https://openjdk.java.net/ 
/*
 * Copyright (c) 2015, 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
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package jdk.nashorn.api.tree;


A simple implementation of the TreeVisitor for ECMAScript edition 5.1.

The visit methods corresponding to ES 5.1 language constructs walk the
"components" of the given tree by calling accept method passing the
current visitor and the additional parameter.

For constructs introduced in later versions, visitUnknown is called instead which throws UnknownTreeException. 
 Methods in this class may be overridden subject to their general contract. Note that annotating methods in concrete subclasses with @Override will help ensure that methods are overridden as intended. 
Type parameters:
  • <R> – the return type of this visitor's methods. Use Void for visitors that do not need to return results.
  • <P> – the type of the additional parameter to this visitor's methods. Use Void for visitors that do not need an additional parameter.
/**
 * A simple implementation of the TreeVisitor for ECMAScript edition 5.1.
 *
 * <p>The visit methods corresponding to ES 5.1 language constructs walk the
 * "components" of the given tree by calling accept method passing the
 * current visitor and the additional parameter.
 *
 * <p>For constructs introduced in later versions, {@code visitUnknown}
 * is called instead which throws {@link UnknownTreeException}.
 *
 * <p> Methods in this class may be overridden subject to their
 * general contract.  Note that annotating methods in concrete
 * subclasses with {@link java.lang.Override @Override} will help
 * ensure that methods are overridden as intended.
 *
 * @param <R> the return type of this visitor's methods.  Use {@link
 *            Void} for visitors that do not need to return results.
 * @param <P> the type of the additional parameter to this visitor's
 *            methods.  Use {@code Void} for visitors that do not need an
 *            additional parameter.
 */
public class SimpleTreeVisitorES5_1<R, P> implements TreeVisitor<R, P> {
    @Override
    public R visitAssignment(final AssignmentTree node, final P r) {
        node.getVariable().accept(this, r);
        node.getExpression().accept(this, r);
        return null;
    }

    @Override
    public R visitCompoundAssignment(final CompoundAssignmentTree node, final P r) {
        node.getVariable().accept(this, r);
        node.getExpression().accept(this, r);
        return null;
    }

    
Visits a ModuleTree tree by calling 
visitUnknown. 
Params:
  • node –  {@inheritDoc}
  • p –  {@inheritDoc}
Returns:the result of visitUnknown
/**
     * Visits a {@code ModuleTree} tree by calling {@code
     * visitUnknown}.
     *
     * @param node  {@inheritDoc}
     * @param p  {@inheritDoc}
     * @return the result of {@code visitUnknown}
     */
    @Override
    public R visitModule(final ModuleTree node, final P p) {
        return visitUnknown(node, p);
    }

    
Visits an ExportEntryTree tree by calling 
visitUnknown. 
Params:
  • node –  {@inheritDoc}
  • p –  {@inheritDoc}
Returns:the result of visitUnknown
/**
     * Visits an {@code ExportEntryTree} tree by calling {@code
     * visitUnknown}.
     *
     * @param node  {@inheritDoc}
     * @param p  {@inheritDoc}
     * @return the result of {@code visitUnknown}
     */
    @Override
    public R visitExportEntry(final ExportEntryTree node, final P p) {
        return visitUnknown(node, p);
    }

    
Visits an ImportEntryTree tree by calling 
visitUnknown. 
Params:
  • node –  {@inheritDoc}
  • p –  {@inheritDoc}
Returns:the result of visitUnknown
/**
     * Visits an {@code ImportEntryTree} tree by calling {@code
     * visitUnknown}.
     *
     * @param node  {@inheritDoc}
     * @param p  {@inheritDoc}
     * @return the result of {@code visitUnknown}
     */
    @Override
    public R visitImportEntry(final ImportEntryTree node, final P p) {
        return visitUnknown(node, p);
    }

    @Override
    public R visitBinary(final BinaryTree node, final P r) {
        node.getLeftOperand().accept(this, r);
        node.getRightOperand().accept(this, r);
        return null;
    }

