duke@1: /*
jjg@1521: * Copyright (c) 2005, 2013, Oracle and/or its affiliates. All rights reserved.
duke@1: * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@1: *
duke@1: * This code is free software; you can redistribute it and/or modify it
duke@1: * under the terms of the GNU General Public License version 2 only, as
ohair@554: * published by the Free Software Foundation. Oracle designates this
duke@1: * particular file as subject to the "Classpath" exception as provided
ohair@554: * by Oracle in the LICENSE file that accompanied this code.
duke@1: *
duke@1: * This code is distributed in the hope that it will be useful, but WITHOUT
duke@1: * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@1: * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
duke@1: * version 2 for more details (a copy is included in the LICENSE file that
duke@1: * accompanied this code).
duke@1: *
duke@1: * You should have received a copy of the GNU General Public License version
duke@1: * 2 along with this work; if not, write to the Free Software Foundation,
duke@1: * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@1: *
ohair@554: * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
ohair@554: * or visit www.oracle.com if you need additional information or have any
ohair@554: * questions.
duke@1: */
duke@1:
duke@1: package com.sun.source.util;
duke@1:
duke@1: import com.sun.source.tree.*;
duke@1:
duke@1: /**
duke@1: * A TreeVisitor that visits all the child tree nodes.
duke@1: * To visit nodes of a particular type, just override the
duke@1: * corresponding visitXYZ method.
duke@1: * Inside your method, call super.visitXYZ to visit descendant
duke@1: * nodes.
duke@1: *
duke@1: *
The default implementation of the visitXYZ methods will determine
duke@1: * a result as follows:
duke@1: *
duke@1: * - If the node being visited has no children, the result will be null.
duke@1: *
- If the node being visited has one child, the result will be the
duke@1: * result of calling {@code scan} on that child. The child may be a simple node
duke@1: * or itself a list of nodes.
duke@1: *
- If the node being visited has more than one child, the result will
duke@1: * be determined by calling {@code scan} each child in turn, and then combining the
duke@1: * result of each scan after the first with the cumulative result
duke@1: * so far, as determined by the {@link #reduce} method. Each child may be either
duke@1: * a simple node of a list of nodes. The default behavior of the {@code reduce}
duke@1: * method is such that the result of the visitXYZ method will be the result of
duke@1: * the last child scanned.
duke@1: *
duke@1: *
duke@1: * Here is an example to count the number of identifier nodes in a tree:
duke@1: *
jjg@1326: * class CountIdentifiers extends TreeScanner<Integer,Void> {
duke@1: * {@literal @}Override
duke@1: * public Integer visitIdentifier(IdentifierTree node, Void p) {
duke@1: * return 1;
duke@1: * }
duke@1: * {@literal @}Override
duke@1: * public Integer reduce(Integer r1, Integer r2) {
duke@1: * return (r1 == null ? 0 : r1) + (r2 == null ? 0 : r2);
duke@1: * }
duke@1: * }
duke@1: *
duke@1: *
duke@1: * @author Peter von der Ahé
duke@1: * @author Jonathan Gibbons
duke@1: * @since 1.6
duke@1: */
darcy@2083: @jdk.Exported
duke@1: public class TreeScanner implements TreeVisitor {
duke@1:
duke@1: /** Scan a single node.
duke@1: */
duke@1: public R scan(Tree node, P p) {
duke@1: return (node == null) ? null : node.accept(this, p);
duke@1: }
duke@1:
duke@1: private R scanAndReduce(Tree node, P p, R r) {
duke@1: return reduce(scan(node, p), r);
duke@1: }
duke@1:
duke@1: /** Scan a list of nodes.
duke@1: */
duke@1: public R scan(Iterable extends Tree> nodes, P p) {
duke@1: R r = null;
duke@1: if (nodes != null) {
duke@1: boolean first = true;
duke@1: for (Tree node : nodes) {
duke@1: r = (first ? scan(node, p) : scanAndReduce(node, p, r));
duke@1: first = false;
duke@1: }
duke@1: }
duke@1: return r;
duke@1: }
duke@1:
duke@1: private R scanAndReduce(Iterable extends Tree> nodes, P p, R r) {
duke@1: return reduce(scan(nodes, p), r);
duke@1: }
duke@1:
duke@1: /**
duke@1: * Reduces two results into a combined result.
duke@1: * The default implementation is to return the first parameter.
duke@1: * The general contract of the method is that it may take any action whatsoever.
