Identity.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 limitations
 * under the License.
 */

package com.aliyun.odps.mapred.example;

import java.io.IOException;
import java.util.Iterator;

import com.aliyun.odps.Column;
import com.aliyun.odps.OdpsException;
import com.aliyun.odps.OdpsType;
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.ReducerBase;
import com.aliyun.odps.mapred.conf.JobConf;
import com.aliyun.odps.mapred.utils.InputUtils;
import com.aliyun.odps.mapred.utils.OutputUtils;

public class Identity {

  public static class IdentityMapper extends MapperBase {

    Record v;

    @Override
    public void setup(TaskContext context) throws IOException {
      v = context.createMapOutputValueRecord();
    }

    @Override
    public void map(long recordNum, Record record, TaskContext context)
        throws IOException {
      context.write(record, v);
    }
  }

  public static class IdentityReducer extends ReducerBase {

    @Override
    public void reduce(Record key, Iterator<Record> values, TaskContext context)
        throws IOException {
      context.write(key);
    }
  }

  public static void main(String[] args) throws OdpsException {
    if (args.length != 2) {
      System.err.println("Usage: Identity <in_table> <out_table>");
      System.exit(2);
    }

    JobConf job = new JobConf();
    job.setMapperClass(IdentityMapper.class);
    job.setReducerClass(IdentityReducer.class);
    job.setMapOutputKeySchema(new Column[]{new Column("word", OdpsType.STRING)});
    job.setMapOutputValueSchema(new Column[]{new Column("count",
                                                        OdpsType.BIGINT)});

    InputUtils.addTable(TableInfo.builder().tableName(args[0]).build(), job);
    OutputUtils.addTable(TableInfo.builder().tableName(args[1]).build(), job);

    JobClient.runJob(job);
  }
}