    @Override
    public R visitBlock(final BlockTree node, final P r) {
        node.getStatements().forEach((tree) -> {
            tree.accept(this, r);
        });
        return null;
    }

    @Override
    public R visitBreak(final BreakTree node, final P r) {
        return null;
    }

    @Override
    public R visitCase(final CaseTree node, final P r) {
        final Tree caseVal = node.getExpression();
        if (caseVal != null) {
            caseVal.accept(this, r);
        }

        node.getStatements().forEach((tree) -> {
            tree.accept(this, r);
        });
        return null;
    }

    @Override
    public R visitCatch(final CatchTree node, final P r) {
        final Tree cond = node.getCondition();
        if (cond != null) {
            cond.accept(this, r);
        }
        node.getParameter().accept(this, r);
        node.getBlock().accept(this, r);
        return null;
    }

    
Visits a ClassDeclarationTree tree by calling 
visitUnknown. 
Params:
  • node –  {@inheritDoc}
  • p –  {@inheritDoc}
Returns:the result of visitUnknown
/**
     * Visits a {@code ClassDeclarationTree} tree by calling {@code
     * visitUnknown}.
     *
     * @param node  {@inheritDoc}
     * @param p  {@inheritDoc}
     * @return the result of {@code visitUnknown}
     */
    @Override
    public R visitClassDeclaration(final ClassDeclarationTree node, final P p) {
        return visitUnknown(node, p);
    }

    
Visits a ClassExpressionTree tree by calling 
visitUnknown. 
Params:
  • node –  {@inheritDoc}
  • p –  {@inheritDoc}
Returns:the result of visitUnknown
/**
     * Visits a {@code ClassExpressionTree} tree by calling {@code
     * visitUnknown}.
     *
     * @param node  {@inheritDoc}
     * @param p  {@inheritDoc}
     * @return the result of {@code visitUnknown}
     */
    @Override
    public R visitClassExpression(final ClassExpressionTree node, final P p) {
        return visitUnknown(node, p);
    }

    @Override
    public R visitConditionalExpression(final ConditionalExpressionTree node, final P r) {
        node.getCondition().accept(this, r);
        node.getTrueExpression().accept(this, r);
        node.getFalseExpression().accept(this, r);
        return null;
    }

    @Override
    public R visitContinue(final ContinueTree node, final P r) {
        return null;
    }

    @Override
    public R visitDebugger(final DebuggerTree node, final P r) {
        return null;
    }

    @Override
    public R visitDoWhileLoop(final DoWhileLoopTree node, final P r) {
        node.getStatement().accept(this, r);
        node.getCondition().accept(this, r);
        return null;
    }

    @Override
    public R visitErroneous(final ErroneousTree node, final P r) {
        return null;
    }

    @Override
    public R visitExpressionStatement(final ExpressionStatementTree node, final P r) {
        node.getExpression().accept(this, r);
        return null;
    }

    @Override
    public R visitForLoop(final ForLoopTree node, final P r) {
        final Tree init = node.getInitializer();
        if (init != null) {
            init.accept(this, r);
        }

        final Tree cond = node.getCondition();
        if (cond != null) {
            cond.accept(this, r);
        }

        final Tree update = node.getUpdate();
        if (update != null) {
            update.accept(this, r);
        }

        node.getStatement().accept(this, r);
        return null;
    }

    @Override
    public R visitForInLoop(final ForInLoopTree node, final P r) {
        node.getVariable().accept(this, r);
        node.getExpression().accept(this, r);
        final StatementTree stat = node.getStatement();
        if (stat != null) {
            stat.accept(this, r);
        }
        return null;
    }

    
Visits a ForOfLoopTree tree by calling 
visitUnknown. 
Params:
  • node –  {@inheritDoc}
  • p –  {@inheritDoc}
Returns:the result of visitUnknown
/**
     * Visits a {@code ForOfLoopTree} tree by calling {@code
     * visitUnknown}.
     *
     * @param node  {@inheritDoc}
     * @param p  {@inheritDoc}
     * @return the result of {@code visitUnknown}
     */
    @Override
    public R visitForOfLoop(final ForOfLoopTree node, final P p) {
        return visitUnknown(node, p);
    }

