node.getModifiers(), p);
duke@1 148 r = scanAndReduce(node.getType(), p, r);
duke@1 149 r = scanAndReduce(node.getInitializer(), p, r);
duke@1 150 return r;
duke@1 151 }
duke@1 152
duke@1 153 public R visitEmptyStatement(EmptyStatementTree node, P p) {
duke@1 154 return null;
duke@1 155 }
duke@1 156
duke@1 157 public R visitBlock(BlockTree node, P p) {
duke@1 158 return scan(node.getStatements(), p);
duke@1 159 }
duke@1 160
duke@1 161 public R visitDoWhileLoop(DoWhileLoopTree node, P p) {
duke@1 162 R r = scan(node.getStatement(), p);
duke@1 163 r = scanAndReduce(node.getCondition(), p, r);
duke@1 164 return r;
duke@1 165 }
duke@1 166
duke@1 167 public R visitWhileLoop(WhileLoopTree node, P p) {
duke@1 168 R r = scan(node.getCondition(), p);
duke@1 169 r = scanAndReduce(node.getStatement(), p, r);
duke@1 170 return r;
duke@1 171 }
duke@1 172
duke@1 173 public R visitForLoop(ForLoopTree node, P p) {
duke@1 174 R r = scan(node.getInitializer(), p);
duke@1 175 r = scanAndReduce(node.getCondition(), p, r);
duke@1 176 r = scanAndReduce(node.getUpdate(), p, r);
duke@1 177 r = scanAndReduce(node.getStatement(), p, r);
duke@1 178 return r;
duke@1 179 }
duke@1 180
duke@1 181 public R visitEnhancedForLoop(EnhancedForLoopTree node, P p) {
duke@1 182 R r = scan(node.getVariable(), p);
duke@1 183 r = scanAndReduce(node.getExpression(), p, r);
duke@1 184 r = scanAndReduce(node.getStatement(), p, r);
duke@1 185 return r;
duke@1 186 }
duke@1 187
duke@1 188 public R visitLabeledStatement(LabeledStatementTree node, P p) {
duke@1 189 return scan(node.getStatement(), p);
duke@1 190 }
duke@1 191
duke@1 192 public R visitSwitch(SwitchTree node, P p) {
duke@1 193 R r = scan(node.getExpression(), p);
duke@1 194 r = scanAndReduce(node.getCases(), p, r);
duke@1 195 return r;
duke@1 196 }
duke@1 197
duke@1 198 public R visitCase(CaseTree node, P p) {
duke@1 199 R r = scan(node.getExpression(), p);
duke@1 200 r = scanAndReduce(node.getStatements(), p, r);
duke@1 201 return r;
duke@1 202 }
duke@1 203
duke@1 204 public R visitSynchronized(SynchronizedTree node, P p) {
duke@1 205 R r = scan(node.getExpression(), p);
duke@1 206 r = scanAndReduce(node.getBlock(), p, r);
duke@1 207 return r;
duke@1 208 }
duke@1 209
duke@1 210 public R visitTry(TryTree node, P p) {
duke@1 211 R r = scan(node.getBlock(), p);
duke@1 212 r = scanAndReduce(node.getCatches(), p, r);
duke@1 213 r = scanAndReduce(node.getFinallyBlock(), p, r);
duke@1 214 return r;
duke@1 215 }
duke@1 216
duke@1 217 public R visitCatch(CatchTree node, P p) {
duke@1 218 R r = scan(node.getParameter(), p);
duke@1 219 r = scanAndReduce(node.getBlock(), p, r);
duke@1 220 return r;
duke@1 221 }
duke@1 222
duke@1 223 public R visitConditionalExpression(ConditionalExpressionTree node, P p) {
duke@1 224 R r = scan(node.getCondition(), p);
duke@1 225 r = scanAndReduce(node.getTrueExpression(), p, r);
duke@1 226 r = scanAndReduce(node.getFalseExpression(), p, r);
duke@1 227 return r;
duke@1 228 }
duke@1 229
duke@1 230 public R visitIf(IfTree node, P p) {
duke@1 231 R r = scan(node.getCondition(), p);
duke@1 232 r = scanAndReduce(node.getThenStatement(), p, r);
duke@1 233 r = scanAndReduce(node.getElseStatement(), p, r);
duke@1 234 return r;
duke@1 235 }
duke@1 236
duke@1 237 public R visitExpressionStatement(ExpressionStatementTree node, P p) {
duke@1 238 return scan(node.getExpression(), p);
duke@1 239 }
duke@1 240
duke@1 241 public R visitBreak(BreakTree node, P p) {
duke@1 242 return null;
duke@1 243 }
duke@1 244
duke@1 245 public R visitContinue(ContinueTree node, P p) {
duke@1 246 return null;
duke@1 247 }
duke@1 248
duke@1 249 public R visitReturn(ReturnTree node, P p) {
duke@1 250 return scan(node.getExpression(), p);
duke@1 251 }
duke@1 252
duke@1 253 public R visitThrow(ThrowTree node, P p) {
duke@1 254 return scan(node.getExpression(), p);
duke@1 255 }
duke@1 256
duke@1 257 public R visitAssert(AssertTree node, P p) {
duke@1 258 R r = scan(node.getCondition(), p);
duke@1 259 r = scanAndReduce(node.getDetail(), p, r);
duke@1 260 return r;
duke@1 261 }
duke@1 262
duke@1 263 public R visitMethodInvocation(MethodInvocationTree node, P p) {
