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Concourse is a self-tuning database that is designed for both ad hoc analytics and high volume transactions at scale. Developers use Concourse to quickly build mission critical software while also benefiting from real time insight into their most important data. With Concourse, end-to-end data management requires no extra infrastructure, no prior configuration and no additional coding–all of which greatly reduce costs and allow developers to focus on core business problems.

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/*
 * Copyright (c) 2013-2019 Cinchapi Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.cinchapi.concourse.lang.sort;

import java.util.List;

/**
 * {@link Order} encapsulates the semantics of a result set sorting. Any given
 * time, objects of this class can exist in one of two modes: {@code building}
 * or {@code built}. When an Order is
 * {@code built}, it is guaranteed to represent a fully and well formed sort
 * order that can be processed. On the other hand, when a Order is
 * {@code building} it is in an incomplete state.
 * 
 * This class is the public interface to Order construction. It is meant to
 * be used in a chained manner, where the caller initially calls
 * {@link Order#by} and continues to construct the Order using the
 * options available from each subsequently returned state.
 * 
 */
public interface Order {

    /**
     * Return an {@link Order} that specifies no order.
     * 
     * @return a no-op {@link Order}
     */
    public static Order none() {
        return NoOrder.INSTANCE;
    }

    /**
     * Start building a new {@link Order}.
     *
     * @return the Order builder
     */
    public static OrderByState by(String key) {
        BuiltOrder order = new BuiltOrder();
        return new OrderByState(order, key, Direction.$default());
    }

    /**
     * Return the order specification, expressed as an ordered list of
     * {@link OrderComponent components} containing each key, an optional
     * {@link Timestamp} and the the corresponding direction ordinal (e.g. 1 for
     * ASC and -1 for DESC) in the constructed {@link Order}.
     */
    public List spec();

}