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adam-core/src/main/scala/org/bdgenomics/adam/converters/FastaConverters.scala
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/** | ||
* Licensed to Big Data Genomics (BDG) under one | ||
* or more contributor license agreements. See the NOTICE file | ||
* distributed with this work for additional information | ||
* regarding copyright ownership. The BDG 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.bdgenomics.adam.converters | ||
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import org.apache.spark.rdd.RDD | ||
import org.apache.spark.broadcast.Broadcast | ||
import org.bdgenomics.formats.avro.{ Alphabet, Sequence, Slice } | ||
import scala.collection.immutable.SortedMap | ||
import scala.collection.mutable.MutableList | ||
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/** | ||
* FASTA format description line. | ||
* | ||
* @param index Index of the description line. | ||
* @param name Name parsed from the description line. | ||
* @param description Description parsed from the description line. | ||
*/ | ||
private[adam] case class FastaDescriptionLine( | ||
index: Long = -1L, | ||
name: Option[String] = None, | ||
description: Option[String] = None) { | ||
} | ||
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/** | ||
* FASTA format converters. | ||
*/ | ||
private[converters] object FastaConverters { | ||
// nucleotide + amino acid + ambiguity codes covers a-z | ||
private val fastaRegex = "^[a-zA-Z]+$".r // this should include '*' if indeed valid, per cleanSequence below | ||
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/** | ||
* Return true if the specified line is a description line. | ||
* | ||
* @param line FASTA format line. | ||
* @return Return true if the specified line is a description line. | ||
*/ | ||
def isDescriptionLine(line: String): Boolean = { | ||
line.startsWith(">") | ||
} | ||
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/** | ||
* Return true if the specified line is valid FASTA format. | ||
* | ||
* @param line FASTA format line. | ||
* @return Return true if the specified line is valid FASTA format. | ||
*/ | ||
def isFastaLine(line: String): Boolean = { | ||
isDescriptionLine(line) || fastaRegex.pattern.matcher(line).matches() | ||
} | ||
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/** | ||
* Cleans up a sequence by stripping asterisks at the end of the sequence. | ||
* | ||
* To be consistent with a legacy database, some FASTA sequences end in a "*" | ||
* suffix. This method strips that suffix from the end of the sequence. | ||
* | ||
* @param sequence The sequence to clean. | ||
* @return Sequence minus "*" suffix. | ||
*/ | ||
def cleanSequence(sequence: String): String = { | ||
sequence.stripSuffix("*") | ||
} | ||
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/** | ||
* Parse the specified line into a description line. | ||
* | ||
* @param index Index of the line to parse. | ||
* @param optLine Line to parse, if any. | ||
* @return Return the specified line parsed into a description line. | ||
*/ | ||
def parseDescriptionLine(index: Long, optLine: Option[String]): FastaDescriptionLine = { | ||
optLine.fold { | ||
require(index == -1L, "Cannot have a headerless line in a file with more than one sequence.") | ||
FastaDescriptionLine(index, None, None) | ||
} { | ||
(line) => | ||
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// fasta description line splits on whitespace | ||
val splitIndex = line.indexWhere(c => c.isWhitespace) | ||
if (splitIndex >= 0) { | ||
val split = line.splitAt(splitIndex) | ||
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// is this description metadata or not? if it is metadata, it will contain "|" | ||
if (split._1.contains('|')) { | ||
FastaDescriptionLine(index, None, Some(line.stripPrefix(">").trim)) | ||
} else { | ||
val name: String = split._1.stripPrefix(">").trim | ||
val description: String = split._2.trim | ||
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FastaDescriptionLine(index, Some(name), Some(description)) | ||
} | ||
} else { | ||
FastaDescriptionLine(index, Some(line.stripPrefix(">").trim), None) | ||
} | ||
} | ||
} | ||
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def filterToFastaLines(rdd: RDD[(Long, String)]): RDD[(Long, String)] = { | ||
rdd | ||
.map(kv => (kv._1, kv._2.trim())) | ||
.filter((kv: (Long, String)) => isFastaLine(kv._2)) | ||
} | ||
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def collectDescriptionLines(rdd: RDD[(Long, String)]): SortedMap[Long, FastaDescriptionLine] = { | ||
val descriptionLines: SortedMap[Long, FastaDescriptionLine] = SortedMap() | ||
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descriptionLines ++ rdd // Scala 2.13+ only SortedMap.from( | ||
.filter(kv => isDescriptionLine(kv._2)) | ||
.map(kv => (kv._1, parseDescriptionLine(kv._1, Some(kv._2)))) | ||
.sortByKey() // not strictly necessary, slightly slower without | ||
.collect() | ||
} | ||
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def groupByDescriptionLineIndex(rdd: RDD[(Long, String)], broadcast: Broadcast[SortedMap[Long, FastaDescriptionLine]]): RDD[(Long, Iterable[(Long, String)])] = { | ||
rdd | ||
.filter(kv => !isDescriptionLine(kv._2)) | ||
//.keyBy(kv => broadcast.value.maxBefore(kv._1).getOrElse(-1L)) Scala 2.13+ only | ||
.keyBy(kv => broadcast.value.until(kv._1).lastOption.getOrElse((-1L, Nil))._1) | ||
.groupByKey() | ||
} | ||
} | ||
