| /* |
| * Copyright (c) 2005, 2006, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package com.sun.source.util; |
| |
| import com.sun.source.tree.*; |
| |
| /** |
| * A TreeVisitor that visits all the child tree nodes. |
| * To visit nodes of a particular type, just override the |
| * corresponding visitXYZ method. |
| * Inside your method, call super.visitXYZ to visit descendant |
| * nodes. |
| * |
| * <p>The default implementation of the visitXYZ methods will determine |
| * a result as follows: |
| * <ul> |
| * <li>If the node being visited has no children, the result will be null. |
| * <li>If the node being visited has one child, the result will be the |
| * result of calling {@code scan} on that child. The child may be a simple node |
| * or itself a list of nodes. |
| * <li> If the node being visited has more than one child, the result will |
| * be determined by calling {@code scan} each child in turn, and then combining the |
| * result of each scan after the first with the cumulative result |
| * so far, as determined by the {@link #reduce} method. Each child may be either |
| * a simple node of a list of nodes. The default behavior of the {@code reduce} |
| * method is such that the result of the visitXYZ method will be the result of |
| * the last child scanned. |
| * </ul> |
| * |
| * <p>Here is an example to count the number of identifier nodes in a tree: |
| * <pre> |
| * class CountIdentifiers extends TreeScanner<Integer,Void> { |
| * {@literal @}Override |
| * public Integer visitIdentifier(IdentifierTree node, Void p) { |
| * return 1; |
| * } |
| * {@literal @}Override |
| * public Integer reduce(Integer r1, Integer r2) { |
| * return (r1 == null ? 0 : r1) + (r2 == null ? 0 : r2); |
| * } |
| * } |
| * </pre> |
| * |
| * @author Peter von der Ahé |
| * @author Jonathan Gibbons |
| * @since 1.6 |
| */ |
| public class TreeScanner<R,P> implements TreeVisitor<R,P> { |
| |
| /** Scan a single node. |
| */ |
| public R scan(Tree node, P p) { |
| return (node == null) ? null : node.accept(this, p); |
| } |
| |
| private R scanAndReduce(Tree node, P p, R r) { |
| return reduce(scan(node, p), r); |
| } |
| |
| /** Scan a list of nodes. |
| */ |
| public R scan(Iterable<? extends Tree> nodes, P p) { |
| R r = null; |
| if (nodes != null) { |
| boolean first = true; |
| for (Tree node : nodes) { |
| r = (first ? scan(node, p) : scanAndReduce(node, p, r)); |
| first = false; |
| } |
| } |
| return r; |
| } |
| |
| private R scanAndReduce(Iterable<? extends Tree> nodes, P p, R r) { |
| return reduce(scan(nodes, p), r); |
| } |
| |
| /** |
| * Reduces two results into a combined result. |
| * The default implementation is to return the first parameter. |
| * The general contract of the method is that it may take any action whatsoever. |
| */ |
| public R reduce(R r1, R r2) { |
| return r1; |
| } |
| |
| |
| /* *************************************************************************** |
| * Visitor methods |
| ****************************************************************************/ |
| |
| public R visitCompilationUnit(CompilationUnitTree node, P p) { |
| R r = scan(node.getPackageAnnotations(), p); |
| r = scanAndReduce(node.getPackageName(), p, r); |
| r = scanAndReduce(node.getImports(), p, r); |
| r = scanAndReduce(node.getTypeDecls(), p, r); |
| return r; |
| } |
| |
| public R visitImport(ImportTree node, P p) { |
| return scan(node.getQualifiedIdentifier(), p); |
| } |
| |
| public R visitClass(ClassTree node, P p) { |
| R r = scan(node.getModifiers(), p); |
| r = scanAndReduce(node.getTypeParameters(), p, r); |
| r = scanAndReduce(node.getExtendsClause(), p, r); |
| r = scanAndReduce(node.getImplementsClause(), p, r); |
| r = scanAndReduce(node.getMembers(), p, r); |
