org.apache.spark.sql.sources.v2.reader.partitioning.Distribution Maven / Gradle / Ivy
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* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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,
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package org.apache.spark.sql.sources.v2.reader.partitioning;
import org.apache.spark.annotation.InterfaceStability;
import org.apache.spark.sql.sources.v2.reader.DataReader;
/**
* An interface to represent data distribution requirement, which specifies how the records should
* be distributed among the data partitions(one {@link DataReader} outputs data for one partition).
* Note that this interface has nothing to do with the data ordering inside one
* partition(the output records of a single {@link DataReader}).
*
* The instance of this interface is created and provided by Spark, then consumed by
* {@link Partitioning#satisfy(Distribution)}. This means data source developers don't need to
* implement this interface, but need to catch as more concrete implementations of this interface
* as possible in {@link Partitioning#satisfy(Distribution)}.
*
* Concrete implementations until now:
*
* - {@link ClusteredDistribution}
*
*/
@InterfaceStability.Evolving
public interface Distribution {}