/*
* 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 limitations
* under the License.
*/
package com.aliyun.odps.graph;
import java.io.IOException;
import com.aliyun.odps.conf.Configuration;
/**
* Aggregator的分区类，决定某个{@link Aggregator}的owner定位到哪个Worker
*
* 可以通过{@link GraphJob#setAggregatorOwnerPartitionerClass(Class)}方法自定义分区类，否则使用默认的分区类
* HashPartitioner
*/
@SuppressWarnings({"rawtypes"})
public abstract class AggregatorOwnerPartitioner {
/**
* 此方法会在分区类对象被new出来后立即调用，传入运行时的{@link JobConf}对象
*
* @param conf
* 运行时的JobConf对象
*/
public void configure(Configuration conf) throws IOException {
}
/**
* 给定 AggregatorId 和 Worker 个数，决定该aggregator的owner定位到哪个Worker.
* <p>
* 此方法通常实现为对AggregatorId的某个哈希函数，默认的分区类 HashAggregatorOwnerPartitioner
* </p>
*
* @param aggregatorId
* Aggregator序号，该值对应该Aggregator在Aggregator列表中从0开始的序号.
* 例如第一个aggregator对应的aggregatorId为0,第n个aggregator对应aggregatorId为n-1.
* @param workerNum
* 分区数，既 Worker 个数
* @return 分区序号，必须是 0 到 numWorkers-1
*/
public abstract int getOwner(int aggregatorId, int workerNum);
}