Java example source code file (LabelNode.java)

This example Java source code file (LabelNode.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

block, identnode, immutable, labelnode, lexicalcontext, lexicalcontextstatement, nodevisitor, override, stringbuilder

The LabelNode.java Java example source code

/*
 * Copyright (c) 2010, 2013, 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
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package jdk.nashorn.internal.ir;

import jdk.nashorn.internal.ir.annotations.Immutable;
import jdk.nashorn.internal.ir.visitor.NodeVisitor;

/**
 * IR representation for a labeled statement.
 */
@Immutable
public final class LabelNode extends LexicalContextStatement {
    /** Label ident. */
    private final IdentNode label;

    /** Statements. */
    private final Block body;

    /**
     * Constructor
     *
     * @param lineNumber line number
     * @param token      token
     * @param finish     finish
     * @param label      label identifier
     * @param body       body of label node
     */
    public LabelNode(final int lineNumber, final long token, final int finish, final IdentNode label, final Block body) {
        super(lineNumber, token, finish);

        this.label = label;
        this.body  = body;
    }

    private LabelNode(final LabelNode labelNode, final IdentNode label, final Block body) {
        super(labelNode);
        this.label = label;
        this.body  = body;
    }

    @Override
    public boolean isTerminal() {
        return body.isTerminal();
    }

    @Override
    public Node accept(final LexicalContext lc, final NodeVisitor<? extends LexicalContext> visitor) {
        if (visitor.enterLabelNode(this)) {
            return visitor.leaveLabelNode(
                setLabel(lc, (IdentNode)label.accept(visitor)).
                setBody(lc, (Block)body.accept(visitor)));
        }

        return this;
    }

    @Override
    public void toString(final StringBuilder sb) {
        label.toString(sb);
        sb.append(':');
    }

    /**
     * Get the body of the node
     * @return the body
     */
    public Block getBody() {
        return body;
    }

    /**
     * Reset the body of the node
     * @param lc lexical context
     * @param body new body
     * @return new for node if changed or existing if not
     */
    public LabelNode setBody(final LexicalContext lc, final Block body) {
        if (this.body == body) {
            return this;
        }
        return Node.replaceInLexicalContext(lc, this, new LabelNode(this, label, body));
    }

    /**
     * Get the identifier representing the label name
     * @return the label
     */
    public IdentNode getLabel() {
        return label;
    }

    private LabelNode setLabel(final LexicalContext lc, final IdentNode label) {
        if (this.label == label) {
            return this;
        }
        return Node.replaceInLexicalContext(lc, this, new LabelNode(this, label, body));
    }

}