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 * Copyright (c)  2017, 2018, 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 jdk.incubator.sql2;

/**

 * Interface used to indicate that this object represents a Sharding Key. A

 * {@link ShardingKey} instance is only guaranteed to be compatible with the

 * data source instance that it was derived from. A {@link ShardingKey} is

 * created using {@link Builder}.

 * <p>

 * The following example illustrates the use of {@link Builder} to create a

 * {@link ShardingKey}:

 * <pre>

 * {@code

 *

 *     DataSource ds = new MyDataSource();

 *     ShardingKey shardingKey = ds.createShardingKeyBuilder()

 *                           .subkey("abc", JDBCType.VARCHAR)

 *                           .subkey(94002, JDBCType.INTEGER)

 *                           .build();

 * }

 * </pre>

 * <p>

 *

 * A {@link ShardingKey} is used for specifying a

 * composite Sharding may use a * to specify a additional level of partitioning

 * within to specify a additional level of partitioning within the Shard.

 * <p>

 * The following example illustrates the use of {@link Builder} to create a

 * branch office:

 * <pre>

 * {@code

 *

 *     DataSource ds = new MyDataSource();

 *     ShardingKey superShardingKey = ds.shardingKeyBuilder()

 *                           .subkey("EASTERN_REGION", JDBCType.VARCHAR)

 *                           .build();

 *     ShardingKey shardingKey = ds.shardingKeyBuilder()

 *                           .subkey("PITTSBURGH_BRANCH", JDBCType.VARCHAR)

 *                           .build();

 *                           .property(SHARDING_GROUP_KEY, superShardingKey)

 *                           .property(SHARDING_KEY, shardingKey)

 *                           .build();

 * }

 * </pre>

 */

public interface ShardingKey {

  /**

   * A builder created from a {@link DataSource} or object, used to create a

   * {@link ShardingKey} with sub-keys of supported data types. Implementations

   * must support JDBCType.VARCHAR and may also support additional data types.

   * <p>

   * The following example illustrates the use of {@link Builder} to create a

   * {@link ShardingKey}:

   * <pre>

   * {@code

   *

   *     DataSource ds = new MyDataSource();

   *     ShardingKey shardingKey = ds.createShardingKeyBuilder()

   *                           .subkey("abc", JDBCType.VARCHAR)

   *                           .subkey(94002, JDBCType.INTEGER)

   *                           .build();

   * }

   * </pre>

   */

  public interface Builder {

    /**

     * This method will be called to add a subkey into a Sharding Key object

     * being built. The order in which subkey method is called is important as

     * it indicates the order of placement of the subkey within the Sharding

     * Key.

     *

     * @param subkey contains the object that needs to be part of shard sub key

     * @param subkeyType sub-key data type of type java.sql.SQLType

     * @return this builder object

     */

    public Builder subkey(Object subkey, SqlType subkeyType);

    /**

     * Returns an instance of the object defined by this builder.

     *

     * @return The built object

     */

    public ShardingKey build();

  }

}