Examples with VCFHeader htsjdk.variant.vcf.VCFHeader used on opensource projects

Example 51 with VCFHeader

use of htsjdk.variant.vcf.VCFHeader in project jvarkit by lindenb.

the class TestNg01 method getVcfHeader.

static VCFHeader getVcfHeader(final File f) {
    final VCFFileReader r = new VCFFileReader(f, false);
    final VCFHeader h = r.getFileHeader();
    r.close();
    return h;
}

Example 52 with VCFHeader

use of htsjdk.variant.vcf.VCFHeader in project jvarkit by lindenb.

the class VcfStage method buildInfoHeaderTab.

/**
 * build a table describing the INFO column
 */
private Tab buildInfoHeaderTab(final VCFHeader header) {
    final TableView<VCFInfoHeaderLine> table = new TableView<>(FXCollections.observableArrayList(header.getInfoHeaderLines()));
    table.getColumns().add(makeColumn("ID", F -> F.getID()));
    table.getColumns().add(makeColumn("Type", F -> F.getType() == null ? null : F.getType().name()));
    table.getColumns().add(makeColumn("Count", F -> F.isFixedCount() ? F.getCount() : null));
    table.getColumns().add(makeColumn("Description", F -> F.getDescription()));
    final Tab tab = new Tab("INFO", table);
    tab.setClosable(false);
    table.setPlaceholder(new Label("No INFO defined."));
    return tab;
}

Example 53 with VCFHeader

use of htsjdk.variant.vcf.VCFHeader in project jvarkit by lindenb.

the class VcfToSql method read.

private void read(File filename) throws IOException {
    /* insert ATGC */
    this.alleleTable.insert(outputWriter, null, "A");
    this.alleleTable.insert(outputWriter, null, "C");
    this.alleleTable.insert(outputWriter, null, "G");
    this.alleleTable.insert(outputWriter, null, "T");
    /* insert this sample */
    this.vcfFileTable.insert(outputWriter, null, filename);
    final SelectStmt vcffile_id = new SelectStmt(this.vcfFileTable);
    final Map<String, SelectStmt> sample2sampleid = new HashMap<String, SelectStmt>();
    final Map<String, SelectStmt> filter2filterid = new HashMap<String, SelectStmt>();
    final Map<String, SelectStmt> chrom2chromId = new HashMap<String, SelectStmt>();
    final VcfIterator r = VCFUtils.createVcfIteratorFromFile(filename);
    final VCFHeader header = r.getHeader();
    /* parse samples */
    for (final String sampleName : header.getSampleNamesInOrder()) {
        this.sampleTable.insert(outputWriter, null, sampleName);
        SelectStmt sample_id = new SelectStmt(this.sampleTable, "name", sampleName);
        sample2sampleid.put(sampleName, sample_id);
        this.sample2fileTable.insert(outputWriter, null, vcffile_id, sample_id);
    }
    /* parse filters */
    for (final VCFFilterHeaderLine filter : header.getFilterLines()) {
        this.filterTable.insert(outputWriter, null, vcffile_id, filter.getID(), filter.getValue());
        filter2filterid.put(filter.getID(), new SelectStmt(this.filterTable, "name", filter.getID()));
    }
    filter2filterid.put(VCFConstants.PASSES_FILTERS_v4, new SelectStmt(this.filterTable, "name", VCFConstants.PASSES_FILTERS_v4));
    final SAMSequenceDictionary dict = header.getSequenceDictionary();
    if (dict == null) {
        throw new RuntimeException("dictionary missing in VCF");
    }
    /* parse sequence dict */
    for (final SAMSequenceRecord ssr : dict.getSequences()) {
        this.chromosomeTable.insert(outputWriter, null, vcffile_id, ssr.getSequenceName(), ssr.getSequenceLength());
        chrom2chromId.put(ssr.getSequenceName(), new SelectStmt(this.chromosomeTable, "name", ssr.getSequenceName()));
    }
    VepPredictionParser vepPredictionParser = new VepPredictionParserFactory(header).get();
    SAMSequenceDictionaryProgress progress = new SAMSequenceDictionaryProgress(dict);
    int nVariants = 0;
    while (r.hasNext()) {
        if (this.outputWriter.checkError())
            break;
        VariantContext var = progress.watch(r.next());
        ++nVariants;
        /* insert ref allele */
        this.alleleTable.insert(outputWriter, null, var.getReference().getBaseString());
        /* insert variant */
        this.variantTable.insert(outputWriter, null, vcffile_id, nVariants, chrom2chromId.get(var.getContig()), var.getStart(), (var.hasID() ? var.getID() : null), new SelectStmt(this.alleleTable, "bases", var.getReference().getBaseString()), (var.hasLog10PError() ? var.getPhredScaledQual() : null));
        SelectStmt variant_id = new SelectStmt(variantTable);
        /* insert alternate alleles */
        for (Allele alt : var.getAlternateAlleles()) {
            /* insert alt allele */
            this.alleleTable.insert(outputWriter, null, alt.getBaseString());
            this.variant2altTable.insert(outputWriter, null, variant_id, new SelectStmt(this.alleleTable, "bases", alt.getBaseString()));
        }
        /* insert filters */
        for (final String filter : var.getFilters()) {
            if (filter2filterid.get(filter) == null) {
                throw new IOException("VCF Error: filter " + filter + " is not defined in the VCF header.");
            }
            this.variant2filters.insert(outputWriter, null, variant_id, filter2filterid.get(filter));
        }
        if (!this.ignore_info) {
            for (final VepPrediction pred : vepPredictionParser.getPredictions(var)) {
            /*
					vepPrediction.insert(
							outputWriter,
							null,
							variant_id,
							pred.getEnsemblGene(),
							pred.getEnsemblTranscript(),
							pred.getEnsemblProtein(),
							pred.getSymbol()
							);
					SelectStmt pred_id = new SelectStmt(vepPrediction);
			
