Guava Graph library ElementOrder on Edges instead of Nodes

Question

I have this straight-forward Graph structure using the Guava Graph library and I'd like to understand better if that is possible to sort the adjacents/edges (not the node order). For the sake of clarification:

import com.google.common.graph.ElementOrder;
import com.google.common.graph.GraphBuilder;
import com.google.common.graph.MutableGraph;

public class MyNodeTest {

    public static void main(String[] args) {
        MutableGraph<String> graph = GraphBuilder.undirected().nodeOrder(ElementOrder.insertion()).build();

        graph.addNode("A");
        graph.addNode("C");
        graph.addNode("D");
        graph.addNode("B");
        graph.addNode("E");

        graph.putEdge("A", "B");
        graph.putEdge("A", "C");
        graph.putEdge("A", "D");
        graph.putEdge("A", "E");

        System.out.println("My default Insertion.order Nodes: " + graph.nodes());
        System.out.println("Adj. Order that I couldn't understand: " + graph.adjacentNodes("A"));
        System.out.println("Successor. Order that I couldn't understand: " + graph.successors("A"));
        System.out.println("Pred. Order that I couldn't understand: " + graph.predecessors("A"));
    }
}

My outcome is:

My default Insertion.order Nodes: [A, C, D, B, E]
Adj. Order that I couldn't understand: [D, E, B, C]
Successor. Order that I couldn't understand: [D, E, B, C]
Pred. Order that I couldn't understand: [D, E, B, C]

Without further ado, what I mean is:

Using .nodeOrder(ElementOrder.insertion()) it is possible to sort the nodes themselves. Nonetheless, I'm more interested in sorting the edges associated with a given node in a way that if I used the putEdge respectively from A with B, C, D, E the outcome is precisely this instead of the above shown.

Any insight?

Thanks in advance.

So there's no `edgeOrder` method, right? In fact, the developers of this library could easily add that feature for edges as well. I suspect they are populating `LinkedHashSet` for nodes, if `nodeOrder(ElementOrder.insertion())` is specified — mangusta, Oct 06 '19 at 20:44

score 0 · Accepted Answer · answered Oct 15 '19 at 13:01

In case someone faces the same question, here is how I solved it (disclaimer: not the optimal, but a working solution).

    MutableNetwork<String, UUID> graph = NetworkBuilder.undirected().edgeOrder(ElementOrder.insertion()).build();

    graph.addNode("A");
    graph.addNode("C");
    graph.addNode("D");
    graph.addNode("B");
    graph.addNode("E");

    graph.addEdge("A", "B", UUID.randomUUID());
    graph.addEdge("A", "C", UUID.randomUUID());
    graph.addEdge("A", "D", UUID.randomUUID());
    graph.addEdge("A", "E", UUID.randomUUID());

    System.out.println("My default Insertion.order Nodes: " + graph.nodes());
    System.out.println("Adj. Order that I couldn't understand: " + graph.adjacentNodes("A"));
    System.out.println("Successor. Order that I couldn't understand: " + graph.successors("A"));
    System.out.println("Pred. Order that I couldn't understand: " + graph.predecessors("A"));

And the results:

My default Insertion.order Nodes: [A, C, D, B, E]
Adj. Order that I couldn't understand: [B, C, D, E]
Successor. Order that I couldn't understand: [B, C, D, E]
Pred. Order that I couldn't understand: [B, C, D, E]

The MutableNetwork has the .edgeOrder(ElementOrder.insertion()) that does the trick. The cons here are associated with the K,V needed to create this data structure.

Regards

Guava Graph library ElementOrder on Edges instead of Nodes

1 Answers1