    @Override
    public R visitFunctionCall(final FunctionCallTree node, final P r) {
        node.getFunctionSelect().accept(this, r);
        node.getArguments().forEach((tree) -> {
            tree.accept(this, r);
        });
        return null;
    }

    @Override
    public R visitFunctionDeclaration(final FunctionDeclarationTree node, final P r) {
        node.getParameters().forEach((tree) -> {
            tree.accept(this, r);
        });
        node.getBody().accept(this, r);
        return null;
    }

    @Override
    public R visitFunctionExpression(final FunctionExpressionTree node, final P r) {
        node.getParameters().forEach((tree) -> {
            tree.accept(this, r);
        });
        node.getBody().accept(this, r);
        return null;
    }

    @Override
    public R visitIdentifier(final IdentifierTree node, final P r) {
        return null;
    }

    @Override
    public R visitIf(final IfTree node, final P r) {
        node.getCondition().accept(this, r);
        node.getThenStatement().accept(this, r);
        final Tree elseStat = node.getElseStatement();
        if (elseStat != null) {
            elseStat.accept(this, r);
        }
        return null;
    }

    @Override
    public R visitArrayAccess(final ArrayAccessTree node, final P r) {
        node.getExpression().accept(this, r);
        node.getIndex().accept(this, r);
        return null;
    }

    @Override
    public R visitArrayLiteral(final ArrayLiteralTree node, final P r) {
        node.getElements().stream().filter((tree) -> (tree != null)).forEach((tree) -> {
            tree.accept(this, r);
        });
        return null;
    }

    @Override
    public R visitLabeledStatement(final LabeledStatementTree node, final P r) {
        node.getStatement().accept(this, r);
        return null;
    }

    @Override
    public R visitLiteral(final LiteralTree node, final P r) {
        return null;
    }

    @Override
    public R visitParenthesized(final ParenthesizedTree node, final P r) {
        node.getExpression().accept(this, r);
        return null;
    }

    @Override
    public R visitReturn(final ReturnTree node, final P r) {
        final Tree retExpr = node.getExpression();
        if (retExpr != null) {
            retExpr.accept(this, r);
        }
        return null;
    }

    @Override
    public R visitMemberSelect(final MemberSelectTree node, final P r) {
        node.getExpression().accept(this, r);
        return null;
    }

    @Override
    public R visitNew(final NewTree node, final P r) {
        node.getConstructorExpression().accept(this, r);
        return null;
    }

    @Override
    public R visitObjectLiteral(final ObjectLiteralTree node, final P r) {
        node.getProperties().forEach((tree) -> {
            tree.accept(this, r);
        });
        return null;
    }

    @Override
    public R visitProperty(final PropertyTree node, final P r) {
        final FunctionExpressionTree getter = node.getGetter();
        if (getter != null) {
            getter.accept(this, r);
        }
        final ExpressionTree key = node.getKey();
        if (key != null) {
            key.accept(this, r);
        }

        final FunctionExpressionTree setter = node.getSetter();
        if (setter != null) {
            setter.accept(this, r);
        }

        final ExpressionTree value = node.getValue();
        if (value != null) {
            value.accept(this, r);
        }
        return null;
    }

    @Override
    public R visitRegExpLiteral(final RegExpLiteralTree node, final P r) {
        return null;
    }

    
Visits a TemplateLiteralTree tree by calling 
visitUnknown. 
Params:
  • node –  {@inheritDoc}
  • p –  {@inheritDoc}
Returns:the result of visitUnknown
/**
     * Visits a {@code TemplateLiteralTree} tree by calling {@code
     * visitUnknown}.
     *
     * @param node  {@inheritDoc}
     * @param p  {@inheritDoc}
     * @return the result of {@code visitUnknown}
     */
    @Override
    public R visitTemplateLiteral(final TemplateLiteralTree node, final P p) {
        return visitUnknown(node, p);
    }