					for(SequenceOntologyTree.Term t: pred.getSOTerms())
						{
						String term=t.getAcn().replace(':', '_');
						soTermTable.insert(
								outputWriter,
								null,
								term,
								t.getAcn()
								);//for bioportal compatibility
						SelectStmt term_id = new SelectStmt(soTermTable,"acn",term);
						
						vepPrediction2so.insert(
							outputWriter,
							null,
							pred_id,
							term_id
							);
						}
					*/
            }
        }
        /* insert genotypes */
        for (final String sampleName : sample2sampleid.keySet()) {
            final Genotype g = var.getGenotype(sampleName);
            if (!g.isAvailable() || g.isNoCall())
                continue;
            genotypeTable.insert(outputWriter, null, variant_id, sample2sampleid.get(sampleName), g.isCalled() ? new SelectStmt(this.alleleTable, "bases", g.getAllele(0).getBaseString()) : null, g.isCalled() ? new SelectStmt(this.alleleTable, "bases", g.getAllele(1).getBaseString()) : null, g.hasDP() ? g.getDP() : null, g.hasGQ() ? g.getGQ() : null);
        }
    }
    r.close();
}

Example 54 with VCFHeader

use of htsjdk.variant.vcf.VCFHeader in project jvarkit by lindenb.

the class VCFPredictions method doVcfToVcf.

