Yaya za ka ƙirƙira yankin kasua cikin azuzuwan da suke da kyau?

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Kyakkyawan tsarin azuzu yana nufin azuzuwan da ke haɗa zuwa ainihin ra'ayoyin kasua, kowa da **direwa ɗaya a fili**, wanda aka haɗa ta hanyar gaskiya ta **is-a/has-a**, da kuma gaya-giɗa akan **abstraction** a iyokan gida. Babu wata tsari, amma akwai tsarin da za a iya maimaita. ## Tsarin aiki ```text 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 ``` ## Hali ya bi ba da ```java // ❌ logic separated from data (anemic) → low cohesion class Order { List items; } class OrderCalculator { double total(Order o) {...} } // ✅ behavior lives with the data it operates on class Order { private final List items; public Money total() { // owns its own rule return items.stream().map(Item::price).reduce(Money.ZERO, Money::plus); } } ``` ## Nau'ukan tunani da ke kiyaye hierarchies lafiya | Tunani | Me ya sa | |---|---| | Fi haɗin gaya; yi amfani da inheritance ne kawai don ainihin is-a | Yada tsoron fragile base class / LSP damuwai | | Kiyaye hierarchies da ƙarami (2–3 mataki) | Jigon itacen mai zurfi yana ɗauke da kowa | | Ɗaya sanin canji per azuzu (SRP) | Daidaita canji | | Rubuce zuwa interfaces a iyokan kurkuku | Gwaji, swap-ability | | Sanya value objects jingina | Kawar da nau'in kuskure | ## Kurakira Kada ki tsara *duka* duniya gaba. Fara ƙarami tare da azuzuwan tukwici; cire abstraction ne kawai lokacin da ainihin bambanci ya bayyana (tsarin uku). Speculative hierarchies suna da tsofowa da sauri. ## Me ya sa yana da muhimmanci Tsarin da yake nuni da kasua yana saukar da lambar ta hannu — saburwar injiniyar ta karanta `order.refund()` kuma ta fahimta kasua, ba kawai syntax ba. Jiya ta haura: azuzuwan da ke juna saurin laushi, masu shiyar danganta suna taratawa canji, don haka sifa da gyaran kuskure suna taɓa fayil kadan maimakon watse a cikin tsarin.

Tunani	Me ya sa
Fi haɗin gaya; yi amfani da inheritance ne kawai don ainihin is-a	Yada tsoron fragile base class / LSP damuwai
Kiyaye hierarchies da ƙarami (2–3 mataki)	Jigon itacen mai zurfi yana ɗauke da kowa
Ɗaya sanin canji per azuzu (SRP)	Daidaita canji
Rubuce zuwa interfaces a iyokan kurkuku	Gwaji, swap-ability
Sanya value objects jingina	Kawar da nau'in kuskure