docs: public void connecDataSet(IntermediateDataSet dataSet) {
  		if (dataSet == null) {
  			throw new NullPointerException();
  		}
  		if (this.source != null) {
  			throw new IllegalStateException("The edge is already connected.");
  		}
  		if (!dataSet.getId().equals(sourceId)) {
  			throw new IllegalArgumentException("The data set to connect does not match the sourceId.");
  		}
  		
  		this.source = dataSet;
  	}