src/com.example.portfolio3/com/example/portfolio3/EdgeGraph.java



package com.example.portfolio3;

// origin: <https://moodle.ruc.dk/course/section.php?id=211877>

import java.util.ArrayList;
import java.util.Collection;
import java.util.HashSet;
import java.util.Set;

/// EdgeGraph - One big set of all edges in the graph
class EdgeGraph extends AbstractGraph {

    /// foo
    EdgeGraph() { }

    /// foo
    Set<Edge> edges = new HashSet<>();

    /// foo
    public void insertEdge(
        final Vertex v1, final Vertex v2, final int w
    ) {
        edges.add(new Edge(v1, v2, w));
    }

    /// foo
    public Collection<Edge> edges() {
        return edges;
    }

    /// foo
    public Collection<Edge> outEdge(final Vertex v) {
        ArrayList<Edge> outEdge = new ArrayList<>();
        for (Edge e: edges) {
            if (e.from() == v) {
                outEdge.add(e);
            }
        }

        return outEdge;
    }

    /// foo
    public Integer getWeight(final Vertex v1, final Vertex v2) {

        // linear in number of edges in the graph
        for (Edge e: edges) {
            if (e.from() == v1 && e.to() == v2) {
                return e.weight();
            }
        }

        return null;
    }
}