| 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 | */ |
| 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<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> { |
| 72 | |
| 73 | /** Scan a single node. |
| 74 | */ |
| 75 | public R scan(Tree node, P p) { |
| 76 | return (node == null) ? null : node.accept(this, p); |
| 77 | } |
| 78 | |
| 79 | private R scanAndReduce(Tree node, P p, R r) { |
| 80 | return reduce(scan(node, p), r); |
| 81 | } |
| 82 | |
| 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 | } |
| 96 | |
| 97 | private R scanAndReduce(Iterable<? extends Tree> nodes, P p, R r) { |
| 98 | return reduce(scan(nodes, p), r); |
| 99 | } |
| 100 | |
| 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 | } |
| 109 | |
| 110 | |
| 111 | /* *************************************************************************** |
| 112 | * Visitor methods |
| 113 | ****************************************************************************/ |
| 114 | |
| 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 | } |
| 122 | |
| 123 | public R visitImport(ImportTree node, P p) { |
| 124 | return scan(node.getQualifiedIdentifier(), p); |
| 125 | } |
| 126 | |
| 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 | } |
| 135 | |
| 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.getThrows(), p, r); |
| 142 | r = scanAndReduce(node.getBody(), p, r); |
| 143 | return r; |
| 144 | } |
| 145 | |
| 146 | public R visitVariable(VariableTree node, P p) { |
| 147 | R r = scan(node.getModifiers(), p); |
| 148 | r = scanAndReduce(node.getType(), p, r); |
| 149 | r = scanAndReduce(node.getInitializer(), p, r); |
| 150 | return r; |
| 151 | } |
| 152 | |
| 153 | public R visitEmptyStatement(EmptyStatementTree node, P p) { |
| 154 | return null; |
| 155 | } |
| 156 | |
| 157 | public R visitBlock(BlockTree node, P p) { |
| 158 | return scan(node.getStatements(), p); |
| 159 | } |
| 160 | |
| 161 | public R visitDoWhileLoop(DoWhileLoopTree node, P p) { |
| 162 | R r = scan(node.getStatement(), p); |
| 163 | r = scanAndReduce(node.getCondition(), p, r); |
| 164 | return r; |
| 165 | } |
| 166 | |
| 167 | public R visitWhileLoop(WhileLoopTree node, P p) { |
| 168 | R r = scan(node.getCondition(), p); |
| 169 | r = scanAndReduce(node.getStatement(), p, r); |
| 170 | return r; |
| 171 | } |
| 172 | |
| 173 | public R visitForLoop(ForLoopTree node, P p) { |
| 174 | R r = scan(node.getInitializer(), p); |
| 175 | r = scanAndReduce(node.getCondition(), p, r); |
| 176 | r = scanAndReduce(node.getUpdate(), p, r); |
| 177 | r = scanAndReduce(node.getStatement(), p, r); |
| 178 | return r; |
| 179 | } |
| 180 | |
| 181 | public R visitEnhancedForLoop(EnhancedForLoopTree node, P p) { |
| 182 | R r = scan(node.getVariable(), p); |
| 183 | r = scanAndReduce(node.getExpression(), p, r); |
| 184 | r = scanAndReduce(node.getStatement(), p, r); |
| 185 | return r; |
| 186 | } |
| 187 | |
| 188 | public R visitLabeledStatement(LabeledStatementTree node, P p) { |
| 189 | return scan(node.getStatement(), p); |
| 190 | } |
| 191 | |
| 192 | public R visitSwitch(SwitchTree node, P p) { |
| 193 | R r = scan(node.getExpression(), p); |
