/*-
 *
 *  This file is part of Oracle NoSQL Database
 *  Copyright (C) 2011, 2014 Oracle and/or its affiliates.  All rights reserved.
 *
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 *
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 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Affero General Public License for more details.
 *
 *  You should have received a copy of the GNU Affero General Public
 *  License in the LICENSE file along with Oracle NoSQL Database.  If not,
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 *
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 *  supercedes this license.
 *
 *  For more information please contact:
 *
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 *  Oracle America, Inc.
 *  5OP-10
 *  500 Oracle Parkway
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 *
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 *
 *  berkeleydb-info_us@oracle.com
 *
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 *  EOF
 *
 */

package oracle.kv;

import java.util.EnumSet;

/**
 * Used with iterator operations to specify the order that keys are returned.
 */
public enum Direction {

    /**
     * Iterate in ascending key order.
     */
    FORWARD,

    /**
     * Iterate in descending key order.
     */
    REVERSE,

    /**
     * Iterate in no particular key order.
     */
    UNORDERED;

    private final static Direction[] DIRECTIONS_BY_ORDINAL;
    static {
        final EnumSet<Direction> set = EnumSet.allOf(Direction.class);
        DIRECTIONS_BY_ORDINAL = new Direction[set.size()];
        for (Direction op : set) {
            DIRECTIONS_BY_ORDINAL[op.ordinal()] = op;
        }
    }

    /**
     * For internal use only.
     * @hidden
     */
    public static Direction getDirection(int ordinal) {
        if (ordinal < 0 || ordinal >= DIRECTIONS_BY_ORDINAL.length) {
            throw new RuntimeException("unknown Direction: " + ordinal);
        }
        return DIRECTIONS_BY_ORDINAL[ordinal];
    }
}