duke@1 264 R r = scan(node.getTypeArguments(), p);
duke@1 265 r = scanAndReduce(node.getMethodSelect(), p, r);
duke@1 266 r = scanAndReduce(node.getArguments(), p, r);
duke@1 267 return r;
duke@1 268 }
duke@1 269
duke@1 270 public R visitNewClass(NewClassTree node, P p) {
duke@1 271 R r = scan(node.getEnclosingExpression(), p);
duke@1 272 r = scanAndReduce(node.getIdentifier(), p, r);
duke@1 273 r = scanAndReduce(node.getTypeArguments(), p, r);
duke@1 274 r = scanAndReduce(node.getArguments(), p, r);
duke@1 275 r = scanAndReduce(node.getClassBody(), p, r);
duke@1 276 return r;
duke@1 277 }
duke@1 278
duke@1 279 public R visitNewArray(NewArrayTree node, P p) {
duke@1 280 R r = scan(node.getType(), p);
duke@1 281 r = scanAndReduce(node.getDimensions(), p, r);
duke@1 282 r = scanAndReduce(node.getInitializers(), p, r);
duke@1 283 return r;
duke@1 284 }
duke@1 285
duke@1 286 public R visitParenthesized(ParenthesizedTree node, P p) {
duke@1 287 return scan(node.getExpression(), p);
duke@1 288 }
duke@1 289
duke@1 290 public R visitAssignment(AssignmentTree node, P p) {
duke@1 291 R r = scan(node.getVariable(), p);
duke@1 292 r = scanAndReduce(node.getExpression(), p, r);
duke@1 293 return r;
duke@1 294 }
duke@1 295
duke@1 296 public R visitCompoundAssignment(CompoundAssignmentTree node, P p) {
duke@1 297 R r = scan(node.getVariable(), p);
duke@1 298 r = scanAndReduce(node.getExpression(), p, r);
duke@1 299 return r;
duke@1 300 }
duke@1 301
duke@1 302 public R visitUnary(UnaryTree node, P p) {
duke@1 303 return scan(node.getExpression(), p);
duke@1 304 }
duke@1 305
duke@1 306 public R visitBinary(BinaryTree node, P p) {
duke@1 307 R r = scan(node.getLeftOperand(), p);
duke@1 308 r = scanAndReduce(node.getRightOperand(), p, r);
duke@1 309 return r;
duke@1 310 }
duke@1 311
duke@1 312 public R visitTypeCast(TypeCastTree node, P p) {
duke@1 313 R r = scan(node.getType(), p);
duke@1 314 r = scanAndReduce(node.getExpression(), p, r);
duke@1 315 return r;
duke@1 316 }
duke@1 317
duke@1 318 public R visitInstanceOf(InstanceOfTree node, P p) {
duke@1 319 R r = scan(node.getExpression(), p);
duke@1 320 r = scanAndReduce(node.getType(), p, r);
duke@1 321 return r;
duke@1 322 }
duke@1 323
duke@1 324 public R visitArrayAccess(ArrayAccessTree node, P p) {
duke@1 325 R r = scan(node.getExpression(), p);
duke@1 326 r = scanAndReduce(node.getIndex(), p, r);
duke@1 327 return r;
duke@1 328 }
duke@1 329
duke@1 330 public R visitMemberSelect(MemberSelectTree node, P p) {
duke@1 331 return scan(node.getExpression(), p);
duke@1 332 }
duke@1 333
duke@1 334 public R visitIdentifier(IdentifierTree node, P p) {
duke@1 335 return null;
duke@1 336 }
duke@1 337
duke@1 338 public R visitLiteral(LiteralTree node, P p) {
duke@1 339 return null;
duke@1 340 }
duke@1 341
duke@1 342 public R visitPrimitiveType(PrimitiveTypeTree node, P p) {
duke@1 343 return null;
duke@1 344 }
duke@1 345
duke@1 346 public R visitArrayType(ArrayTypeTree node, P p) {
duke@1 347 return scan(node.getType(), p);
duke@1 348 }
duke@1 349
duke@1 350 public R visitParameterizedType(ParameterizedTypeTree node, P p) {
duke@1 351 R r = scan(node.getType(), p);
duke@1 352 r = scanAndReduce(node.getTypeArguments(), p, r);
duke@1 353 return r;
duke@1 354 }
duke@1 355
duke@1 356 public R visitTypeParameter(TypeParameterTree node, P p) {
duke@1 357 return scan(node.getBounds(), p);
duke@1 358 }
duke@1 359
duke@1 360 public R visitWildcard(WildcardTree node, P p) {
duke@1 361 return scan(node.getBound(), p);
duke@1 362 }
duke@1 363
duke@1 364 public R visitModifiers(ModifiersTree node, P p) {
duke@1 365 return scan(node.getAnnotations(), p);
duke@1 366 }
duke@1 367
duke@1 368 public R visitAnnotation(AnnotationTree node, P p) {
duke@1 369 R r = scan(node.getAnnotationType(), p);
duke@1 370 r = scanAndReduce(node.getArguments(), p, r);
duke@1 371 return r;
duke@1 372 }
duke@1 373
duke@1 374 public R visitOther(Tree node, P p) {
duke@1 375 return null;
duke@1 376 }
duke@1 377
duke@1 378 public R visitErroneous(ErroneousTree node, P p) {
duke@1 379 return null;
duke@1 380 }
duke@1 381 }

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