Scala Wrapper for Corese KGRAM

Corese-Scala is a scala wrapper for the Corese/KGRAM project. It also provides some useful features like :

• a configuration file
• a namespace declaration helper

Usage

You must add it as a dependency to your SBT project

resolvers ++= Seq(
  "MNX Nexus (releases)" at "https://repo.mnemotix.com/repository/maven-releases/",
  "MNX Nexus (snapshots)" at "https://repo.mnemotix.com/repository/maven-snapshots/"
)

libraryDependencies += "com.mnemotix" %% "corese-scala" % "1.0-SNAPSHOT"

Configuration

corese-scala uses the Typesafe Config library to load configuration. So it is waiting for some configuration sections in an application.conf file located into the classpath.

// Reasoner configuration

kgram {
  entailment.active = true
  entailment.base = "http://ns.example.com/"
  default.graph = "default-ng"
  ext.filters = [
    ".owl",
    ".rdfs",
    ".rdf",
    ".nt",
    ".xml"
  ]
  models.dirs = [
    "path/to/your/models"
  ]
  data.dirs = [
    "path/to/your/data"
  ]
}

// List here the namespaces you want to be pre-loaded into Corese and that will be natively available to SPARQL queries
namespaces {
  entries = [
    {"prefix" : "dc", "value" : "http://purl.org/dc/elements/1.1/"},
    {"prefix" : "dcterms", "value" : "http://purl.org/dc/terms/"},
    {"prefix" : "dctypes", "value" : "http://purl.org/dc/dcmitype/"},
    {"prefix" : "foaf", "value" : "http://xmlns.com/foaf/0.1/"},
    {"prefix" : "geo", "value" : "http://www.w3.org/2003/01/geo/wgs84_pos"},
    {"prefix" : "ldp", "value" : "http://www.w3.org/ns/ldp#"},
    {"prefix" : "oa", "value" : "http://www.w3.org/ns/oa#"},
    {"prefix" : "owl", "value" : "http://www.w3.org/2002/07/owl#"},
    {"prefix" : "prov", "value" : "http://www.w3.org/ns/prov#"},
    {"prefix" : "rdf", "value" : "http://www.w3.org/1999/02/22-rdf-syntax-ns#"},
    {"prefix" : "rdfs", "value" : "http://www.w3.org/2000/01/rdf-schema#"},
    {"prefix" : "rr", "value" : "http://www.w3.org/ns/r2rml#"},
    {"prefix" : "skos", "value" : "http://www.w3.org/2004/02/skos/core#"},
    {"prefix" : "xsd", "value" : "http://www.w3.org/2001/XMLSchema-datatypes"}
  ]
}

API

The corese-scala API is pretty simple. Once the configuration is properly set, you just have to instanciate the reasoner and to ask it to load files.

    import com.mnemotix.corese.KGram
    import fr.inria.acacia.corese.api.IDatatype
    import fr.inria.edelweiss.kgram.core.Mappings
    
    import scala.concurrent.duration._
    import scala.concurrent.{Await, Future}
    import scala.util.{Failure, Success}

    val kgram:KGram = new KGram
    kgram.load() // loads files from conf
    kgram.clear() // reset the graph dropping all nodes and edges
    
    val query: String = s"""PREFIX skos: <http://www.w3.org/2004/02/skos/core#>
          |SELECT DISTINCT (count(DISTINCT ?concept) as ?c)
          |WHERE {
          |  ?concept a skos:Concept
          |}""".stripMargin
    
    val mappings: Mappings = kgram.executeSync(query) // execute a blocking SPARQL query
    mappings.get(0).getValue("?c").asInstanceOf[IDatatype].intValue()

    // execute a non blocking SPARQL query
    val futureMappings: Future[Mappings] = kgram.execute(query)
    futureMappings onComplete {
      case Success(m) => {
        m.get(0).getValue("?c").asInstanceOf[IDatatype].intValue()
      }
      case Failure(e) => e.printStackTrace
    }