@Override
protected int doVcfToVcf(final String inputName, final VcfIterator r, VariantContextWriter w) {
    ReferenceContig genomicSequence = null;
    try {
        LOG.info("opening REF:" + this.referenceGenomeSource);
        this.referenceGenome = new ReferenceGenomeFactory().open(this.referenceGenomeSource);
        loadKnownGenesFromUri();
        final VCFHeader header = (VCFHeader) r.getHeader();
        final ContigNameConverter contigNameConverter = ContigNameConverter.fromOneDictionary(this.referenceGenome.getDictionary());
        contigNameConverter.setOnNotFound(OnNotFound.SKIP);
        final VCFHeader h2 = new VCFHeader(header);
        addMetaData(h2);
        switch(this.outputSyntax) {
            case Vep:
                {
                    h2.addMetaDataLine(new VCFInfoHeaderLine("CSQ", VCFHeaderLineCount.UNBOUNDED, VCFHeaderLineType.String, "Consequence type as predicted by VEP" + ". Format: Allele|Feature|Feature_type|Consequence|CDS_position|Protein_position|Amino_acids|Codons"));
                    break;
                }
            case SnpEff:
                {
                    h2.addMetaDataLine(new VCFInfoHeaderLine("ANN", VCFHeaderLineCount.UNBOUNDED, VCFHeaderLineType.String, "Functional annotations: 'Allele | Annotation | Annotation_Impact | Gene_Name | Gene_ID | Feature_Type | Feature_ID | Transcript_BioType | Rank | HGVS.c | HGVS.p | cDNA.pos / cDNA.length | CDS.pos / CDS.length | AA.pos / AA.length | Distance | ERRORS / WARNINGS / INFO'"));
                    break;
                }
            default:
                {
                    final StringBuilder format = new StringBuilder();
                    for (FORMAT1 f : FORMAT1.values()) {
                        if (format.length() > 0)
                            format.append("|");
                        format.append(f.name());
                    }
                    h2.addMetaDataLine(new VCFInfoHeaderLine(TAG, VCFHeaderLineCount.UNBOUNDED, VCFHeaderLineType.String, "Prediction from " + getClass().getSimpleName() + ". Format: " + format));
                    break;
                }
        }
        w.writeHeader(h2);
        final SequenceOntologyTree soTree = SequenceOntologyTree.getInstance();
        final SequenceOntologyTree.Term so_intron = soTree.getTermByAcn("SO:0001627");
        final SequenceOntologyTree.Term so_exon = soTree.getTermByAcn("SO:0001791");
        final SequenceOntologyTree.Term so_splice_donor = soTree.getTermByAcn("SO:0001575");
        final SequenceOntologyTree.Term so_splice_acceptor = soTree.getTermByAcn("SO:0001574");
        final SequenceOntologyTree.Term so_5_prime_UTR_variant = soTree.getTermByAcn("SO:0001623");
        final SequenceOntologyTree.Term so_3_prime_UTR_variant = soTree.getTermByAcn("SO:0001624");
        final SequenceOntologyTree.Term so_splicing_variant = soTree.getTermByAcn("SO:0001568");
        final SequenceOntologyTree.Term so_stop_lost = soTree.getTermByAcn("SO:0001578");
        final SequenceOntologyTree.Term so_stop_gained = soTree.getTermByAcn("SO:0001587");
        final SequenceOntologyTree.Term so_coding_synonymous = soTree.getTermByAcn("SO:0001819");
        final SequenceOntologyTree.Term so_coding_non_synonymous = soTree.getTermByAcn("SO:0001583");
        final SequenceOntologyTree.Term so_intergenic = soTree.getTermByAcn("SO:0001628");
        final SequenceOntologyTree.Term so_nc_transcript_variant = soTree.getTermByAcn("SO:0001619");
        final SequenceOntologyTree.Term so_non_coding_exon_variant = soTree.getTermByAcn("SO:0001792");
        final SequenceOntologyTree.Term _2KB_upstream_variant = soTree.getTermByAcn("SO:0001636");
        final SequenceOntologyTree.Term _5KB_upstream_variant = soTree.getTermByAcn("SO:0001635");
        final SequenceOntologyTree.Term _5KB_downstream_variant = soTree.getTermByAcn("SO:0001633");
        final SequenceOntologyTree.Term _500bp_downstream_variant = soTree.getTermByAcn("SO:0001634");
        final SAMSequenceDictionaryProgress progress = new SAMSequenceDictionaryProgress(header);
        while (r.hasNext()) {
            final VariantContext ctx = progress.watch(r.next());
            final String normalizedContig = contigNameConverter.apply(ctx.getContig());
            final List<KnownGene> genes = new ArrayList<>();
            if (!StringUtil.isBlank(normalizedContig)) {
                for (final List<KnownGene> l2 : this.knownGenes.getOverlapping(new Interval(normalizedContig, ctx.getStart(), // 1-based
                ctx.getEnd()))) {
                    genes.addAll(l2);
                }
            }
            final List<Annotation> ctx_annotations = new ArrayList<Annotation>();
            if (genes == null || genes.isEmpty()) {
                // intergenic
                Annotation a = new Annotation();
                a.seqont.add(so_intergenic);
                ctx_annotations.add(a);
            } else {
                if (genomicSequence == null || !genomicSequence.hasName(normalizedContig)) {
                    LOG.info("getting genomic Sequence for " + normalizedContig);
                    genomicSequence = this.referenceGenome.getContig(normalizedContig);
                    if (genomicSequence == null)
