/** * Write out a SequenceFile that can be read by TotalOrderPartitioner that contains the split * points in startKeys. * * <p>This method was copied from HFileOutputFormat in hbase-0.90.1-cdh3u0. I had to copy it * because it's private. * * @param conf The job configuration. * @param partitionsPath output path for SequenceFile. * @param startKeys the region start keys to use as the partitions. * @throws IOException If there is an error. */ private static void writePartitionFile( Configuration conf, Path partitionsPath, List<HFileKeyValue> startKeys) throws IOException { if (startKeys.isEmpty()) { throw new IllegalArgumentException("No regions passed"); } // We're generating a list of split points, and we don't ever // have keys < the first region (which has an empty start key) // so we need to remove it. Otherwise we would end up with an // empty reducer with index 0. TreeSet<HFileKeyValue> sorted = new TreeSet<HFileKeyValue>(); sorted.addAll(startKeys); HFileKeyValue first = sorted.first(); if (0 != first.getRowKey().length) { throw new IllegalArgumentException( "First region of table should have empty start row key. Instead has: " + Bytes.toStringBinary(first.getRowKey())); } sorted.remove(first); // Write the actual file final SequenceFile.Writer writer = KijiMRPlatformBridge.get() .newSeqFileWriter(conf, partitionsPath, HFileKeyValue.class, NullWritable.class); try { for (HFileKeyValue startKey : sorted) { writer.append(startKey, NullWritable.get()); } } finally { writer.close(); } }