duke@1: */
duke@1: public R reduce(R r1, R r2) {
duke@1: return r1;
duke@1: }
duke@1:
duke@1:
duke@1: /* ***************************************************************************
duke@1: * Visitor methods
duke@1: ****************************************************************************/
duke@1:
duke@1: public R visitCompilationUnit(CompilationUnitTree node, P p) {
duke@1: R r = scan(node.getPackageAnnotations(), p);
duke@1: r = scanAndReduce(node.getPackageName(), p, r);
duke@1: r = scanAndReduce(node.getImports(), p, r);
duke@1: r = scanAndReduce(node.getTypeDecls(), p, r);
duke@1: return r;
duke@1: }
duke@1:
duke@1: public R visitImport(ImportTree node, P p) {
duke@1: return scan(node.getQualifiedIdentifier(), p);
duke@1: }
duke@1:
duke@1: public R visitClass(ClassTree node, P p) {
duke@1: R r = scan(node.getModifiers(), p);
duke@1: r = scanAndReduce(node.getTypeParameters(), p, r);
duke@1: r = scanAndReduce(node.getExtendsClause(), p, r);
duke@1: r = scanAndReduce(node.getImplementsClause(), p, r);
duke@1: r = scanAndReduce(node.getMembers(), p, r);
duke@1: return r;
duke@1: }
duke@1:
duke@1: public R visitMethod(MethodTree node, P p) {
duke@1: R r = scan(node.getModifiers(), p);
duke@1: r = scanAndReduce(node.getReturnType(), p, r);
duke@1: r = scanAndReduce(node.getTypeParameters(), p, r);
duke@1: r = scanAndReduce(node.getParameters(), p, r);
jjg@1521: r = scanAndReduce(node.getReceiverParameter(), p, r);
duke@1: r = scanAndReduce(node.getThrows(), p, r);
duke@1: r = scanAndReduce(node.getBody(), p, r);
jjg@679: r = scanAndReduce(node.getDefaultValue(), p, r);
duke@1: return r;
duke@1: }
duke@1:
duke@1: public R visitVariable(VariableTree node, P p) {
duke@1: R r = scan(node.getModifiers(), p);
duke@1: r = scanAndReduce(node.getType(), p, r);
jjg@1757: r = scanAndReduce(node.getNameExpression(), p, r);
duke@1: r = scanAndReduce(node.getInitializer(), p, r);
duke@1: return r;
duke@1: }
duke@1:
duke@1: public R visitEmptyStatement(EmptyStatementTree node, P p) {
duke@1: return null;
duke@1: }
duke@1:
duke@1: public R visitBlock(BlockTree node, P p) {
duke@1: return scan(node.getStatements(), p);
duke@1: }
duke@1:
duke@1: public R visitDoWhileLoop(DoWhileLoopTree node, P p) {
duke@1: R r = scan(node.getStatement(), p);
duke@1: r = scanAndReduce(node.getCondition(), p, r);
duke@1: return r;
duke@1: }
duke@1:
duke@1: public R visitWhileLoop(WhileLoopTree node, P p) {
duke@1: R r = scan(node.getCondition(), p);
duke@1: r = scanAndReduce(node.getStatement(), p, r);
duke@1: return r;
duke@1: }
duke@1:
duke@1: public R visitForLoop(ForLoopTree node, P p) {
duke@1: R r = scan(node.getInitializer(), p);
duke@1: r = scanAndReduce(node.getCondition(), p, r);
duke@1: r = scanAndReduce(node.getUpdate(), p, r);
duke@1: r = scanAndReduce(node.getStatement(), p, r);
duke@1: return r;
duke@1: }
duke@1:
duke@1: public R visitEnhancedForLoop(EnhancedForLoopTree node, P p) {
duke@1: R r = scan(node.getVariable(), p);
duke@1: r = scanAndReduce(node.getExpression(), p, r);
duke@1: r = scanAndReduce(node.getStatement(), p, r);
duke@1: return r;
duke@1: }
duke@1:
duke@1: public R visitLabeledStatement(LabeledStatementTree node, P p) {
duke@1: return scan(node.getStatement(), p);
duke@1: }
duke@1:
duke@1: public R visitSwitch(SwitchTree node, P p) {
duke@1: R r = scan(node.getExpression(), p);
duke@1: r = scanAndReduce(node.getCases(), p, r);
duke@1: return r;
duke@1: }
duke@1:
duke@1: public R visitCase(CaseTree node, P p) {
duke@1: R r = scan(node.getExpression(), p);
duke@1: r = scanAndReduce(node.getStatements(), p, r);