| return r; |
| } |
| |
| public R visitMethod(MethodTree node, P p) { |
| R r = scan(node.getModifiers(), p); |
| r = scanAndReduce(node.getReturnType(), p, r); |
| r = scanAndReduce(node.getTypeParameters(), p, r); |
| r = scanAndReduce(node.getParameters(), p, r); |
| r = scanAndReduce(node.getReceiverAnnotations(), p, r); |
| r = scanAndReduce(node.getThrows(), p, r); |
| r = scanAndReduce(node.getBody(), p, r); |
| return r; |
| } |
| |
| public R visitVariable(VariableTree node, P p) { |
| R r = scan(node.getModifiers(), p); |
| r = scanAndReduce(node.getType(), p, r); |
| r = scanAndReduce(node.getInitializer(), p, r); |
| return r; |
| } |
| |
| public R visitEmptyStatement(EmptyStatementTree node, P p) { |
| return null; |
| } |
| |
| public R visitBlock(BlockTree node, P p) { |
| return scan(node.getStatements(), p); |
| } |
| |
| public R visitDoWhileLoop(DoWhileLoopTree node, P p) { |
| R r = scan(node.getStatement(), p); |
| r = scanAndReduce(node.getCondition(), p, r); |
| return r; |
| } |
| |
| public R visitWhileLoop(WhileLoopTree node, P p) { |
| R r = scan(node.getCondition(), p); |
| r = scanAndReduce(node.getStatement(), p, r); |
| return r; |
| } |
| |
| public R visitForLoop(ForLoopTree node, P p) { |
| R r = scan(node.getInitializer(), p); |
| r = scanAndReduce(node.getCondition(), p, r); |
| r = scanAndReduce(node.getUpdate(), p, r); |
| r = scanAndReduce(node.getStatement(), p, r); |
| return r; |
| } |
| |
| public R visitEnhancedForLoop(EnhancedForLoopTree node, P p) { |
| R r = scan(node.getVariable(), p); |
| r = scanAndReduce(node.getExpression(), p, r); |
| r = scanAndReduce(node.getStatement(), p, r); |
| return r; |
| } |
| |
| public R visitLabeledStatement(LabeledStatementTree node, P p) { |
| return scan(node.getStatement(), p); |
| } |
| |
| public R visitSwitch(SwitchTree node, P p) { |
| R r = scan(node.getExpression(), p); |
| r = scanAndReduce(node.getCases(), p, r); |
| return r; |
| } |
| |
| public R visitCase(CaseTree node, P p) { |
| R r = scan(node.getExpression(), p); |
| r = scanAndReduce(node.getStatements(), p, r); |
| return r; |
| } |
| |
| public R visitSynchronized(SynchronizedTree node, P p) { |
| R r = scan(node.getExpression(), p); |
| r = scanAndReduce(node.getBlock(), p, r); |
| return r; |
| } |
| |
| public R visitTry(TryTree node, P p) { |
| R r = scan(node.getBlock(), p); |
| r = scanAndReduce(node.getCatches(), p, r); |
| r = scanAndReduce(node.getFinallyBlock(), p, r); |
| return r; |
| } |
| |
| public R visitCatch(CatchTree node, P p) { |
| R r = scan(node.getParameter(), p); |
| r = scanAndReduce(node.getBlock(), p, r); |
| return r; |
| } |
| |
| public R visitConditionalExpression(ConditionalExpressionTree node, P p) { |
| R r = scan(node.getCondition(), p); |
| r = scanAndReduce(node.getTrueExpression(), p, r); |
| r = scanAndReduce(node.getFalseExpression(), p, r); |
| return r; |
| } |
| |
| public R visitIf(IfTree node, P p) { |
| R r = scan(node.getCondition(), p); |
| r = scanAndReduce(node.getThenStatement(), p, r); |
| r = scanAndReduce(node.getElseStatement(), p, r); |
| return r; |
| } |
| |
| public R visitExpressionStatement(ExpressionStatementTree node, P p) { |
| return scan(node.getExpression(), p); |
| } |
| |
| public R visitBreak(BreakTree node, P p) { |
| return null; |
| } |
| |
| public R visitContinue(ContinueTree node, P p) { |
| return null; |
| } |
| |
| public R visitReturn(ReturnTree node, P p) { |
| return scan(node.getExpression(), p); |
| } |
| |
| public R visitThrow(ThrowTree node, P p) { |
| return scan(node.getExpression(), p); |
| } |
| |
| public R visitAssert(AssertTree node, P p) { |
| R r = scan(node.getCondition(), p); |
