sdks/java/core/src/main/java/org/apache/beam/sdk/io/ShardingFunction.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with 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,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
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 */
package org.apache.beam.sdk.io;

import java.io.Serializable;
import org.apache.beam.sdk.annotations.Experimental;
import org.apache.beam.sdk.annotations.Experimental.Kind;
import org.apache.beam.sdk.values.ShardedKey;

/** Function for assigning {@link ShardedKey}s to input elements for sharded {@link WriteFiles}. */
@Experimental(Kind.SOURCE_SINK)
public interface ShardingFunction<UserT, DestinationT> extends Serializable {

  ShardedKey<Integer> assignShardKey(DestinationT destination, UserT element, int shardCount)
      throws Exception;
}