read/partitioning/Distribution.java

0001 /*
0002  * Licensed to the Apache Software Foundation (ASF) under one or more
0003  * contributor license agreements.  See the NOTICE file distributed with
0004  * this work for additional information regarding copyright ownership.
0005  * The ASF licenses this file to You under the Apache License, Version 2.0
0006  * (the "License"); you may not use this file except in compliance with
0007  * the License.  You may obtain a copy of the License at
0008  *
0009  *    http://www.apache.org/licenses/LICENSE-2.0
0010  *
0011  * Unless required by applicable law or agreed to in writing, software
0012  * distributed under the License is distributed on an "AS IS" BASIS,
0013  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
0014  * See the License for the specific language governing permissions and
0015  * limitations under the License.
0016  */
0017
0018 package org.apache.spark.sql.connector.read.partitioning;
0019
0020 import org.apache.spark.annotation.Evolving;
0021 import org.apache.spark.sql.connector.read.PartitionReader;
0022
0023 /**
0024  * An interface to represent data distribution requirement, which specifies how the records should
0025  * be distributed among the data partitions (one {@link PartitionReader} outputs data for one
0026  * partition).
0027  * Note that this interface has nothing to do with the data ordering inside one
0028  * partition(the output records of a single {@link PartitionReader}).
0029  *
0030  * The instance of this interface is created and provided by Spark, then consumed by
0031  * {@link Partitioning#satisfy(Distribution)}. This means data source developers don't need to
0032  * implement this interface, but need to catch as more concrete implementations of this interface
0033  * as possible in {@link Partitioning#satisfy(Distribution)}.
0034  *
0035  * Concrete implementations until now:
0036  * <ul>
0037  *   <li>{@link ClusteredDistribution}</li>
0038  * </ul>
0039  *
0040  * @since 3.0.0
0041  */
0042 @Evolving
0043 public interface Distribution {}