org.apache.giraph.io.formats.GiraphTextOutputFormat.java Source code

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Here is the source code for org.apache.giraph.io.formats.GiraphTextOutputFormat.java

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/*
 * 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();
}