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/** | ||
* Convert FASTA format into Sequences. | ||
*/ | ||
private[adam] object FastaSequenceConverter { | ||
import FastaConverters._ | ||
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/** | ||
* Convert FASTA format into Sequences. | ||
* | ||
* @param alphabet Alphabet for the sequences. | ||
* @param rdd RDD of FASTA format as (Long, String) tuples. | ||
* @return An RDD of Sequences converted from FASTA format. | ||
*/ | ||
def apply(alphabet: Alphabet, rdd: RDD[(Long, String)]): RDD[Sequence] = { | ||
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val filtered = filterToFastaLines(rdd) | ||
val descriptionLines = collectDescriptionLines(filtered) | ||
val broadcast = rdd.context.broadcast(descriptionLines) | ||
val sequenceLines = groupByDescriptionLineIndex(filtered, broadcast) | ||
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sequenceLines.flatMap { | ||
case (index: Long, lines) => | ||
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val descriptionLine = broadcast.value.getOrElse(index, FastaDescriptionLine()) | ||
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val sequence = lines.toSeq.sortBy(_._1).map(kv => cleanSequence(kv._2)).mkString | ||
val length = sequence.length().toLong | ||
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val builder = Sequence.newBuilder() | ||
.setAlphabet(alphabet) | ||
.setSequence(sequence) | ||
.setLength(length) | ||
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// map over optional fields | ||
descriptionLine.name.foreach(builder.setName(_)) | ||
descriptionLine.description.foreach(builder.setDescription(_)) | ||
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Seq(builder.build) | ||
} | ||
} | ||
} | ||
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/** | ||
* Convert FASTA format into Slices. | ||
*/ | ||
private[adam] object FastaSliceConverter { | ||
import FastaConverters._ | ||
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/** | ||
* Convert FASTA format into Slices. | ||
* | ||
* @param rdd RDD of FASTA format as (Long, String) tuples. | ||
* @param maximumLength Maximum length in bases for each Slice. | ||
* @return An RDD of Slices converted from FASTA format. | ||
*/ | ||
def apply(rdd: RDD[(Long, String)], maximumLength: Long): RDD[Slice] = { | ||
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val filtered = filterToFastaLines(rdd) | ||
val descriptionLines = collectDescriptionLines(filtered) | ||
val broadcast = rdd.context.broadcast(descriptionLines) | ||
val sequenceLines = groupByDescriptionLineIndex(filtered, broadcast) | ||
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sequenceLines.flatMap { | ||
case (index: Long, lines) => | ||
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val descriptionLine = broadcast.value.getOrElse(index, FastaDescriptionLine()) | ||
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val sequences = lines.toSeq.sortBy(_._1).map(kv => cleanSequence(kv._2)) | ||
val length = sequences.map(_.length).sum | ||
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val sequenceSlices = slice(sequences, maximumLength) | ||
val sliceCount = sequenceSlices.length | ||
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val slices = sequenceSlices.zipWithIndex | ||
.map(si => { | ||
val (bases, index) = si | ||
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val builder = Slice.newBuilder() | ||
.setAlphabet(Alphabet.DNA) | ||
.setSequence(bases) | ||
.setIndex(index) | ||
.setStart(index * maximumLength) | ||
.setEnd(index * maximumLength + bases.length) | ||
.setSlices(sliceCount) | ||
.setLength(bases.length.toLong) | ||
.setTotalLength(length.toLong) | ||
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// map over optional fields | ||
descriptionLine.name.foreach(builder.setName(_)) | ||
descriptionLine.description.foreach(builder.setDescription(_)) | ||
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builder.build | ||
}) | ||
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slices | ||
} | ||
} | ||
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private def slice(sequences: Seq[String], maximumLength: Long): Seq[String] = { | ||
// internal "fsm" variables | ||
var sequence: StringBuilder = new StringBuilder | ||
var sequenceSeq: MutableList[String] = MutableList() | ||
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/** | ||
* Adds a string slice to our accumulator. If this string slice causes the accumulator | ||
* to grow longer than our max slice size, we split the accumulator and add it to the end | ||
* of our list of slice. | ||
* | ||
* @param seq Slice string to add. | ||
*/ | ||
def addSlice(seq: String) { | ||
sequence.append(seq) | ||
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while (sequence.length > maximumLength) { | ||
sequenceSeq += sequence.take(maximumLength.toInt).toString() | ||
sequence = sequence.drop(maximumLength.toInt) | ||
} | ||
} | ||
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// run addFragment on all slices | ||
sequences.foreach(addSlice) | ||
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// if we still have a remaining sequence that is not part of a slice, add it | ||
if (sequence.nonEmpty) { | ||
sequenceSeq += sequence.toString() | ||
} | ||
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// return our slices | ||
sequenceSeq | ||
} | ||
} |
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