/*
 * $Id$
 *
 * 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
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 */

package com.sun.tck.lib.tgf;

import java.util.Arrays;


class IntersectIterator extends NodeIterator {

    private static final Object[][] EMPTY_2DIM_ARRAY = new Object[0][0];
    private Object[] result;

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

    public boolean hasNext() {
        while (getLeft().hasNext()) {
            Object[] leftNext = getLeft().next();
            // hard rollback
            setRight( getRight().createCopy() );
            while (getRight().hasNext()) {
                Object[] rightNext = getRight().next();
                getRight().shift();
                if (Arrays.deepEquals(leftNext, rightNext)) {
                    result = leftNext;
                    return true;
                }
            }
            getLeft().shift();
        }
        result = EMPTY_2DIM_ARRAY;
        return false;
    }

    protected void rollback() {
        setLeft(getLeft().createCopy());
        hasNext();
    }

    public Object[] next() {
        if (result == null) hasNext();
        if (root) {
            shift();
        }
        return result;
    }


}
