dnet-hadoop/dhp-workflows/dhp-doiboost/src/main/java/eu/dnetlib/doiboost/crossref/CrossrefDataset.scala

94 lines
2.6 KiB
Scala

package eu.dnetlib.doiboost.crossref
import eu.dnetlib.dhp.application.ArgumentApplicationParser
import org.apache.commons.io.IOUtils
import org.apache.spark.SparkConf
import org.apache.spark.sql.expressions.Aggregator
import org.apache.spark.sql.{Dataset, Encoder, Encoders, SaveMode, SparkSession}
import org.json4s
import org.json4s.DefaultFormats
import org.json4s.jackson.JsonMethods.parse
import org.slf4j.{Logger, LoggerFactory}
object CrossrefDataset {
def extractTimestamp(input:String): Long = {
implicit lazy val formats: DefaultFormats.type = org.json4s.DefaultFormats
lazy val json: json4s.JValue = parse(input)
(json\"indexed"\"timestamp").extractOrElse[Long](0)
}
def main(args: Array[String]): Unit = {
val logger: Logger = LoggerFactory.getLogger(SparkMapDumpIntoOAF.getClass)
val conf: SparkConf = new SparkConf()
val parser = new ArgumentApplicationParser(IOUtils.toString(CrossrefDataset.getClass.getResourceAsStream("/eu/dnetlib/dhp/doiboost/crossref_to_dataset_params.json")))
parser.parseArgument(args)
val spark: SparkSession =
SparkSession
.builder()
.config(conf)
.appName(SparkMapDumpIntoOAF.getClass.getSimpleName)
.master(parser.get("master")).getOrCreate()
import spark.implicits._
val crossrefAggregator = new Aggregator[CrossrefDT, CrossrefDT, CrossrefDT] with Serializable {
override def zero: CrossrefDT = null
override def reduce(b: CrossrefDT, a: CrossrefDT): CrossrefDT = {
if (b == null)
return a
if (a == null)
return b
val tb = extractTimestamp(b.json)
val ta = extractTimestamp(a.json)
if(ta >tb) {
return a
}
b
}
override def merge(a: CrossrefDT, b: CrossrefDT): CrossrefDT = {
if (b == null)
return a
if (a == null)
return b
val tb = extractTimestamp(b.json)
val ta = extractTimestamp(a.json)
if(ta >tb) {
return a
}
b
}
override def bufferEncoder: Encoder[CrossrefDT] = implicitly[Encoder[CrossrefDT]]
override def outputEncoder: Encoder[CrossrefDT] = implicitly[Encoder[CrossrefDT]]
override def finish(reduction: CrossrefDT): CrossrefDT = reduction
}
val sourcePath:String = parser.get("sourcePath")
val targetPath:String = parser.get("targetPath")
val ds:Dataset[CrossrefDT] = spark.read.load(sourcePath).as[CrossrefDT]
ds.groupByKey(_.doi)
.agg(crossrefAggregator.toColumn)
.map(s=>s._2)
.write.mode(SaveMode.Overwrite).save(targetPath)
}
}