Interface Segregation Principle Common smells and Related Design Patterns

• Liskov Substitution Principle violation smell often indicates a violation of Interface Segregation Principle
• Client's code references a [[class]] but uses only a small portion of it's [[API]]
  • Fat [[interface]] -> segregate it
  • Fat [[interface]] which is not under your control -> [[Facade design pattern]]
• Adapter Design Pattern

Tips¶

• General algorithm of "fixing" fat interfaces
  • Create narrower interface
  • Fat interface inherits from that narrow interface
  • Client uses the narrow interface
• Don't abuse ISP by creating tons of small interfaces