code: public Set<IProcessingItem> getNonEntranceProcessingItems() throws Exception {
  		Set<IProcessingItem> copiedSet = new HashSet<IProcessingItem>();
  		copiedSet.addAll(this.getProcessingItems());
  		boolean result = copiedSet.removeAll(this.getEntranceProcessingItems());
  		if (!result) {
  			throw new Exception("Failed extracting the set of non-entrance processing items");
  		}
  		return copiedSet;
  	}
docs: /*
  Gets the set of ProcessingItems, excluding EntrancePIs
  Used by SamzaConfigFactory as the config for EntrancePIs and
  normal PIs are different