Menene jagororin da azalattun azalai?

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Accepted Answer

**Jagororin** (Java 16+) sune ƙididdigewa masu tsayi, da ba za a iya canja su ba, waɗanda ke samar da abubuwa ta atomatik, kuma **azalattun azalai** (Java 17+) suna iyakance waɗanda azalai za su iya fadada/aiwatar da nau'i. Dukkansu abubuwa na zamani da ke sa Java mafi tsarwa kuma suna ba da damar ƙarin kyau.

## Jagororin — bayanai da ba za a iya canja su ba, babu aiki

```java
// ❌ a traditional data class needs ~40 lines of boilerplate
// (fields, constructor, getters, equals, hashCode, toString)

// ✅ a record generates ALL of that automatically
public record Point(int x, int y) {}

Point p = new Point(3, 4);
p.x();              // 3 — accessor (note: x(), not getX())
p.equals(new Point(3, 4));   // true — equals() generated
p;                  // Point[x=3, y=4] — toString() generated
p.hashCode();       // generated, consistent with equals
```

Jagorin yana samar ta atomatik da abokin ciniki, masu dukkar, `equals()`, `hashCode()`, da `toString()` daga abubuwan sa. Filaye sune **final** (ba za a iya canja su ba) — jagororin an tsara su don bayyanar bayyanar, bayanai da ba za a iya canja su ba (DTOs, kimar abubuwa, haɗa-haɗa).

## Jagororin na iya samun ƙulla da hanyoyi

```java
public record Range(int min, int max) {
    public Range {                          // compact constructor — validate
        if (min > max) throw new IllegalArgumentException("min > max");
    }
    public int size() { return max - min; }  // can add methods
}
```

## Azalattun azalai — masu da karfi na haɓaka

```java
// restrict WHO can extend/implement — only the named classes
public sealed interface Shape permits Circle, Square, Triangle {}

public final class Circle implements Shape { double radius; }
public final class Square implements Shape { double side; }
public final class Triangle implements Shape { double base, height; }
// no other class can implement Shape
```

Nau'i `sealed` ya bayyane abubuwa waɗanda ba za su iya haɓaka shi ba — kuna sarrafa cikakken saitin aiwatar, wanda compiler ke tilasta. Wannan yana nuna **rufaffiyar tsari** (saitin da aka sani na bambanci).

## Sealed + jagororin + jiyya da abubuwa = kyau mai karfi

```java
// the compiler KNOWS all the cases → exhaustive switch (no default needed)
double area = switch (shape) {
    case Circle c -> Math.PI * c.radius() * c.radius();
    case Square s -> s.side() * s.side();
    case Triangle t -> 0.5 * t.base() * t.height();
    // no default needed — sealed guarantees these are ALL the cases
};
```

Domin azalai na nau'i `sealed` an san shi da iyakantacce, compiler na iya tabbatar da `switch` shine **cikakke** — kama da rashin lokaci. A gida tare da jagororin da jiyya da abubuwa, wannan yana kawo da nau'i na algebraic-data-type ga Java.

## Dalilin da yake mahalarta

Jagororin da azalattun azalai sune manyan abubuwan Java na jiya da ke tabbatar da inganta da karfi. **Jagororin** suna share abubuwan da ba za a iya joyawa ba, masu kuskure na azalai na bayanai (kuma su garantar daidai, juna ya dace na `equals`/`hashCode` — warware waccan siyya) yayin tilasta juyawa — sanya DTOs, kimar abubuwa, da nuni da data yayi mafi kyau. **Azalattun azalai** suna ba da damar rufaffiyar, sarrafa nau'i na tsari waɗanda compiler ya fahimta, wanda — a gida tare da jagororin da jiyya `switch` — yana ba da damar mun mika, babbar tinkirin saitin da aka sani na bambanci (algebraic data types).

Juna sune sanya Java mafi gaje, ba za su iya joyawa ne kuma suna da karfin amfani da tsafi na yankin nuni.

Sanin su yana nuna wuyar ya ƙarfafa Java na jiya kuma yana ba da damar mun amfani da tsarfin, jujuya nuni waɗanda Java tsohuwa ya bukaci kai tsaye yakin bada.