private void createBAM(final List<GATKSAMRecord> reads) throws IOException {
    testBAM = File.createTempFile("TraverseActiveRegionsUnitTest", ".bam");
    testBAM.deleteOnExit();

    SAMFileWriter out =
        new SAMFileWriterFactory()
            .setCreateIndex(true)
            .makeBAMWriter(reads.get(0).getHeader(), true, testBAM);
    for (GATKSAMRecord read : reads) {
      out.addAlignment(read);
    }
    out.close();

    new File(testBAM.getAbsolutePath().replace(".bam", ".bai")).deleteOnExit();
    new File(testBAM.getAbsolutePath() + ".bai").deleteOnExit();
  }
  protected int doWork() {
    IoUtil.assertFileIsReadable(INPUT);
    IoUtil.assertFileIsWritable(OUTPUT);

    final SAMFileReader in = new SAMFileReader(INPUT);

    // create the read group we'll be using
    final SAMReadGroupRecord rg = new SAMReadGroupRecord(RGID);
    rg.setLibrary(RGLB);
    rg.setPlatform(RGPL);
    rg.setSample(RGSM);
    rg.setPlatformUnit(RGPU);
    if (RGCN != null) rg.setSequencingCenter(RGCN);
    if (RGDS != null) rg.setDescription(RGDS);
    if (RGDT != null) rg.setRunDate(RGDT);

    log.info(
        String.format(
            "Created read group ID=%s PL=%s LB=%s SM=%s%n",
            rg.getId(), rg.getPlatform(), rg.getLibrary(), rg.getSample()));

    // create the new header and output file
    final SAMFileHeader inHeader = in.getFileHeader();
    final SAMFileHeader outHeader = inHeader.clone();
    outHeader.setReadGroups(Arrays.asList(rg));
    if (SORT_ORDER != null) outHeader.setSortOrder(SORT_ORDER);

    final SAMFileWriter outWriter =
        new SAMFileWriterFactory()
            .makeSAMOrBAMWriter(
                outHeader, outHeader.getSortOrder() == inHeader.getSortOrder(), OUTPUT);

    final ProgressLogger progress = new ProgressLogger(log);
    for (final SAMRecord read : in) {
      read.setAttribute(SAMTag.RG.name(), RGID);
      outWriter.addAlignment(read);
      progress.record(read);
    }

    // cleanup
    in.close();
    outWriter.close();
    return 0;
  }
 @Override
 public void add(GATKSAMRecord read) {
   bamWriter.addAlignment(read);
 }