| 194 | r = scanAndReduce(node.getCases(), p, r); |
| 195 | return r; |
| 196 | } |
| 197 | |
| 198 | public R visitCase(CaseTree node, P p) { |
| 199 | R r = scan(node.getExpression(), p); |
| 200 | r = scanAndReduce(node.getStatements(), p, r); |
| 201 | return r; |
| 202 | } |
| 203 | |
| 204 | public R visitSynchronized(SynchronizedTree node, P p) { |
| 205 | R r = scan(node.getExpression(), p); |
| 206 | r = scanAndReduce(node.getBlock(), p, r); |
| 207 | return r; |
| 208 | } |
| 209 | |
| 210 | public R visitTry(TryTree node, P p) { |
| 211 | R r = scan(node.getBlock(), p); |
| 212 | r = scanAndReduce(node.getCatches(), p, r); |
| 213 | r = scanAndReduce(node.getFinallyBlock(), p, r); |
| 214 | return r; |
| 215 | } |
| 216 | |
| 217 | public R visitCatch(CatchTree node, P p) { |
| 218 | R r = scan(node.getParameter(), p); |
| 219 | r = scanAndReduce(node.getBlock(), p, r); |
| 220 | return r; |
| 221 | } |
| 222 | |
| 223 | public R visitConditionalExpression(ConditionalExpressionTree node, P p) { |
| 224 | R r = scan(node.getCondition(), p); |
| 225 | r = scanAndReduce(node.getTrueExpression(), p, r); |
| 226 | r = scanAndReduce(node.getFalseExpression(), p, r); |
| 227 | return r; |
| 228 | } |
| 229 | |
| 230 | public R visitIf(IfTree node, P p) { |
| 231 | R r = scan(node.getCondition(), p); |
| 232 | r = scanAndReduce(node.getThenStatement(), p, r); |
| 233 | r = scanAndReduce(node.getElseStatement(), p, r); |
| 234 | return r; |
| 235 | } |
| 236 | |
| 237 | public R visitExpressionStatement(ExpressionStatementTree node, P p) { |
| 238 | return scan(node.getExpression(), p); |
| 239 | } |
| 240 | |
| 241 | public R visitBreak(BreakTree node, P p) { |
| 242 | return null; |
| 243 | } |
| 244 | |
| 245 | public R visitContinue(ContinueTree node, P p) { |
| 246 | return null; |
| 247 | } |
| 248 | |
| 249 | public R visitReturn(ReturnTree node, P p) { |
| 250 | return scan(node.getExpression(), p); |
| 251 | } |
| 252 | |
| 253 | public R visitThrow(ThrowTree node, P p) { |
| 254 | return scan(node.getExpression(), p); |
| 255 | } |
| 256 | |
| 257 | public R visitAssert(AssertTree node, P p) { |
| 258 | R r = scan(node.getCondition(), p); |
| 259 | r = scanAndReduce(node.getDetail(), p, r); |
| 260 | return r; |
| 261 | } |
| 262 | |
| 263 | public R visitMethodInvocation(MethodInvocationTree node, P p) { |
| 264 | R r = scan(node.getTypeArguments(), p); |
| 265 | r = scanAndReduce(node.getMethodSelect(), p, r); |
| 266 | r = scanAndReduce(node.getArguments(), p, r); |
| 267 | return r; |
| 268 | } |
| 269 | |
| 270 | public R visitNewClass(NewClassTree node, P p) { |
| 271 | R r = scan(node.getEnclosingExpression(), p); |
| 272 | r = scanAndReduce(node.getIdentifier(), p, r); |
| 273 | r = scanAndReduce(node.getTypeArguments(), p, r); |
| 274 | r = scanAndReduce(node.getArguments(), p, r); |
| 275 | r = scanAndReduce(node.getClassBody(), p, r); |
| 276 | return r; |
| 277 | } |
| 278 | |
| 279 | public R visitNewArray(NewArrayTree node, P p) { |
| 280 | R r = scan(node.getType(), p); |
| 281 | r = scanAndReduce(node.getDimensions(), p, r); |
| 282 | r = scanAndReduce(node.getInitializers(), p, r); |