                        throw new JvarkitException.ContigNotFoundInDictionary(normalizedContig, this.referenceGenome.getDictionary());
                }
                for (final KnownGene gene : genes) {
                    final GeneticCode geneticCode = GeneticCode.getStandard();
                    for (final Allele alt2 : ctx.getAlternateAlleles()) {
                        if (alt2.isNoCall())
                            continue;
                        if (alt2.isSymbolic()) {
                            LOG.warn("symbolic allele are not handled... " + alt2.getDisplayString());
                            continue;
                        }
                        if (alt2.isReference())
                            continue;
                        final Annotation annotations = new Annotation();
                        annotations.kg = gene;
                        annotations.alt2 = alt2;
                        if (gene.isNonCoding()) {
                            annotations.seqont.add(so_nc_transcript_variant);
                            continue;
                        }
                        ctx_annotations.add(annotations);
                        StringBuilder wildRNA = null;
                        ProteinCharSequence wildProt = null;
                        ProteinCharSequence mutProt = null;
                        MutedSequence mutRNA = null;
                        int position_in_cds = -1;
                        final int position = ctx.getStart() - 1;
                        if (!String.valueOf(genomicSequence.charAt(position)).equalsIgnoreCase(ctx.getReference().getBaseString())) {
                            if (isSimpleBase(ctx.getReference())) {
                                LOG.warn("Warning REF!=GENOMIC SEQ!!! at " + position + "/" + ctx.getReference());
                            }
                            continue;
                        }
                        if (gene.isPositiveStrand()) {
                            if (position < gene.getTxStart() - 2000) {
                                annotations.seqont.add(_5KB_upstream_variant);
                            } else if (position < gene.getTxStart()) {
                                annotations.seqont.add(_2KB_upstream_variant);
                            } else if (position >= gene.getTxEnd() + 500) {
                                annotations.seqont.add(_5KB_downstream_variant);
                            } else if (position >= gene.getTxEnd()) {
                                annotations.seqont.add(_500bp_downstream_variant);
                            } else if (position < gene.getCdsStart()) {
                                // UTR5
                                annotations.seqont.add(so_5_prime_UTR_variant);
                            } else if (gene.getCdsEnd() <= position) {
                                annotations.seqont.add(so_3_prime_UTR_variant);
                            } else {
                                int exon_index = 0;
                                while (exon_index < gene.getExonCount()) {
                                    final KnownGene.Exon exon = gene.getExon(exon_index);
                                    for (int i = exon.getStart(); i < exon.getEnd(); ++i) {
                                        if (i == position) {
                                            annotations.exon_name = exon.getName();
                                            if (exon.isNonCoding()) {
                                                annotations.seqont.add(so_non_coding_exon_variant);
                                            }
                                        }
                                        if (i < gene.getTxStart())
                                            continue;
                                        if (i < gene.getCdsStart())
                                            continue;
                                        if (i >= gene.getCdsEnd())
                                            break;
                                        if (wildRNA == null) {
                                            wildRNA = new StringBuilder();
                                            mutRNA = new MutedSequence(wildRNA);
                                        }
                                        if (i == position) {
                                            annotations.seqont.add(so_exon);
                                            annotations.exon_name = exon.getName();
                                            position_in_cds = wildRNA.length();
                                            annotations.position_cds = position_in_cds;
                                            // in splicing ?
                                            if (exon.isSplicing(position)) {
                                                if (exon.isSplicingAcceptor(position)) {
                                                    // SPLICING_ACCEPTOR
                                                    annotations.seqont.add(so_splice_acceptor);
                                                } else if (exon.isSplicingDonor(position)) {
                                                    // SPLICING_DONOR
