Middle Man

Signs and Symptoms

If a class performs only one action, delegating work to another class, why does it exist at all?

Reasons for the Problem

This smell can be the result of overzealous elimination of Message Chains.

In other cases, it can be the result of the useful work of a class being gradually moved to other classes. The class remains as an empty shell that does not do anything other than delegate.

Treatment

  • If most of a method's classes delegate to another class, Remove Middle Man is in order.

Payoff

  • Less bulky code.

When to Ignore

Do not delete middle man that have been created for a reason:

  • A middle man may have been added to avoid interclass dependencies.

  • Some design patterns create middle man on purpose (such as Proxy and Decorator).