net.sansa_stack.owl.spark.writers.NQuadsWriter.scala Maven / Gradle / Ivy

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package net.sansa_stack.owl.spark.writers
import java.io.{BufferedWriter, ByteArrayOutputStream, OutputStreamWriter, PrintWriter}

import net.sansa_stack.owl.spark.rdd.OWLAxiomsRDD
import org.eclipse.rdf4j.rio.nquads.{NQuadsWriter => RioNQuadsWriter}
import org.semanticweb.owlapi.apibinding.OWLManager
import org.semanticweb.owlapi.formats.NQuadsDocumentFormat
import org.semanticweb.owlapi.model._

import scala.collection.JavaConverters._

object NQuadsWriter extends OWLWriterBase {
  override def save(filePath: String, owlAxioms: OWLAxiomsRDD): Unit = {
    owlAxioms.mapPartitionsWithIndex((idx: Int, partition: Iterator[OWLAxiom]) => if (partition.hasNext) {
      partition.zipWithIndex.map(axiomWIdx => {
        val axiom: OWLAxiom = axiomWIdx._1
        val axiomIdx = axiomWIdx._2

        // writer stuff...
        val os = new ByteArrayOutputStream()
        val osWriter = new OutputStreamWriter(os)
        val buffPrintWriter = new PrintWriter(new BufferedWriter(osWriter))

        val man = OWLManager.createOWLOntologyManager()
        val config = new OWLOntologyWriterConfiguration
        config.withBannersEnabled(false)
        config.withIndenting(false)
        config.withLabelsAsBanner(false)
        config.withUseNamespaceEntities(false)
        man.setOntologyWriterConfiguration(config)
        val ont = man.createOntology(Seq(axiom).asJava)

        val renderer = new SANSARioRenderer(
          ont,
          new RioNQuadsWriter(new PrintWriter(new BufferedWriter(osWriter))),
          new NQuadsDocumentFormat) {
          override def writeBanner(name: String): Unit = None
          override def writeAnnotationPropertyComment(prop: OWLAnnotationProperty): Unit = None
          override def writeClassComment(cls: OWLClass): Unit = None
          override def writeDataPropertyComment(prop: OWLDataProperty): Unit = None
          override def writeIndividualComments(ind: OWLNamedIndividual): Unit = None
          override def writeDatatypeComment(datatype: OWLDatatype): Unit = None
          override def writeObjectPropertyComment(prop: OWLObjectProperty): Unit = None
        }

        renderer.render()
        buffPrintWriter.flush()

        os.toString("UTF-8")
          // make blank node IDs unique (by appending the axiom and partition ID)
          .replaceAll("_:genid([0-9]+)", "_:genid$1" + s"_${axiomIdx}_$idx")
          .replaceAll("^\\s*#.*", "").replaceAll("\n\\s*#.*", "").trim
      })

    } else {
      Iterator()
    }).saveAsTextFile(filePath)
  }
}