Scala + Neo4j sample

neo4j-scala.scala

import org.neo4j.graphdb.RelationshipType
import org.neo4j.kernel.EmbeddedGraphDatabase
import org.neo4j.graphdb.GraphDatabaseService
import org.neo4j.graphdb.Node
import org.neo4j.graphdb.Relationship

object RelTypes extends Enumeration {
  type RelTypes = Value
  val KNOWS, MAYOR_OF = Value

  implicit def conv(rt: RelTypes) = new RelationshipType() {
    def name = rt.toString()
  }
}

import RelTypes._

object EmbeddedNeo4jScala {
  private val DB_PATH = "target/neo4j-scala-db"
  private val USERNAME_KEY = "username"
  private val graphDb: GraphDatabaseService = new EmbeddedGraphDatabase(DB_PATH)

  private def registerShutdownHook =
    Runtime.getRuntime.addShutdownHook(new Thread() {
      override def run = shutdown
    })

  private def shutdown = graphDb.shutdown

  private def createUser(username: String) = {
    val node = graphDb.createNode
    node.setProperty(USERNAME_KEY, username)
    node
  }

  private def doTx(f: GraphDatabaseService => Unit) = {
    val tx = graphDb.beginTx
    try {
      f(graphDb)
      tx.success
    } finally {
      tx.finish
    }
  }

  def main(args: Array[String]): Unit = {
    registerShutdownHook
    doTx {
      db =>
        val firstNode: Node = createUser("userOne")
        firstNode.setProperty("message", "Hello")
        val secondNode: Node = createUser("userTwo")
        secondNode.setProperty("message", "World")
        val relationship: Relationship = firstNode.createRelationshipTo(secondNode, KNOWS)
        relationship.setProperty("message", "neo4j-scala")
        println(firstNode.getProperty("message") + " " + relationship.getProperty("message") + " " + secondNode.getProperty("message"))

        val it = firstNode.getRelationships().iterator()

        while (it.hasNext()) {
          val r: Relationship = it.next()
          val nodes: Array[Node] = r.getNodes()
          println(nodes(0).getProperty("message") + " " + r.getProperty("message") + " " + nodes(1).getProperty("message"))
        }
    }
  }
}