duke@1: return r;
duke@1: }
duke@1:
duke@1: public R visitSynchronized(SynchronizedTree node, P p) {
duke@1: R r = scan(node.getExpression(), p);
duke@1: r = scanAndReduce(node.getBlock(), p, r);
duke@1: return r;
duke@1: }
duke@1:
duke@1: public R visitTry(TryTree node, P p) {
darcy@609: R r = scan(node.getResources(), p);
darcy@609: r = scanAndReduce(node.getBlock(), p, r);
duke@1: r = scanAndReduce(node.getCatches(), p, r);
duke@1: r = scanAndReduce(node.getFinallyBlock(), p, r);
duke@1: return r;
duke@1: }
duke@1:
duke@1: public R visitCatch(CatchTree node, P p) {
duke@1: R r = scan(node.getParameter(), p);
duke@1: r = scanAndReduce(node.getBlock(), p, r);
duke@1: return r;
duke@1: }
duke@1:
duke@1: public R visitConditionalExpression(ConditionalExpressionTree node, P p) {
duke@1: R r = scan(node.getCondition(), p);
duke@1: r = scanAndReduce(node.getTrueExpression(), p, r);
duke@1: r = scanAndReduce(node.getFalseExpression(), p, r);
duke@1: return r;
duke@1: }
duke@1:
duke@1: public R visitIf(IfTree node, P p) {
duke@1: R r = scan(node.getCondition(), p);
duke@1: r = scanAndReduce(node.getThenStatement(), p, r);
duke@1: r = scanAndReduce(node.getElseStatement(), p, r);
duke@1: return r;
duke@1: }
duke@1:
duke@1: public R visitExpressionStatement(ExpressionStatementTree node, P p) {
duke@1: return scan(node.getExpression(), p);
duke@1: }
duke@1:
duke@1: public R visitBreak(BreakTree node, P p) {
duke@1: return null;
duke@1: }
duke@1:
duke@1: public R visitContinue(ContinueTree node, P p) {
duke@1: return null;
duke@1: }
duke@1:
duke@1: public R visitReturn(ReturnTree node, P p) {
duke@1: return scan(node.getExpression(), p);
duke@1: }
duke@1:
duke@1: public R visitThrow(ThrowTree node, P p) {
duke@1: return scan(node.getExpression(), p);
duke@1: }
duke@1:
duke@1: public R visitAssert(AssertTree node, P p) {
duke@1: R r = scan(node.getCondition(), p);
duke@1: r = scanAndReduce(node.getDetail(), p, r);
duke@1: return r;
duke@1: }
duke@1:
duke@1: public R visitMethodInvocation(MethodInvocationTree node, P p) {
duke@1: R r = scan(node.getTypeArguments(), p);
duke@1: r = scanAndReduce(node.getMethodSelect(), p, r);
duke@1: r = scanAndReduce(node.getArguments(), p, r);
duke@1: return r;
duke@1: }
duke@1:
duke@1: public R visitNewClass(NewClassTree node, P p) {
duke@1: R r = scan(node.getEnclosingExpression(), p);
duke@1: r = scanAndReduce(node.getIdentifier(), p, r);
duke@1: r = scanAndReduce(node.getTypeArguments(), p, r);
duke@1: r = scanAndReduce(node.getArguments(), p, r);
duke@1: r = scanAndReduce(node.getClassBody(), p, r);
duke@1: return r;
duke@1: }
duke@1:
duke@1: public R visitNewArray(NewArrayTree node, P p) {
duke@1: R r = scan(node.getType(), p);
duke@1: r = scanAndReduce(node.getDimensions(), p, r);
duke@1: r = scanAndReduce(node.getInitializers(), p, r);
vromero@1944: r = scanAndReduce(node.getAnnotations(), p, r);
vromero@1944: for (Iterable< ? extends Tree> dimAnno : node.getDimAnnotations()) {
vromero@1944: r = scanAndReduce(dimAnno, p, r);
vromero@1944: }
duke@1: return r;
duke@1: }
duke@1:
mcimadamore@1142: public R visitLambdaExpression(LambdaExpressionTree node, P p) {
mcimadamore@1142: R r = scan(node.getParameters(), p);
mcimadamore@1142: r = scanAndReduce(node.getBody(), p, r);
mcimadamore@1142: return r;
mcimadamore@1142: }
mcimadamore@1142:
duke@1: public R visitParenthesized(ParenthesizedTree node, P p) {
duke@1: return scan(node.getExpression(), p);
duke@1: }
duke@1:
duke@1: public R visitAssignment(AssignmentTree node, P p) {
duke@1: R r = scan(node.getVariable(), p);
