public int getSeriesLength() {
		return -1;
	}
For nodes representing a flow or split, return how many are in the series of things
to run (so the number to run in sequence or the number to run in parallel).

@return the length of the series for flow or split nodes, otherwise -1
spring-xd-dirt/src/main/java/org/springframework/xd/dirt/job/dsl/JobNode.java