    @Override
    public R visitEmptyStatement(final EmptyStatementTree node, final P r) {
        return null;
    }

    
Visits a SpreadTree tree by calling 
visitUnknown. 
Params:
  • node –  {@inheritDoc}
  • p –  {@inheritDoc}
Returns:the result of visitUnknown
/**
     * Visits a {@code SpreadTree} tree by calling {@code
     * visitUnknown}.
     *
     * @param node  {@inheritDoc}
     * @param p  {@inheritDoc}
     * @return the result of {@code visitUnknown}
     */
    @Override
    public R visitSpread(final SpreadTree node, final P p) {
        return visitUnknown(node, p);
    }

    @Override
    public R visitSwitch(final SwitchTree node, final P r) {
        node.getExpression().accept(this, r);
        node.getCases().forEach((tree) -> {
            tree.accept(this, r);
        });
        return null;
    }

    @Override
    public R visitThrow(final ThrowTree node, final P r) {
        node.getExpression().accept(this, r);
        return null;
    }

    @Override
    public R visitCompilationUnit(final CompilationUnitTree node, final P r) {
        node.getSourceElements().forEach((tree) -> {
            tree.accept(this, r);
        });
        return null;
    }

    @Override
    public R visitTry(final TryTree node, final P r) {
        node.getBlock().accept(this, r);
        node.getCatches().forEach((tree) -> {
            tree.accept(this, r);
        });

        final Tree finallyBlock = node.getFinallyBlock();
        if (finallyBlock != null) {
            finallyBlock.accept(this, r);
        }
        return null;
    }

    @Override
    public R visitInstanceOf(final InstanceOfTree node, final P r) {
        node.getType().accept(this, r);
        node.getExpression().accept(this, r);
        return null;
    }

    @Override
    public R visitUnary(final UnaryTree node, final P r) {
        node.getExpression().accept(this, r);
        return null;
    }

    @Override
    public R visitVariable(final VariableTree node, final P r) {
        if (node.getInitializer() != null) {
            node.getInitializer().accept(this, r);
        }
        return null;
    }

    @Override
    public R visitWhileLoop(final WhileLoopTree node, final P r) {
        node.getCondition().accept(this, r);
        node.getStatement().accept(this, r);
        return null;
    }

    @Override
    public R visitWith(final WithTree node, final P r) {
        node.getScope().accept(this, r);
        node.getStatement().accept(this, r);
        return null;
    }

    
Visits a YieldTree tree by calling 
visitUnknown. 
Params:
  • node –  {@inheritDoc}
  • p –  {@inheritDoc}
Returns:the result of visitUnknown
/**
     * Visits a {@code YieldTree} tree by calling {@code
     * visitUnknown}.
     *
     * @param node  {@inheritDoc}
     * @param p  {@inheritDoc}
     * @return the result of {@code visitUnknown}
     */
    @Override
    public R visitYield(final YieldTree node, final P p) {
        return visitUnknown(node, p);
    }

    
{@inheritDoc}

Params:
  • node –  {@inheritDoc}
  • p –  {@inheritDoc}
Throws:
Implementation Requirements:The default implementation of this method in 
SimpleTreeVisitorES5_1 will always throw 
UnknownTypeException. This behavior is not required of a subclass.
Returns:abnormal return by throwing exception always
/**
     * {@inheritDoc}
     *
     * @implSpec The default implementation of this method in {@code
     * SimpleTreeVisitorES5_1} will always throw {@code
     * UnknownTypeException}. This behavior is not required of a
     * subclass.
     *
     * @param node  {@inheritDoc}
     * @param p  {@inheritDoc}
     * @return abnormal return by throwing exception always
     * @throws UnknownTreeException
     *  a visitor implementation may optionally throw this exception
     */
    @Override
    public R visitUnknown(final Tree node, final P p) {
        // unknown in ECMAScript 5.1 edition
        throw new UnknownTreeException(node, p);
    }
}