Flink Gelly - Type mismatch while creating graph

Question

I am new to Apache Flink and Gelly and I use the Scala API. I hava a DataSet of vertices and a DataSet of edges and I am trying to create a graph like this:

val env = ExecutionEnvironment.getExecutionEnvironment
// correct result
val edges: DataSet[Edge[Long, Long]] = (some transformations here)
//also correct result
val vertices: DataSet[Vertex[Long, String]] = (some transformations here)
//in the line below I get the errors
val graph = Graph.fromDataSet(vertices, edges, env)

And I get the following errors:

Type mismatch,expected: 
  DataSet[Vertex[NotInferedK,NotInferedVV]], actual: DataSet[Vertex[Long,String]]

Type mismatch,expected: 
  DataSet[Edges[NotInferedK,NotInferedEV]], actual: DataSet[Edge[Long,Long]]

Type mismatch,expected: 
  org.apache.flink.api.java.ExecutionEnvironment, actual: org.apache.flink.api.scala.ExecutionEnvironment

Answer 1

It looks as if you imported Graph from Gelly's Java API. Try to import the Scala version of Graph using import org.apache.flink.graph.scala.Graph. This should fix your problem.