com.metamx.druid.indexer.Utils.java Source code

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Here is the source code for com.metamx.druid.indexer.Utils.java

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/*
 * Druid - a distributed column store.
 * Copyright (C) 2012  Metamarkets Group Inc.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

package com.metamx.druid.indexer;

import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.google.common.base.Preconditions;
import com.google.common.collect.Iterators;
import com.metamx.common.ISE;
import com.metamx.druid.jackson.DefaultObjectMapper;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.compress.CompressionCodec;
import org.apache.hadoop.io.compress.GzipCodec;
import org.apache.hadoop.mapreduce.JobContext;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.util.ReflectionUtils;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

/**
 */
public class Utils {
    private static final ObjectMapper jsonMapper = new DefaultObjectMapper();

    public static <K, V> Map<K, V> zipMap(Iterable<K> keys, Iterable<V> values) {
        Map<K, V> retVal = new HashMap<K, V>();

        Iterator<K> keyIter = keys.iterator();
        Iterator<V> valsIter = values.iterator();
        while (keyIter.hasNext()) {
            final K key = keyIter.next();

            Preconditions.checkArgument(valsIter.hasNext(),
                    "keys longer than vals, bad, bad vals.  Broke on key[%s]", key);
            retVal.put(key, valsIter.next());
        }
        if (valsIter.hasNext()) {
            throw new ISE("More values[%d] than keys[%d]", retVal.size() + Iterators.size(valsIter), retVal.size());
        }

        return retVal;
    }

    public static OutputStream makePathAndOutputStream(JobContext job, Path outputPath, boolean deleteExisting)
            throws IOException {
        OutputStream retVal;
        FileSystem fs = outputPath.getFileSystem(job.getConfiguration());

        if (fs.exists(outputPath)) {
            if (deleteExisting) {
                fs.delete(outputPath, false);
            } else {
                throw new ISE("outputPath[%s] must not exist.", outputPath);
            }
        }

        if (!FileOutputFormat.getCompressOutput(job)) {
            retVal = fs.create(outputPath, false);
        } else {
            Class<? extends CompressionCodec> codecClass = FileOutputFormat.getOutputCompressorClass(job,
                    GzipCodec.class);
            CompressionCodec codec = ReflectionUtils.newInstance(codecClass, job.getConfiguration());
            outputPath = new Path(outputPath.toString() + codec.getDefaultExtension());

            retVal = codec.createOutputStream(fs.create(outputPath, false));
        }

        return retVal;
    }

    public static InputStream openInputStream(JobContext job, Path inputPath) throws IOException {
        return openInputStream(inputPath, inputPath.getFileSystem(job.getConfiguration()));
    }

    public static InputStream openInputStream(Path inputPath, final FileSystem fileSystem) throws IOException {
        return fileSystem.open(inputPath);
    }

    public static Map<String, Object> getStats(JobContext job, Path statsPath) throws IOException {
        FileSystem fs = statsPath.getFileSystem(job.getConfiguration());

        return jsonMapper.readValue(fs.open(statsPath), new TypeReference<Map<String, Object>>() {
        });
    }

    public static void storeStats(JobContext job, Path path, Map<String, Object> stats) throws IOException {
        jsonMapper.writeValue(makePathAndOutputStream(job, path, true), stats);
    }
}