content: /*
   * 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.mapred.open.example;
  
  import java.io.IOException;
  import java.util.Iterator;
  
  import com.aliyun.odps.data.Record;
  import com.aliyun.odps.data.TableInfo;
  import com.aliyun.odps.mapred.JobClient;
  import com.aliyun.odps.mapred.MapperBase;
  import com.aliyun.odps.mapred.RunningJob;
  import com.aliyun.odps.mapred.TaskContext;
  import com.aliyun.odps.mapred.conf.JobConf;
  import com.aliyun.odps.mapred.utils.InputUtils;
  import com.aliyun.odps.mapred.utils.OutputUtils;
  import com.aliyun.odps.mapred.utils.SchemaUtils;
  
  /**
   * MultiJobs
   * 
   * Running multiple job
   * 
   **/
  public class MultiJobs {
  
    public static class InitMapper extends MapperBase {
  
      @Override
      public void setup(TaskContext context) throws IOException {
        Record record = context.createOutputRecord();
        long v = context.getJobConf().getLong("multijobs.value", 2);
        record.set(0, v);
        context.write(record);
      }
    }
  
    public static class DecreaseMapper extends MapperBase {
  
      @Override
      public void cleanup(TaskContext context) throws IOException {
        // 从JobConf中获取main函数中定义的变量值
        long expect = context.getJobConf().getLong("multijobs.expect.value", -1);
        long v = -1;
        int count = 0;
  
        // 读取资源表里面的数据，这个表是上一个job的输出表
        Iterator<Record> iter = context.readResourceTable("multijobs_res_table");
        while (iter.hasNext()) {
          Record r = iter.next();
          v = (Long) r.get(0);
          if (expect != v) {
            throw new IOException("expect: " + expect + ", but: " + v);
          }
          count++;
        }
  
        if (count != 1) {
          throw new IOException("res_table should have 1 record, but: " + count);
        }
  
        Record record = context.createOutputRecord();
        v--;
        record.set(0, v);
        context.write(record);
        // 设置counter，counter在作业成功结束后，可以在main函数中获取到
        context.getCounter("multijobs", "value").setValue(v);
      }
    }
  
    public static void main(String[] args) throws Exception {
      if (args.length != 1) {
        System.err.println("Usage: TestMultiJobs <table>");
        System.exit(1);
      }
      String tbl = args[0];
      long iterCount = 2;
  
      System.err.println("Start to run init job.");
  
      JobConf initJob = new JobConf();
  
      initJob.setLong("multijobs.value", iterCount);
      initJob.setMapperClass(InitMapper.class);
  
      InputUtils.addTable(TableInfo.builder().tableName("mr_empty").build(), initJob);
      OutputUtils.addTable(TableInfo.builder().tableName(tbl).build(), initJob);
  
      initJob.setMapOutputKeySchema(SchemaUtils.fromString("key:string"));
      initJob.setMapOutputValueSchema(SchemaUtils.fromString("value:string"));
  
      // maponly作业需要显式设置reducer的数目为0
      initJob.setNumReduceTasks(0);
  
      JobClient.runJob(initJob);
  
      while (true) {
        System.err.println("Start to run iter job, count: " + iterCount);
  
        JobConf decJob = new JobConf();
  
        decJob.setLong("multijobs.expect.value", iterCount);
        decJob.setMapperClass(DecreaseMapper.class);
  
        InputUtils.addTable(TableInfo.builder().tableName("mr_empty").build(), decJob);
        OutputUtils.addTable(TableInfo.builder().tableName(tbl).build(), decJob);
  
        // maponly作业需要显式设置reducer的数目为0
        decJob.setNumReduceTasks(0);
  
        RunningJob rJob = JobClient.runJob(decJob);
  
        iterCount--;
  
        // 如果迭代次数已经达到，则退出循环
        if (rJob.getCounters().findCounter("multijobs", "value").getValue() == 0) {
          break;
        }
      }
  
      if (iterCount != 0) {
        throw new IOException("Job failed.");
      }
    }
  }
  