| r = scanAndReduce(node.getDetail(), p, r); |
| return r; |
| } |
| |
| public R visitMethodInvocation(MethodInvocationTree node, P p) { |
| R r = scan(node.getTypeArguments(), p); |
| r = scanAndReduce(node.getMethodSelect(), p, r); |
| r = scanAndReduce(node.getArguments(), p, r); |
| return r; |
| } |
| |
| public R visitNewClass(NewClassTree node, P p) { |
| R r = scan(node.getEnclosingExpression(), p); |
| r = scanAndReduce(node.getIdentifier(), p, r); |
| r = scanAndReduce(node.getTypeArguments(), p, r); |
| r = scanAndReduce(node.getArguments(), p, r); |
| r = scanAndReduce(node.getClassBody(), p, r); |
| return r; |
| } |
| |
| public R visitNewArray(NewArrayTree node, P p) { |
| R r = scan(node.getType(), p); |
| r = scanAndReduce(node.getDimensions(), p, r); |
| r = scanAndReduce(node.getInitializers(), p, r); |
| return r; |
| } |
| |
| public R visitParenthesized(ParenthesizedTree node, P p) { |
| return scan(node.getExpression(), p); |
| } |
| |
| public R visitAssignment(AssignmentTree node, P p) { |
| R r = scan(node.getVariable(), p); |
| r = scanAndReduce(node.getExpression(), p, r); |
| return r; |
| } |
| |
| public R visitCompoundAssignment(CompoundAssignmentTree node, P p) { |
| R r = scan(node.getVariable(), p); |
| r = scanAndReduce(node.getExpression(), p, r); |
| return r; |
| } |
| |
| public R visitUnary(UnaryTree node, P p) { |
| return scan(node.getExpression(), p); |
| } |
| |
| public R visitBinary(BinaryTree node, P p) { |
| R r = scan(node.getLeftOperand(), p); |
| r = scanAndReduce(node.getRightOperand(), p, r); |
| return r; |
| } |
| |
| public R visitTypeCast(TypeCastTree node, P p) { |
| R r = scan(node.getType(), p); |
| r = scanAndReduce(node.getExpression(), p, r); |
| return r; |
| } |
| |
| public R visitInstanceOf(InstanceOfTree node, P p) { |
| R r = scan(node.getExpression(), p); |
| r = scanAndReduce(node.getType(), p, r); |
| return r; |
| } |
| |
| public R visitArrayAccess(ArrayAccessTree node, P p) { |
| R r = scan(node.getExpression(), p); |
| r = scanAndReduce(node.getIndex(), p, r); |
| return r; |
| } |
| |
| public R visitMemberSelect(MemberSelectTree node, P p) { |
| return scan(node.getExpression(), p); |
| } |
| |
| public R visitIdentifier(IdentifierTree node, P p) { |
| return null; |
| } |
| |
| public R visitLiteral(LiteralTree node, P p) { |
| return null; |
| } |
| |
| public R visitPrimitiveType(PrimitiveTypeTree node, P p) { |
| return null; |
| } |
| |
| public R visitArrayType(ArrayTypeTree node, P p) { |
| return scan(node.getType(), p); |
| } |
| |
| public R visitParameterizedType(ParameterizedTypeTree node, P p) { |
| R r = scan(node.getType(), p); |
| r = scanAndReduce(node.getTypeArguments(), p, r); |
| return r; |
| } |
| |
| public R visitDisjointType(DisjointTypeTree node, P p) { |
| return scan(node.getTypeComponents(), p); |
| } |
| |
| public R visitTypeParameter(TypeParameterTree node, P p) { |
| R r = scan(node.getAnnotations(), p); |
| r = scanAndReduce(node.getBounds(), p, r); |
| return r; |
| } |
| |
| public R visitWildcard(WildcardTree node, P p) { |
| return scan(node.getBound(), p); |
| } |
| |
| public R visitModifiers(ModifiersTree node, P p) { |
| return scan(node.getAnnotations(), p); |
| } |
| |
| public R visitAnnotation(AnnotationTree node, P p) { |
| R r = scan(node.getAnnotationType(), p); |
| r = scanAndReduce(node.getArguments(), p, r); |
| return r; |
| } |
| |
| public R visitAnnotatedType(AnnotatedTypeTree node, P p) { |
| R r = scan(node.getAnnotations(), p); |
| r = scanAndReduce(node.getUnderlyingType(), p, r); |
| return r; |
| } |
| |
| public R visitOther(Tree node, P p) { |
| return null; |
| } |
| |
| public R visitErroneous(ErroneousTree node, P p) { |
| return null; |
| } |
| } |