An object that knows too much or does too much.

TL;DR: Don't take too many responsibilities.

Problems

• Cohesion

• Coupling

Solutions

• Split responsibilities.
• Follow Single Responsibility Principle.
• Follow The Boy Scout Rule.

Examples

• Libraries

Exceptions

• Facades

Sample Code

Wrong

class Soldier {
   run(){}
   fight(){}
   driveGeneral(){}
   clean() {} 
   fire() {} 
   bePromoted() {}
   serialize() {}
   display() {} 
   persistOnDatabase() {}
   toXML() {}
   jsonDecode(){}

  //...     
  }

Right

class Soldier {
   run() {}
   fight() {}
   clean() {}    
  }

Detection

Linters can count methods and warn against a threshold.

Tags

• Cohesive

Conclusion

Libraries were fine in the 60. In Object-Oriented Programming, we will distribute responsibilities among many objects.

Also Known as

• Large Class

Relations

More info

• Wikipedia
• Refactoring Guru
• Coupling

Credits

Photo by Francisco Ghisletti on Unsplash

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This article is part of the CodeSmell Series.

Last update: 2021/06/21