Github user manuzhang commented on a diff in the pull request:
https://github.com/apache/incubator-gearpump/pull/223#discussion_r138884320
--- Diff: core/src/main/scala/org/apache/gearpump/util/Graph.scala ---
@@ -355,19 +393,7 @@ class Graph[N, E](vertexList: List[N], edgeList:
List[(N, E, N)]) extends Serial
* check whether there is a loop
*/
def hasCycle(): Boolean = {
- @tailrec
- def detectCycle(graph: Graph[N, E]): Boolean = {
- if (graph.edges.isEmpty) {
- false
- } else if (graph.vertices.nonEmpty &&
!graph.vertices.exists(graph.inDegreeOf(_) == 0)) {
- true
- } else {
- graph.removeZeroInDegree
- detectCycle(graph)
- }
- }
-
- detectCycle(copy)
+ tryTopologicalOrderIterator.isFailure
--- End diff --
sure, this can be left as a future optimization and I'm not a big fan of
"mutable"
---
