code: public EntranceProcessingItem setOutputStream(Stream outputStream) {
  		if (this.outputStream != null && this.outputStream != outputStream) {
  			throw new IllegalStateException("Cannot overwrite output stream of EntranceProcessingItem");
  		} else 
  			this.outputStream = outputStream;
  		return this;
  	}
docs: Set the output stream of this EntranceProcessingItem.
  An EntranceProcessingItem should have only 1 single output stream and
  should not be re-assigned.
  @return this EntranceProcessingItem