                                                    annotations.seqont.add(so_splice_donor);
                                                } else // ??
                                                {
                                                    annotations.seqont.add(so_splicing_variant);
                                                }
                                            }
                                        }
                                        wildRNA.append(genomicSequence.charAt(i));
                                        if (i == position && isSimpleBase(alt2) && isSimpleBase(ctx.getReference())) {
                                            mutRNA.put(position_in_cds, alt2.getBaseString().charAt(0));
                                        }
                                        if (wildRNA.length() % 3 == 0 && wildRNA.length() > 0 && wildProt == null) {
                                            wildProt = new ProteinCharSequence(geneticCode, wildRNA);
                                            mutProt = new ProteinCharSequence(geneticCode, mutRNA);
                                        }
                                    }
                                    final KnownGene.Intron intron = exon.getNextIntron();
                                    if (intron != null && intron.contains(position)) {
                                        annotations.intron_name = intron.getName();
                                        annotations.seqont.add(so_intron);
                                        if (intron.isSplicing(position)) {
                                            if (intron.isSplicingAcceptor(position)) {
                                                annotations.seqont.add(so_splice_acceptor);
                                            } else if (intron.isSplicingDonor(position)) {
                                                annotations.seqont.add(so_splice_donor);
                                            } else // ???
                                            {
                                                annotations.seqont.add(so_splicing_variant);
                                            }
                                        }
                                    }
                                    ++exon_index;
                                }
                            }
                        } else // reverse orientation
                        {
                            if (position >= gene.getTxEnd() + 2000) {
                                annotations.seqont.add(_5KB_upstream_variant);
                            } else if (position >= gene.getTxEnd()) {
                                annotations.seqont.add(_2KB_upstream_variant);
                            } else if (position < gene.getTxStart() - 500) {
                                annotations.seqont.add(_5KB_downstream_variant);
                            } else if (position < gene.getTxStart()) {
                                annotations.seqont.add(_500bp_downstream_variant);
                            } else if (position < gene.getCdsStart()) {
                                annotations.seqont.add(so_3_prime_UTR_variant);
                            } else if (gene.getCdsEnd() <= position) {
                                annotations.seqont.add(so_5_prime_UTR_variant);
                            } else {
                                int exon_index = gene.getExonCount() - 1;
                                while (exon_index >= 0) {
                                    final KnownGene.Exon exon = gene.getExon(exon_index);
                                    for (int i = exon.getEnd() - 1; i >= exon.getStart(); --i) {
                                        if (i == position) {
                                            annotations.exon_name = exon.getName();
                                            if (exon.isNonCoding()) {
                                                annotations.seqont.add(so_non_coding_exon_variant);
                                            }
                                        }
                                        if (i >= gene.getCdsEnd())
                                            continue;
                                        if (i < gene.getCdsStart())
                                            break;
                                        if (wildRNA == null) {
                                            wildRNA = new StringBuilder();
                                            mutRNA = new MutedSequence(wildRNA);
                                        }
                                        if (i == position) {
                                            annotations.seqont.add(so_exon);
                                            position_in_cds = wildRNA.length();
                                            annotations.position_cds = position_in_cds;
                                            // in splicing ?
                                            if (exon.isSplicing(position)) {
                                                if (exon.isSplicingAcceptor(position)) {
