Template for testing: RocksDB with Scala

StoreRocksDB.scala

import java.io.File
import org.rocksdb._
import org.rocksdb.util.SizeUnit
import scala.collection.JavaConversions._

// build.sbt
// name := "RocksDB"
// version := "0.1"
// scalaVersion := "2.12.0"
// libraryDependencies += "org.rocksdb" % "rocksdbjni" % "5.0.1"

class StoreRocksDB {
    val UTF8  : String = "UTF-8"
    var isOpen : Boolean = false
    val tmpFile = File.createTempFile("rocksdb", ".db")
    val tmpFileName = tmpFile.getAbsolutePath
    tmpFile.delete
  
    RocksDB.loadLibrary()

    var options = new Options().setCreateIfMissing(true)
    options.setCreateIfMissing(true)
            .createStatistics()
            .setWriteBufferSize(200 * SizeUnit.MB)
            .setMaxWriteBufferNumber(3)
            .setMaxBackgroundCompactions(10)
            .setCompressionType(CompressionType.SNAPPY_COMPRESSION)
            .setCompactionStyle(CompactionStyle.UNIVERSAL)
 
    // a factory method that returns a RocksDB instance
    var  store = RocksDB.open(options, tmpFileName )
    isOpen = true
    def put( k:String , v:String) = {
        assert(isOpen)
        store.put(
            k.getBytes(UTF8),
            v.getBytes(UTF8)
        )
    }

    def commit = {}

    // if l is sorted by key is better
    def putList( l : List[(String,String)])={
            assert(isOpen)
            val writeOpt = new WriteOptions()
            val batch    = new WriteBatch()
            l.foreach( ll => {
                val ( k,v) = ll
                batch.put(k.getBytes(UTF8), v.getBytes(UTF8))
            })
            store.write(writeOpt, batch)
    }


    def get( k:String) : Option[String]= {
        assert(isOpen)
        try{
            val v = store.get(k.getBytes(UTF8))
            Some(new String(v, UTF8))
        }catch{
            case e:java.lang.NullPointerException => None
        }
    }

    def shutdown = {
       store.close()
       isOpen = false
       tmpFile.delete
    }
}

/*
store.store.getProperty("rocksdb.cur-size-all-mem-tables")
store.store.getProperty("rocksdb.estimate-num-keys")
store.store.getProperty("rocksdb.stats")

*/