com.signalcollect.triplerush.sparql.TripleRushIterator.scala Maven / Gradle / Ivy

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/*
 * Copyright (C) 2015 Cotiviti Labs ([email protected])
 *
 * Licensed 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 com.signalcollect.triplerush.sparql

import org.apache.jena.graph.{ NodeFactory, Triple }
import org.apache.jena.graph.impl.LiteralLabelFactory
import org.apache.jena.datatypes.TypeMapper
import com.signalcollect.triplerush.dictionary.RdfDictionary

object TripleRushIterator {

  /**
   * Assumes queries of the form `?s ?p ?o`, where in the place of each variable there could also be an IRI or literal.
   */
  def convert(
    sOption: Option[String],
    pOption: Option[String],
    oOption: Option[String],
    dictionary: RdfDictionary,
    i: Iterator[Array[Int]]): Iterator[Triple] = {
    val sNode = sOption.map(NodeConversion.stringToNode(_))
    val pNode = pOption.map(NodeConversion.stringToNode(_))
    val oNode = oOption.map(NodeConversion.stringToNode(_))

    @inline def toTriple(r: Array[Int]): Triple = {
      var i = 0
      val s = sNode.getOrElse {
        val encodedId = r(i)
        val decodedString = dictionary(encodedId)
        val n = NodeConversion.stringToNode(decodedString)
        i += 1
        n
      }
      val p = pNode.getOrElse {
        val encodedId = r(i)
        val decodedString = dictionary(encodedId)
        val n = NodeConversion.stringToNode(decodedString)
        i += 1
        n
      }
      val o = oNode.getOrElse {
        val encodedId = r(i)
        val decodedString = dictionary(encodedId)
        NodeConversion.stringToNode(decodedString)
      }
      val triple = new Triple(s, p, o)
      triple
    }
    i.map(toTriple(_))
  }

}