Me yasa a fi ma'auni akan haɗawa akan gida?

Question

Accepted Answer

**Haɗawa akan gida akan haɗi** shine ka'idar ƙera da aka ambaci sosai — nai da gida a bisa **haɗewa halin aiki** (haɗawa akan gida) maimakon gida daga azuzuwan tushe (gida). Gida yana da ƙananan matsaloli da haɗawa akan gida ke kauce, koda duk daya suna da wurarsu.

## Gida da haɗawa akan gida

```text
INHERITANCE → a class EXTENDS another, inheriting its behavior ("IS-A" relationship):
  class Dog extends Animal
COMPOSITION → a class is BUILT FROM other objects/behaviors ("HAS-A" / uses):
  class Car { constructor() { this.engine = new Engine(); } }   // composes behaviors
→ composition: combine smaller pieces; inheritance: derive from a parent
```

## Me yasa gida yana da matsaloli

```text
✗ TIGHT COUPLING → subclasses are tightly bound to their parent's implementation (changes
  to the parent can break subclasses — the "fragile base class" problem)
✗ RIGID hierarchies → deep/wide inheritance trees become hard to change and understand
✗ Inflexible → a class can usually only inherit from ONE parent; behavior is fixed at compile
  time; hard to combine behaviors from multiple sources
✗ Forces an "IS-A" relationship that may not truly hold; exposes parent internals
```

## Me yasa haɗawa akan gida yafi kyau

```text
✓ FLEXIBLE → compose behaviors as needed; combine multiple behaviors; change at RUNTIME
✓ LOOSE COUPLING → objects depend on interfaces of composed parts, not parent implementations
✓ REUSABLE → small, focused components reused in many combinations
✓ Easier to change/test; avoids fragile hierarchies; favors small, focused pieces
→ many patterns (Strategy, Decorator) use composition; "favor composition over inheritance"
  ⚠️ inheritance still has valid uses (true IS-A, sharing interface) → use it appropriately
```

## Me yasa ya daɗi

Sanin me yasa a fi ma'auni akan haɗawa akan gida akan gida shine ilimin da aka fi sani saboda shine **ainiyin matsakaicin ƙera** da ke inganta mahimmancewa da kula da jiyya, yana nuna azancin ƙera na jiya.

Ka'idar "bale haɗawa akan gida akan gida" tana da sani sosai saboda gida, ko da yake wani ainiyin bangaren OO, yana da ƙananan matsaloli sosai.

Sanin **bambancin" (gida a matsayin "IS-A" dangantaka fadada guida, haɗawa akan gida a matsayin "HAS-A" dangantaka gina daga wasu abubuwa) shine tushen ilimi.

Sanin **me yasa gida yana da matsaloli** shine muhimmin tunani: **damre mai karfi** (azuzuwan jiye da aka ɗauke ga aiwatarwa ta jiyensu, tare da jiyensu ta canja azuzuwa - matsalar tushen gida mai rauni), **kamanni da tasiri** (zurfin zuwan gida ta karfin karfin jiyi zunubi ya zama wuya a canja sansi), **rashin danɗalewa** (yawancin lokaci sai gida ɗaya kawai, aiki da aka sa a lokacin aika, wuya haɗewa aiki daga tushe masu yawa), da karɓawar IS-A dangantaka da barin ba daidai ba.

Wadannan shine ainiyin matsaloli masu karfi da ke haifar da wahalar kada a canja.

Sanin **me yasa haɗawa akan gida yafi kyau** — **danɗalewa** (haɗewa da haɗewa halin aiki kamar yadda ake buƙata, canja a lokaci na aiki), **damre mai karfi** (dogaje kan interfaces na haɗawar sassa maimakon aiwatarwa ta jiyensu), **sake amfani** (karamun sassa da suka daidaita sake amfani a yawa), da sauƙin canja da gwadawa — bayyana me yasa haɗawa akan gida ke kauce gida matsaloli.

Sanin cewa yawancin tsare (Strategy, Decorator) suna amfani haɗawa akan gida, yayin da gida ma yana da ainiyin amfani (daidai IS-A dangantaka, raba interfaces), nuna sautin daidaito — haɗawa akan gida shine *yawancin lokaci* nai, amma gida yana da wurinsa.

Wadannan ka'idar shine ainiyi ga danɗalewa, kula da jiyya ƙera.

Saboda "bale haɗawa akan gida akan gida" shine ainiyin, ka'idar ƙera da aka ambaci sosai, kuma saboda sanin gida na matsaloli (damre, rigidity, rashin danɗalewa) da fa'idar haɗawa akan gida (danɗalewa, damre mai karfi, sake amfani) — yayin da sanin ainiyin amfani gida — nuna sautin daidaito sanin ƙera (nai haɗawa akan gida yayin sanin wurin gida) wanda ake buƙata daga ƙarami masu gida - ilimin da aka fi sani sanin me yasa a fi ma'auni akan haɗawa akan gida akan gida shine ilimin da aka fi sani — ainiyin matsakaicin ƙera don danɗalewa, kula da jiyya ƙera, ƙarami sa ƙarami tsare, da nuni sautin sanin ƙera (nai haɗawa akan gida yayin sanin gida) da ake buƙata daga ƙarami masu tsare da rubutu ƙera mai kyau .