code: public JobEdge getBackwardConnection(final int index) {
  
  		if (index < this.backwardEdges.size()) {
  			return this.backwardEdges.get(index);
  		}
  
  		return null;
  	}
docs: Returns the backward edge with index <code>index</code>.
  
  @param index
  the index of the edge
  @return the backward edge or <code>null</code> if no edge exists at the specified index