add .interval_list file parser

adam-core/src/main/scala/org/bdgenomics/adam/rdd/ADAMContext.scala

@@ -370,6 +370,26 @@ class ADAMContext(val sc: SparkContext) extends Serializable with Logging {
     if (Metrics.isRecording) records.instrument() else records
   }
 
+  def loadIntervalList(filePath: String): RDD[Feature] = {
+    val parsedLines = sc.textFile(filePath).map(new IntervalListParser().parse)
+    val (seqDict, records) = (SequenceDictionary(parsedLines.flatMap(_._1).collect(): _*), parsedLines.flatMap(_._2))
+    val seqDictMap = seqDict.records.map(sr => sr.name -> sr).toMap
+    val recordsWithContigs = for {
+      record <- records
+      seqRecord <- seqDictMap.get(record.getContig.getContigName)
+    } yield Feature.newBuilder(record)
+      .setContig(
+        Contig.newBuilder()
+          .setContigName(seqRecord.name)
+          .setReferenceURL(seqRecord.url.getOrElse(null))
+          .setContigMD5(seqRecord.md5.getOrElse(null))
+          .setContigLength(seqRecord.length)
+          .build()
+      )
+      .build()
+    if (Metrics.isRecording) recordsWithContigs.instrument() else recordsWithContigs
+  }
+
   def loadParquetFeatures(
     filePath: String,
     predicate: Option[FilterPredicate] = None,
@@ -418,18 +438,21 @@ class ADAMContext(val sc: SparkContext) extends Serializable with Logging {
     projection: Option[Schema] = None): RDD[Feature] = {
 
     if (filePath.endsWith(".bed")) {
-      log.info("Loading " + filePath + " as BED and converting to features. Projection is ignored.")
+      log.info(s"Loading $filePath as BED and converting to features. Projection is ignored.")
       loadBED(filePath)
     } else if (filePath.endsWith(".gtf") ||
       filePath.endsWith(".gff")) {
-      log.info("Loading " + filePath + " as GTF/GFF and converting to features. Projection is ignored.")
+      log.info(s"Loading $filePath as GTF/GFF and converting to features. Projection is ignored.")
       loadGTF(filePath)
     } else if (filePath.endsWith(".narrowPeak") ||
       filePath.endsWith(".narrowpeak")) {
-      log.info("Loading " + filePath + " as NarrowPeak and converting to features. Projection is ignored.")
+      log.info(s"Loading $filePath as NarrowPeak and converting to features. Projection is ignored.")
       loadNarrowPeak(filePath)
+    } else if (filePath.endsWith(".interval_list")) {
+      log.info(s"Loading $filePath as IntervalList and converting to features. Projection is ignored.")
+      loadIntervalList(filePath)
     } else {
-      log.info("Loading " + filePath + " as Parquet containing Features.")
+      log.info(s"Loading $filePath as Parquet containing Features.")
       loadParquetFeatures(filePath, None, projection)
     }
   }

adam-core/src/main/scala/org/bdgenomics/adam/rdd/Coverage.scala

@@ -147,6 +147,7 @@ class Coverage(val window: Long) extends Serializable {
             OrientedPoint(r1.referenceName, r1.end, false),
             OrientedPoint(r2.referenceName, r2.start, true))
         }
+      case _ => Seq()
     }
     val paired = points.pair()
     val pairedAndFiltered = paired.filter(p =>

adam-core/src/main/scala/org/bdgenomics/adam/rdd/features/FeatureParser.scala

@@ -19,7 +19,8 @@ package org.bdgenomics.adam.rdd.features
 
 import java.io.File
 import java.util.UUID
-import org.bdgenomics.formats.avro.{ Contig, Strand, Feature }
+import org.bdgenomics.adam.models.SequenceRecord
+import org.bdgenomics.formats.avro.{ Dbxref, Contig, Strand, Feature }
 import scala.collection.JavaConversions._
 import scala.collection.mutable.ArrayBuffer
 
@@ -118,6 +119,72 @@ class GTFParser extends FeatureParser {
   }
 }
 
+class IntervalListParser extends Serializable {
+  def parse(line: String): (Option[SequenceRecord], Option[Feature]) = {
+    val fields = line.split("[ \t]+")
+    if (fields.length < 2) {
+      (None, None)
+    } else {
+      if (fields(0).startsWith("@")) {
+        if (fields(0).startsWith("@SQ")) {
+          val (name, length, url, md5) = {
+            val attrs = fields.drop(1).map(field => field.split(":", 2) match {
+              case Array(key, value) => key -> value
+              case x                 => throw new Exception(s"Expected fields of the form 'key:value' in field $field but got: $x. Line:\n$line")
+            }).toMap
+
+            // Require that all @SQ lines have name, length, url, md5.
+            (attrs("SN"), attrs("LN").toLong, attrs("UR"), attrs("M5"))
+          }
+
+          (Some(SequenceRecord(name, length, md5, url)), None)
+        } else {
+          (None, None)
+        }
+      } else {
+        if (fields.length < 4) {
+          throw new Exception(s"Invalid line: $line")
+        }
+
+        val (dbxrfs, attrs: Map[String, String]) =
+          (if (fields.length < 5 || fields(4) == "." || fields(4) == "-") {
+            (Nil, Map())
+          } else {
+            val a = fields(4).split(Array(';', ',')).map(field => field.split('|') match {
+              case Array(key, value) =>
+                key match {
+                  case "gn" | "ens" | "vega" | "ccds" => (Some(Dbxref.newBuilder().setDb(key).setAccession(value).build()), None)
+                  case _                              => (None, Some(key -> value))
+                }
+              case x => throw new Exception(s"Expected fields of the form 'key|value;' but got: $field. Line:\n$line")
+            })
+
+            (a.flatMap(_._1).toList, a.flatMap(_._2).toMap)
+          })
+
+        (
+          None,
+          Some(
+            Feature.newBuilder()
+              .setContig(Contig.newBuilder().setContigName(fields(0)).build())
+              .setStart(fields(1).toLong)
+              .setEnd(fields(2).toLong)
+              .setStrand(fields(3) match {
+                case "+" => Strand.Forward
+                case "-" => Strand.Reverse
+                case _   => Strand.Independent
+              })
+              .setAttributes(attrs)
+              .setDbxrefs(dbxrfs)
+              .build()
+          )
+        )
+      }
+    }
+  }
+
+}
+
 class BEDParser extends FeatureParser {
 
   override def parse(line: String): Seq[Feature] = {