refactor: Refactor dijkstra algorithm to make which depends on graph …

…interface

issue: #287

integration/service/oasis/stationgraph/dijkstra.go

@@ -0,0 +1,43 @@
+package stationgraph
+
+import "github.com/golang/glog"
+
+// dijkstra accepts IGraph and returns all node ids in the shortest path, except start node and end node
+func dijkstra(g IGraph) []nodeID {
+	m := newQueryHeap()
+
+	// init
+	m.add(g.StartNodeID(), invalidNodeID, 0, 0)
+
+	for {
+		currID := m.next()
+
+		// stop condition
+		if currID == invalidNodeID {
+			glog.Warning("PriorityQueue is empty before solution is found.")
+			return nil
+		}
+		if currID == g.EndNodeID() {
+			return m.retrieve(currID)
+		}
+
+		// relax
+		node := g.Node(currID)
+		for _, targetID := range g.AdjacentList(currID) {
+			if g.Edge(currID, targetID) == nil {
+				glog.Errorf("No connectivity between %#v and %#v which is unexpected, check your logic.\n", currID, targetID)
+			}
+
+			len := g.Edge(currID, targetID).distance
+			t := g.Edge(currID, targetID).duration
+
+			if g.Node(currID).reachableByDistance(len) {
+				chargeTimeNeeded := g.Node(targetID).calcChargeTime(node, len, g.ChargeStrategy())
+				if m.add(targetID, currID, len, chargeTimeNeeded+t) {
+					g.Node(targetID).updateArrivalEnergy(node, len)
+					g.Node(targetID).updateChargingTime(chargeTimeNeeded)
+				}
+			}
+		}
+	}
+}