                                                    annotations.seqont.add(so_splice_acceptor);
                                                } else if (exon.isSplicingDonor(position)) {
                                                    annotations.seqont.add(so_splice_donor);
                                                } else // ?
                                                {
                                                    annotations.seqont.add(so_splicing_variant);
                                                }
                                            }
                                            if (isSimpleBase(alt2) && isSimpleBase(ctx.getReference())) {
                                                mutRNA.put(position_in_cds, AcidNucleics.complement(alt2.getBaseString().charAt(0)));
                                            }
                                        }
                                        wildRNA.append(AcidNucleics.complement(genomicSequence.charAt(i)));
                                        if (wildRNA.length() % 3 == 0 && wildRNA.length() > 0 && wildProt == null) {
                                            wildProt = new ProteinCharSequence(geneticCode, wildRNA);
                                            mutProt = new ProteinCharSequence(geneticCode, mutRNA);
                                        }
                                    }
                                    final KnownGene.Intron intron = exon.getPrevIntron();
                                    if (intron != null && intron.contains(position)) {
                                        annotations.intron_name = intron.getName();
                                        annotations.seqont.add(so_intron);
                                        if (intron.isSplicing(position)) {
                                            if (intron.isSplicingAcceptor(position)) {
                                                annotations.seqont.add(so_splice_acceptor);
                                            } else if (intron.isSplicingDonor(position)) {
                                                annotations.seqont.add(so_splice_donor);
                                            } else // ?
                                            {
                                                annotations.seqont.add(so_splicing_variant);
                                            }
                                        }
                                    }
                                    --exon_index;
                                }
                            }
                        }
                        if (isSimpleBase(alt2) && isSimpleBase(ctx.getReference()) && wildProt != null && mutProt != null && position_in_cds >= 0) {
                            final int pos_aa = position_in_cds / 3;
                            final int mod = position_in_cds % 3;
                            annotations.wildCodon = ("" + wildRNA.charAt(position_in_cds - mod + 0) + wildRNA.charAt(position_in_cds - mod + 1) + wildRNA.charAt(position_in_cds - mod + 2));
                            annotations.mutCodon = ("" + mutRNA.charAt(position_in_cds - mod + 0) + mutRNA.charAt(position_in_cds - mod + 1) + mutRNA.charAt(position_in_cds - mod + 2));
                            annotations.position_protein = (pos_aa + 1);
                            annotations.wildAA = String.valueOf(wildProt.charAt(pos_aa));
                            annotations.mutAA = (String.valueOf(mutProt.charAt(pos_aa)));
                            annotations.seqont.remove(so_exon);
                            if (isStop(wildProt.charAt(pos_aa)) && !isStop(mutProt.charAt(pos_aa))) {
                                annotations.seqont.add(so_stop_lost);
                            } else if (!isStop(wildProt.charAt(pos_aa)) && isStop(mutProt.charAt(pos_aa))) {
                                annotations.seqont.add(so_stop_gained);
                            } else if (wildProt.charAt(pos_aa) == mutProt.charAt(pos_aa)) {
                                annotations.seqont.add(so_coding_synonymous);
                            } else {
                                annotations.seqont.add(so_coding_non_synonymous);
                            }
                        }
                    }
                }
            }
            final Set<String> info = new HashSet<String>(ctx_annotations.size());
            for (final Annotation a : ctx_annotations) {
                info.add(a.toString());
            }
            final VariantContextBuilder vb = new VariantContextBuilder(ctx);
            final String thetag;
            switch(this.outputSyntax) {
                case Vep:
                    thetag = "CSQ";
                    break;
                case SnpEff:
                    thetag = "ANN";
                    break;
                default:
                    thetag = TAG;
                    break;
            }
            vb.attribute(thetag, info.toArray());
            w.add(vb.make());
        }
        return RETURN_OK;
    } catch (Exception err) {
        LOG.error(err);
        return -1;
    } finally {
        CloserUtil.close(this.referenceGenome);
    }
}

