org.eclipse.jdt.core.dom.Comment.java Source code

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Here is the source code for org.eclipse.jdt.core.dom.Comment.java

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/*******************************************************************************
 * Copyright (c) 2004, 2019 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.jdt.core.dom;

/**
 * Abstract base class for all AST nodes that represent comments.
 * There are exactly three kinds of comment:
 * line comments ({@link LineComment}),
 * block comments ({@link BlockComment}), and
 * doc comments ({@link Javadoc}).
 * <pre>
 * Comment:
 *     LineComment
 *     BlockComment
 *     Javadoc
 * </pre>
 *
 * @since 3.0
 */
public abstract class Comment extends ASTNode {

    /**
     * Alternate root node, or <code>null</code> if none.
     * Initially <code>null</code>.
     */
    private ASTNode alternateRoot = null;

    /**
     * Creates a new AST node for a comment owned by the given AST.
     * <p>
     * N.B. This constructor is package-private.
     * </p>
     *
     * @param ast the AST that is to own this node
     */
    Comment(AST ast) {
        super(ast);
    }

    /**
     * Returns whether this comment is a block comment
     * (<code>BlockComment</code>).
     *
     * @return <code>true</code> if this is a block comment, and
     *    <code>false</code> otherwise
     */
    public final boolean isBlockComment() {
        return (this instanceof BlockComment);
    }

    /**
     * Returns whether this comment is a line comment
     * (<code>LineComment</code>).
     *
     * @return <code>true</code> if this is a line comment, and
     *    <code>false</code> otherwise
     */
    public final boolean isLineComment() {
        return (this instanceof LineComment);
    }

    /**
     * Returns whether this comment is a doc comment
     * (<code>Javadoc</code>).
     *
     * @return <code>true</code> if this is a doc comment, and
     *    <code>false</code> otherwise
     */
    public final boolean isDocComment() {
        return (this instanceof Javadoc);
    }

    /**
     * Returns the root AST node that this comment occurs
     * within, or <code>null</code> if none (or not recorded).
     * <p>
     * Typically, the comment nodes created while parsing a compilation
     * unit are not considered descendents of the normal AST
     * root, namely an {@link CompilationUnit}. Instead, these
     * comment nodes exist outside the normal AST and each is
     * a root in its own right. This optional property provides
     * a well-known way to navigate from the comment to the
     * compilation unit in such cases. Note that the alternate root
     * property is not one of the comment node's children. It is simply a
     * reference to a node.
     * </p>
     *
     * @return the alternate root node, or <code>null</code>
     * if none
     * @see #setAlternateRoot(ASTNode)
     */
    public final ASTNode getAlternateRoot() {
        return this.alternateRoot;
    }

    /**
     * Returns the root AST node that this comment occurs
     * within, or <code>null</code> if none (or not recorded).
     *
     * @param root the alternate root node, or <code>null</code>
     * if none
     * @see #getAlternateRoot()
     */
    public final void setAlternateRoot(ASTNode root) {
        // alternate root is *not* considered a structural property
        // but we protect them nevertheless
        checkModifiable();
        this.alternateRoot = root;
    }

    @Override
    int memSize() {
        return BASE_NODE_SIZE + 1 * 4;
    }
}