| 283 | return r; |
| 284 | } |
| 285 | |
| 286 | public R visitParenthesized(ParenthesizedTree node, P p) { |
| 287 | return scan(node.getExpression(), p); |
| 288 | } |
| 289 | |
| 290 | public R visitAssignment(AssignmentTree node, P p) { |
| 291 | R r = scan(node.getVariable(), p); |
| 292 | r = scanAndReduce(node.getExpression(), p, r); |
| 293 | return r; |
| 294 | } |
| 295 | |
| 296 | public R visitCompoundAssignment(CompoundAssignmentTree node, P p) { |
| 297 | R r = scan(node.getVariable(), p); |
| 298 | r = scanAndReduce(node.getExpression(), p, r); |
| 299 | return r; |
| 300 | } |
| 301 | |
| 302 | public R visitUnary(UnaryTree node, P p) { |
| 303 | return scan(node.getExpression(), p); |
| 304 | } |
| 305 | |
| 306 | public R visitBinary(BinaryTree node, P p) { |
| 307 | R r = scan(node.getLeftOperand(), p); |
| 308 | r = scanAndReduce(node.getRightOperand(), p, r); |
| 309 | return r; |
| 310 | } |
| 311 | |
| 312 | public R visitTypeCast(TypeCastTree node, P p) { |
| 313 | R r = scan(node.getType(), p); |
| 314 | r = scanAndReduce(node.getExpression(), p, r); |
| 315 | return r; |
| 316 | } |
| 317 | |
| 318 | public R visitInstanceOf(InstanceOfTree node, P p) { |
| 319 | R r = scan(node.getExpression(), p); |
| 320 | r = scanAndReduce(node.getType(), p, r); |
| 321 | return r; |
| 322 | } |
| 323 | |
| 324 | public R visitArrayAccess(ArrayAccessTree node, P p) { |
| 325 | R r = scan(node.getExpression(), p); |
| 326 | r = scanAndReduce(node.getIndex(), p, r); |
| 327 | return r; |
| 328 | } |
| 329 | |
| 330 | public R visitMemberSelect(MemberSelectTree node, P p) { |
| 331 | return scan(node.getExpression(), p); |
| 332 | } |
| 333 | |
| 334 | public R visitIdentifier(IdentifierTree node, P p) { |
| 335 | return null; |
| 336 | } |
| 337 | |
| 338 | public R visitLiteral(LiteralTree node, P p) { |
| 339 | return null; |
| 340 | } |
| 341 | |
| 342 | public R visitPrimitiveType(PrimitiveTypeTree node, P p) { |
| 343 | return null; |
| 344 | } |
| 345 | |
| 346 | public R visitArrayType(ArrayTypeTree node, P p) { |
| 347 | return scan(node.getType(), p); |
| 348 | } |
| 349 | |
| 350 | public R visitParameterizedType(ParameterizedTypeTree node, P p) { |
| 351 | R r = scan(node.getType(), p); |
| 352 | r = scanAndReduce(node.getTypeArguments(), p, r); |
| 353 | return r; |
| 354 | } |
| 355 | |
| 356 | public R visitTypeParameter(TypeParameterTree node, P p) { |
| 357 | return scan(node.getBounds(), p); |
| 358 | } |
| 359 | |
| 360 | public R visitWildcard(WildcardTree node, P p) { |
| 361 | return scan(node.getBound(), p); |
| 362 | } |
| 363 | |
| 364 | public R visitModifiers(ModifiersTree node, P p) { |
| 365 | return scan(node.getAnnotations(), p); |
| 366 | } |
| 367 | |
| 368 | public R visitAnnotation(AnnotationTree node, P p) { |
| 369 | R r = scan(node.getAnnotationType(), p); |
| 370 | r = scanAndReduce(node.getArguments(), p, r); |
| 371 | return r; |
| 372 | } |
| 373 | |
| 374 | public R visitOther(Tree node, P p) { |
| 375 | return null; |
| 376 | } |
| 377 | |
| 378 | public R visitErroneous(ErroneousTree node, P p) { |
| 379 | return null; |
| 380 | } |
| 381 | } |