We currently support three classes of operators based on their input and output behavior.

• Unary: Unary operators are operators that accept a single input stream and generate a single output stream, e.g., filter, map.
• Nary: Nary operators accept multiple input streams and generate a single output stream ( all with the same or distinct schemas), e.g., join, merge.
• Exchange Operator: Exchange operators accept a single input stream and are responsible for generating multiple output streams, e.g., broadcast, and keyBy.