Flink Gelly extending edge class and using it in DataSet

Question

In Gelly i'm trying to make a special Edge called a Temporal edge, to make this easier i made a class called Temporaledgev3:

public class TemporalEdgev3<K, V> extends Edge<K, Tuple3<V,Integer,Integer>> {

/*
Creates new temporaledge with only null values
 */
public TemporalEdgev3() {}

/*
* Constructor to make a temporal edge version 2, has 5 input values but makes a
* typle 3 which is compatible with Gelly
* */
public TemporalEdgev3(K src, K trg, V val, Integer start, Integer end) {
    this.f0 = src;
    this.f1 = trg;
    this.f2 = new Tuple3<V,Integer,Integer>(val,start,end);
}

Now i'm trying to add these edges into a Flink DataSet so it can be used in a graph but i cannot seem to work out how. However when i use the Edge class with the same constructors it works.

Here's the code, the last line gives an error

// a temporal set created with Flink, now we need to make it into a temporal set into gelly
DataSet<Tuple5<Long,Long, Double,Integer, Integer>> temporalset = env.readCsvFile("./datasets/testdata")
        .fieldDelimiter(",")  // node IDs are separated by spaces
        .ignoreComments("%")  // comments start with "%"
        .types(Long.class,Long.class,Double.class,Integer.class,Integer.class); // read the node IDs as Longs

DataSet<TemporalEdgev3<Long,Double>> edgeset3 = temporalset.map(new MapFunction<Tuple5<Long, Long, Double, Integer, Integer>, TemporalEdgev3<Long, Double>>() {
    @Override
    public TemporalEdgev3<Long, Double> map(Tuple5<Long, Long, Double, Integer, Integer> value) throws Exception {

        return new TemporalEdgev3<Long, Double>(value.f0,value.f1,value.f2,value.f3,value.f4);
    }
});

DataSet<Edge<Long,Tuple3<Double,Integer,Integer>>> edgeset4 = temporalset.map(new MapFunction<Tuple5<Long, Long, Double, Integer, Integer>, Edge<Long, Tuple3<Double, Integer, Integer>>>() {
    @Override
    public Edge<Long, Tuple3<Double, Integer, Integer>> map(Tuple5<Long, Long, Double, Integer, Integer> value) throws Exception {
        return new Edge<Long, Tuple3<Double, Integer, Integer>>(value.f0,value.f1, new Tuple3<Double, Integer, Integer>(value.f2,value.f3,value.f4));
    }
});

Graph<Long, NullValue, Tuple3<Double,Integer,Integer>> temporalgraph = Graph.fromDataSet(edgeset4,env);

Graph<Long,NullValue, Tuple3<Double,Integer,Integer>> temporalgraph2 = Graph.fromDataSet(edgeset3,env);

The error: Wrong 1st argument type. Found: 'org.apache.flink.api.java.DataSet>', required: 'org.apache.flink.api.java.DataSet>' less...

fromDataSet
(org.apache.flink.api.java.DataSet<org.apache.flink.graph.Edge<K,EV>>,
ExecutionEnvironment)
in Graph cannot be applied
to
(org.apache.flink.api.java.DataSet<flink.gelly.school.TemporalEdgev3<java.lang.Long,java.lang.Double>>,
ExecutionEnvironment)
 
 reason: no instance(s) of type variable(s) EV, K exist so that TemporalEdgev3<Long, Double> conforms to Edge<K, EV>

Maybe i'm simply not getting how to use generic types

Answer 1

You don't need to extend the Edge type. You can simply use a Tuple3 or a custom edge value type.

Your graph declaration Graph<Long, NullValue, Tuple3<Double,Integer,Integer>> expects a DataSet<Edge<Long, Tuple3<Double,Integer,Integer>>> as the edges input. That's why your temporalgraph2 declaration works but temporalgraph doesn't.