/*
 * $Id$
 *
 * Copyright (c) 2001, 2020, 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 com.sun.tck.lib.tgf;

class UniteIterator extends NodeIterator {

    private ValuesIterator currentIterator;

    public void setLeft(ValuesIterator left) {
        super.setLeft(left);
        currentIterator = left;
    }

    public void shift() {
        currentIterator.shift();
    }

    public boolean hasNext() {
        if (currentIterator.hasNext()) {
            return true;
        }
        else if (currentIterator == getLeft()) {
            currentIterator = getRight();
            return currentIterator.hasNext();
        }
        else {
            return false;
        }
    }

    protected void rollback() {
        super.rollback();
        currentIterator = getLeft();
        switchToRightIfNeeded();
    }

    private void switchToRightIfNeeded() {
        if ( currentIterator == getLeft() && !currentIterator.hasNext() ) {
            currentIterator = getRight();
        }
    }

    public Object[] next() {
        switchToRightIfNeeded();
        Object[] result = currentIterator.next();
        if (root) {
            shift();
        }
        return result;
    }


}
