)

// Recycler will override the internal reuse in typed handlers.
// When this is supported, the handler will not do internal pooling of objects,
// call Recycle() when the object is no longer needed.
// The recycler should handle nil pointers.
type Recycler interface {
	Recycle()
}

// MSS is a map[string]string that can be serialized.
// It is not very efficient, but it is only used for easy parameter passing.

        from.children.add(to);
        to.parents.add(from);
        List<String> cycle = findCycle(to);
        if (cycle != null) {
            // remove edge which introduced cycle
            removeEdge(from, to);
            throw new CycleDetectedException(
                    "Edge between '" + from.label + "' and '" + to.label + "' introduces to cycle in the graph", cycle);
        }
    }

    void removeEdge(Vertex from, Vertex to) {

      assertTrue(cycle.hasNext());
      assertEquals("b", cycle.next());
    }
  }

  public void testCycleOfTwoWithRemove() {
    Iterable<String> iterable = Lists.newArrayList("a", "b");
    Iterator<String> cycle = Iterators.cycle(iterable);
    assertTrue(cycle.hasNext());
    assertEquals("a", cycle.next());
    assertTrue(cycle.hasNext());
    assertEquals("b", cycle.next());
    assertTrue(cycle.hasNext());

            List<String> cycle = visitCycle(graph, Collections.singleton(to), new HashMap<>(), new LinkedList<>());
            if (cycle != null) {
                // remove edge which introduced cycle
                throw new CycleDetectedException(
                        "Edge between '" + from + "' and '" + to + "' introduces to cycle in the graph", cycle);
            }
        }
    }

    private final List<String> cycle;

    public CycleDetectedException(String message, List<String> cycle) {
        super(message);
        this.cycle = cycle;
    }

    public List<String> getCycle() {
        return cycle;
    }

    @Override
    public String getMessage() {
        return super.getMessage() + " " + String.join(" --> ", cycle);
    }

        from.children.add(to);
        to.parents.add(from);
        List<String> cycle = findCycle(to);
        if (cycle != null) {
            // remove edge which introduced cycle
            removeEdge(from, to);
            throw new CycleDetectedException(
                    "Edge between '" + from.label + "' and '" + to.label + "' introduces to cycle in the graph", cycle);
        }
    }

    void removeEdge(Vertex from, Vertex to) {

	}
	cfg.MaxWait, err = time.ParseDuration(maxWait)
	if err != nil {
		return err
	}
	cycle := env.Get(EnvCycle, kvs.GetWithDefault(Cycle, DefaultKVS))
	if cycle == "" {
		cycle = "1m"
	}
	cfg.Cycle, err = time.ParseDuration(cycle)
	if err != nil {
		return err
	}
	return nil

      assertTrue(cycle.hasNext());
      assertEquals("b", cycle.next());
    }
  }

  public void testCycleOfTwoWithRemove() {
    Iterable<String> iterable = Lists.newArrayList("a", "b");
    Iterator<String> cycle = Iterators.cycle(iterable);
    assertTrue(cycle.hasNext());
    assertEquals("a", cycle.next());
    assertTrue(cycle.hasNext());
    assertEquals("b", cycle.next());
    assertTrue(cycle.hasNext());

      createDirectedGraph("aa", "dd", "ab", "ac", "ca", "cd", "bd");

  /** A directed graph with a single cycle: a -> b -> c -> d -> a. */
  private static final SuccessorsFunction<Character> CYCLE_GRAPH =
      createDirectedGraph("ab", "bc", "cd", "da");

  /**
   * Same as {@link #CYCLE_GRAPH}, but with an extra a->c edge.
   *
   * <pre>{@code
   * |--------------|
   * v              |
   * a -> b -> c -> d

        List<String> cycle = cde.getCycle();
        assertNotNull(cycle, "Cycle should be not null");
        assertTrue(cycle.contains("a"), "Cycle contains 'a'");
        assertTrue(cycle.contains("b"), "Cycle contains 'b'");
        assertTrue(cycle.contains("c"), "Cycle contains 'c'");

        Graph graph3 = new Graph();
        addEdge(graph3, "a", "b");