Added RDFStats example for Flink

Author: GezimSejdiu

sansa-examples-flink/src/main/scala/net/sansa_stack/examples/flink/rdf/RDFStats.scala

@@ -0,0 +1,45 @@
+package net.sansa_stack.examples.flink.rdf
+
+import scala.collection.mutable
+import java.io.File
+import org.apache.flink.api.scala.ExecutionEnvironment
+import net.sansa_stack.rdf.flink.data.RDFGraphLoader
+import net.sansa_stack.rdf.flink.stats.RDFStatistics
+
+object RDFStats {
+  def main(args: Array[String]) = {
+    if (args.length < 2) {
+      System.err.println(
+        "Usage: RDF Statistics <input> <output>")
+      System.exit(1)
+    }
+    val input = args(0) //"src/main/resources/rdf.nt"
+    val rdf_stats_file = new File(input).getName
+    val output = args(1)
+    val optionsList = args.drop(1).map { arg =>
+      arg.dropWhile(_ == '-').split('=') match {
+        case Array(opt, v) => (opt -> v)
+        case _             => throw new IllegalArgumentException("Invalid argument: " + arg)
+      }
+    }
+    val options = mutable.Map(optionsList: _*)
+
+    options.foreach {
+      case (opt, _) => throw new IllegalArgumentException("Invalid option: " + opt)
+    }
+    println("======================================")
+    println("|        RDF Statistic example       |")
+    println("======================================")
+
+    val env = ExecutionEnvironment.getExecutionEnvironment
+
+    val rdfgraph = RDFGraphLoader.loadFromFile(input, env)
+
+    // compute  criterias
+    val rdf_statistics = RDFStatistics(rdfgraph, env)
+    val stats = rdf_statistics.run()
+    rdf_statistics.voidify(stats, rdf_stats_file, output)
+
+  }
+
+}