/*

  * 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 org.apache.giraph.io.formats;

 import java.io.DataOutputStream;

 import java.io.IOException;

 import org.apache.hadoop.conf.Configuration;

 import org.apache.hadoop.fs.FSDataOutputStream;

 import org.apache.hadoop.fs.FileSystem;

 import org.apache.hadoop.fs.Path;

 import org.apache.hadoop.io.Text;

 import org.apache.hadoop.io.compress.CompressionCodec;

 import org.apache.hadoop.io.compress.GzipCodec;

 import org.apache.hadoop.mapreduce.RecordWriter;

 import org.apache.hadoop.mapreduce.TaskAttemptContext;

 import org.apache.hadoop.mapreduce.lib.output.TextOutputFormat;

 import org.apache.hadoop.util.ReflectionUtils;

 /**

  * The text output format used for Giraph text writing.

  */

 public abstract class GiraphTextOutputFormat

   extends TextOutputFormat<Text, Text> {

   @Override

   public RecordWriter<Text, Text> getRecordWriter(TaskAttemptContext job)

     throws IOException, InterruptedException {

     String extension = "";

     CompressionCodec codec = null;

     Configuration conf = job.getConfiguration();

     boolean isCompressed = getCompressOutput(job);

     if (isCompressed) {

       Class<? extends CompressionCodec> codecClass =

         getOutputCompressorClass(job, GzipCodec.class);

       codec =

         (CompressionCodec) ReflectionUtils.newInstance(codecClass, conf);

       extension = codec.getDefaultExtension();

     }

     Path file = getDefaultWorkFile(job, extension);

     /* adjust the path */

     FSDataOutputStream fileOut;

     FileSystem fs = file.getFileSystem(conf);

     String subdir = getSubdir();

     if (!subdir.isEmpty()) {

       Path subdirPath = new Path(subdir);

       Path subdirAbsPath = new Path(file.getParent(), subdirPath);

       Path vertexFile = new Path(subdirAbsPath, file.getName());

       fileOut = fs.create(vertexFile, false);

     } else {

       fileOut = fs.create(file, false);

     }

     String separator = "\t";

     if (!isCompressed) {

       return new LineRecordWriter<Text, Text>(fileOut, separator);

     } else {

       DataOutputStream out =

         new DataOutputStream(codec.createOutputStream(fileOut));

       return new LineRecordWriter<Text, Text>(out, separator);

     }

   }

   /**

    * This function is used to provide an additional path level to keep

    * different text outputs into different directories.

    *

    * @return  the subdirectory to be created under the output path

    */

   protected abstract String getSubdir();

 }