ISP

In short: The interface segregation principle (ISP) states: many small, specific interfaces are better than one large one.

In more detail: The “I” in SOLID. No client should depend on methods it does not use.

In Depth

Example

An interface Machine with print(), scan(), fax() forces a simple printer to implement empty methods. Better: Printer, Scanner, Fax separately and combined when needed.

Not to be confused with ISP (internet service provider, see internet service provider). See interface, SRP.

See also: SOLID-Prinzipien, Interface, SRP, DIP