duke@1: r = scanAndReduce(node.getExpression(), p, r);
duke@1: return r;
duke@1: }
duke@1:
duke@1: public R visitCompoundAssignment(CompoundAssignmentTree node, P p) {
duke@1: R r = scan(node.getVariable(), p);
duke@1: r = scanAndReduce(node.getExpression(), p, r);
duke@1: return r;
duke@1: }
duke@1:
duke@1: public R visitUnary(UnaryTree node, P p) {
duke@1: return scan(node.getExpression(), p);
duke@1: }
duke@1:
duke@1: public R visitBinary(BinaryTree node, P p) {
duke@1: R r = scan(node.getLeftOperand(), p);
duke@1: r = scanAndReduce(node.getRightOperand(), p, r);
duke@1: return r;
duke@1: }
duke@1:
duke@1: public R visitTypeCast(TypeCastTree node, P p) {
duke@1: R r = scan(node.getType(), p);
duke@1: r = scanAndReduce(node.getExpression(), p, r);
duke@1: return r;
duke@1: }
duke@1:
duke@1: public R visitInstanceOf(InstanceOfTree node, P p) {
duke@1: R r = scan(node.getExpression(), p);
duke@1: r = scanAndReduce(node.getType(), p, r);
duke@1: return r;
duke@1: }
duke@1:
duke@1: public R visitArrayAccess(ArrayAccessTree node, P p) {
duke@1: R r = scan(node.getExpression(), p);
duke@1: r = scanAndReduce(node.getIndex(), p, r);
duke@1: return r;
duke@1: }
duke@1:
duke@1: public R visitMemberSelect(MemberSelectTree node, P p) {
duke@1: return scan(node.getExpression(), p);
duke@1: }
duke@1:
mcimadamore@1143: public R visitMemberReference(MemberReferenceTree node, P p) {
mcimadamore@1143: R r = scan(node.getQualifierExpression(), p);
mcimadamore@1143: r = scanAndReduce(node.getTypeArguments(), p, r);
mcimadamore@1143: return r;
mcimadamore@1143: }
mcimadamore@1143:
duke@1: public R visitIdentifier(IdentifierTree node, P p) {
duke@1: return null;
duke@1: }
duke@1:
duke@1: public R visitLiteral(LiteralTree node, P p) {
duke@1: return null;
duke@1: }
duke@1:
duke@1: public R visitPrimitiveType(PrimitiveTypeTree node, P p) {
duke@1: return null;
duke@1: }
duke@1:
duke@1: public R visitArrayType(ArrayTypeTree node, P p) {
duke@1: return scan(node.getType(), p);
duke@1: }
duke@1:
duke@1: public R visitParameterizedType(ParameterizedTypeTree node, P p) {
duke@1: R r = scan(node.getType(), p);
duke@1: r = scanAndReduce(node.getTypeArguments(), p, r);
duke@1: return r;
duke@1: }
duke@1:
darcy@969: public R visitUnionType(UnionTypeTree node, P p) {
jjg@724: return scan(node.getTypeAlternatives(), p);
mcimadamore@550: }
mcimadamore@550:
mcimadamore@1436: public R visitIntersectionType(IntersectionTypeTree node, P p) {
mcimadamore@1436: return scan(node.getBounds(), p);
mcimadamore@1436: }
mcimadamore@1436:
duke@1: public R visitTypeParameter(TypeParameterTree node, P p) {
jjg@1521: R r = scan(node.getAnnotations(), p);
jjg@1521: r = scanAndReduce(node.getBounds(), p, r);
jjg@308: return r;
duke@1: }
duke@1:
duke@1: public R visitWildcard(WildcardTree node, P p) {
duke@1: return scan(node.getBound(), p);
duke@1: }
duke@1:
duke@1: public R visitModifiers(ModifiersTree node, P p) {
duke@1: return scan(node.getAnnotations(), p);
duke@1: }
duke@1:
duke@1: public R visitAnnotation(AnnotationTree node, P p) {
duke@1: R r = scan(node.getAnnotationType(), p);
duke@1: r = scanAndReduce(node.getArguments(), p, r);
duke@1: return r;
duke@1: }
duke@1:
jjg@1521: public R visitAnnotatedType(AnnotatedTypeTree node, P p) {
jjg@1521: R r = scan(node.getAnnotations(), p);
jjg@1521: r = scanAndReduce(node.getUnderlyingType(), p, r);
jjg@1521: return r;
jjg@1521: }
jjg@1521:
duke@1: public R visitOther(Tree node, P p) {
duke@1: return null;
duke@1: }
duke@1:
duke@1: public R visitErroneous(ErroneousTree node, P p) {
duke@1: return null;
duke@1: }
duke@1: }