Example 55 with VCFHeader

use of htsjdk.variant.vcf.VCFHeader in project jvarkit by lindenb.

the class VCFMerge method workUsingPeekIterator.

private int workUsingPeekIterator() {
    VariantContextWriter out = null;
    final List<PeekVCF> input = new ArrayList<PeekVCF>();
    try {
        final Set<String> genotypeSampleNames = new TreeSet<String>();
        final Set<VCFHeaderLine> metaData = new HashSet<VCFHeaderLine>();
        // get all VCF, check same dict
        for (final String arg : this.userVcfFiles) {
            LOG.info("Opening " + arg);
            final PeekVCF p = new PeekVCF(arg);
            input.add(p);
            genotypeSampleNames.addAll(p.header.getSampleNamesInOrder());
            metaData.addAll(p.header.getMetaDataInInputOrder());
            if (this.global_dictionary == null) {
                this.global_dictionary = p.header.getSequenceDictionary();
            } else if (!SequenceUtil.areSequenceDictionariesEqual(this.global_dictionary, p.header.getSequenceDictionary())) {
                throw new JvarkitException.DictionariesAreNotTheSame(this.global_dictionary, p.header.getSequenceDictionary());
            }
        }
        if (this.global_dictionary == null) {
            throw new IllegalStateException("No Dict");
        }
        // super.addMetaData(metaData);
        if (this.doNotMergeRowLines) {
            metaData.add(NO_MERGE_INFO_HEADER);
        }
        final SAMSequenceDictionaryProgress progress = new SAMSequenceDictionaryProgress(this.global_dictionary);
        out = super.openVariantContextWriter(this.outputFile);
        final VCFHeader headerOut = new VCFHeader(metaData, genotypeSampleNames);
        out.writeHeader(headerOut);
        final List<VariantContext> row = new ArrayList<VariantContext>(input.size());
        // find smallest ordered variant
        long nCountForGC = 0L;
        for (; ; ) {
            row.clear();
            for (final PeekVCF peekVcf : input) {
                final List<VariantContext> peekVcfList = peekVcf.peek();
                if (peekVcf.peek().isEmpty())
                    continue;
                final VariantContext ctx = peekVcfList.get(0);
                if (row.isEmpty()) {
                    row.addAll(peekVcfList);
                    continue;
                }
                final int cmp = this.compareChromPosRef.compare(ctx, row.get(0));
                if (cmp == 0) {
                    row.addAll(peekVcfList);
                } else if (cmp < 0) {
                    row.clear();
                    row.addAll(peekVcfList);
                }
            }
            if (row.isEmpty())
                break;
            for (final VariantContext merged : buildContextFromVariantContext(headerOut, row)) {
                out.add(progress.watch(merged));
            }
            // consumme peeked variants
            for (final PeekVCF peekVcf : input) {
                peekVcf.reset(row.get(0));
            }
            if (nCountForGC++ % 100000 == 0)
                System.gc();
        }
        for (final PeekVCF peekVcf : input) {
            peekVcf.close();
        }
        input.clear();
        CloserUtil.close(out);
        out = null;
        progress.finish();
        LOG.info("Done peek sorting");
        return RETURN_OK;
    } catch (final Exception err) {
        LOG.error(err);
        return -1;
    } finally {
        CloserUtil.close(out);
        for (final PeekVCF p : input) {
            p.close();
        }
    }
}