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Rhino is an open-source implementation of JavaScript written entirely in Java. It is typically embedded into Java applications to provide scripting to end users.
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/* -*- Mode: java; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

package org.mozilla.javascript.ast;

import org.mozilla.javascript.Token;

/**
 * Node representing comments. Node type is {@link Token#COMMENT}.
 *
 * JavaScript effectively has five comment types:
 *
 * 

 *   // line comments
 *   
/* block comments *\/
 *   
/** jsdoc comments *\/
 *   
<!-- html-open line comments
 *   
^\\s*--> html-close line comments
 * 
 *
 * The first three should be familiar to Java programmers. JsDoc comments are really just block
 * comments with some conventions about the formatting within the comment delimiters. Line and block
 * comments are described in the Ecma-262 specification.
 *
 * 
SpiderMonkey and Rhino also support HTML comment syntax, but somewhat counterintuitively, the
 * syntax does not produce a block comment. Instead, everything from the string <!-- through the
 * end of the line is considered a comment, and if the token --> is the first non-whitespace on
 * the line, then the line is considered a line comment. This is to support parsing JavaScript in
 * <script> HTML tags that has been "hidden" from very old browsers by surrounding it with
 * HTML comment delimiters.
 *
 * Note the node start position for Comment nodes is still relative to the parent, but Comments
 * are always stored directly in the AstRoot node, so they are also effectively absolute offsets.
 */
public class Comment extends AstNode {

    private String value;
    private Token.CommentType commentType;

    {
        type = Token.COMMENT;
    }

    /**
     * Constructs a new Comment
     *
     * @param pos the start position
     * @param len the length including delimiter(s)
     * @param type the comment type
     * @param value the value of the comment, as a string
     */
    public Comment(int pos, int len, Token.CommentType type, String value) {
        super(pos, len);
        commentType = type;
        this.value = value;
    }

    /** Returns the comment style */
    public Token.CommentType getCommentType() {
        return commentType;
    }

    /**
     * Sets the comment style
     *
     * @param type the comment style, a {@link org.mozilla.javascript.Token.CommentType}
     */
    public void setCommentType(Token.CommentType type) {
        this.commentType = type;
    }

    /** Returns a string of the comment value. */
    public String getValue() {
        return value;
    }

    /**
     * Set the comment Value with the new commentString. and updates the length with new Length.
     *
     * @param commentString
     */
    public void setValue(String commentString) {
        this.value = commentString;
        this.setLength(this.value.length());
    }

    @Override
    public String toSource(int depth) {
        StringBuilder sb = new StringBuilder(getLength() + 10);
        sb.append(makeIndent(depth));
        sb.append(value);
        if (Token.CommentType.BLOCK_COMMENT == this.getCommentType()) {
            sb.append("\n");
        }
        return sb.toString();
    }

    /**
     * Comment nodes are not visited during normal visitor traversals, but comply with the {@link
     * AstNode#visit} interface.
     */
    @Override
    public void visit(NodeVisitor v) {
        v.visit(this);
    }
}