Pemodelan kelas sing apik tegese kelas sing peta menyang konsep domain sing nyata, saben-saben kanthi siji tanggung jawab sing jelas, ana hubungan is-a/has-a sing jujur, lan gumantung ing abstraksi ing wates. Ora ana rumus, nanging ana proses sing bisa diulang.
Proses praktis
1. Find the NOUNS → candidate classes (Order, Customer, Payment)
2. Find the VERBS → candidate behaviors/methods (place, refund, ship)
3. Assign each behavior to the class that OWNS the data it needs (high cohesion)
4. Choose relationships: IS-A (rare, must pass LSP) vs HAS-A (default)
5. Depend on interfaces at boundaries (DIP); inject volatile dependencies
6. Keep invariants inside the object (encapsulation); prefer immutability for values
