src/share/classes/com/sun/source/util/TreeScanner.java - toolchain/jdk/jdk9_langtools - Git at Google

 /*
  * Copyright 2005-2006 Sun Microsystems, Inc.  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.  Sun designates this
  * particular file as subject to the "Classpath" exception as provided
  * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  * CA 95054 USA or visit www.sun.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 Ah&eacute;
  * @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.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 visitTypeParameter(TypeParameterTree node, P p) {
         return scan(node.getBounds(), p);
     }

     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 visitOther(Tree node, P p) {
         return null;
     }

     public R visitErroneous(ErroneousTree node, P p) {
         return null;
     }
 }
	/*
	* Copyright 2005-2006 Sun Microsystems, Inc. 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. Sun designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
	* CA 95054 USA or visit www.sun.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.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 visitTypeParameter(TypeParameterTree node, P p) {
	return scan(node.getBounds(), p);
	}

	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 visitOther(Tree node, P p) {
	return null;
	}

	public R visitErroneous(ErroneousTree node, P p) {
	return null;
	}
	}