public final class CustomerId {
    private final String value;

    public CustomerId(String value) {
        this.value = Objects.requireNonNull(value);
    }

    public String value() {
        return value;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (!(o instanceof CustomerId that)) return false;
        return value.equals(that.value);
    }

    @Override
    public int hashCode() {
        return value.hashCode();
    }

    @Override
    public String toString() {
        return "CustomerId[value=" + value + "]";
    }
}

public record CustomerId(String value) {
    public CustomerId {
        Objects.requireNonNull(value, "value");
        if (value.isBlank()) {
            throw new IllegalArgumentException("CustomerId must not be blank");
        }
    }
}

Nama tipe penting.
Daftar komponen penting.
Equality berbasis komponen penting.
State utama sengaja transparan.
Object identity bukan bagian dari domain semantics.

public record Money(BigDecimal amount, Currency currency) {}

Money = amount × currency

public record Width(int value) {}
public record Height(int value) {}

Width w = new Width(10);
Height h = new Height(10);

// Tidak assignable:
// Width x = h;

public record CaseKey(String tenantId, String caseNumber) {}

CaseKey a = new CaseKey("tenant-a", "CASE-001");
CaseKey b = new CaseKey("tenant-a", "CASE-001");

System.out.println(a.equals(b)); // true
System.out.println(a == b);      // false
System.out.println(a.tenantId());

public record UserName(String value) {
    public String normalized() {
        return value.trim().toLowerCase(Locale.ROOT);
    }
}

public record EmailAddress(String value) {
    public EmailAddress(String value) {
        Objects.requireNonNull(value, "value");
        String normalized = value.trim().toLowerCase(Locale.ROOT);
        if (!normalized.contains("@")) {
            throw new IllegalArgumentException("Invalid email address");
        }
        this.value = normalized;
    }
}

public record EmailAddress(String value) {
    public EmailAddress {
        Objects.requireNonNull(value, "value");
        value = value.trim().toLowerCase(Locale.ROOT);

        if (!value.contains("@")) {
            throw new IllegalArgumentException("Invalid email address");
        }
    }
}

Compact constructor cocok untuk:
- requireNonNull
- trim/normalize sederhana
- range check
- cross-component invariant

Compact constructor buruk untuk:
- query database
- call remote service
- publish event
- mutate external object
- long business workflow

public record DateRange(LocalDate startInclusive, LocalDate endExclusive) {}

public record DateRange(LocalDate startInclusive, LocalDate endExclusive) {}

public record DateRange(LocalDate endExclusive, LocalDate startInclusive) {}

new DateRange(start, end); // tetap compile jika urutan tipe sama, tetapi makna rusak

Apakah dua component berurutan punya tipe sama?
Apakah constructor call raw mudah tertukar?
Apakah perlu static factory bernama?
Apakah perlu wrapper type lebih spesifik?

public record DateRange(LocalDate startInclusive, LocalDate endExclusive) {
    public static DateRange between(LocalDate startInclusive, LocalDate endExclusive) {
        return new DateRange(startInclusive, endExclusive);
    }
}

public record StartDate(LocalDate value) {}
public record EndDate(LocalDate value) {}

public record DateRange(StartDate startInclusive, EndDate endExclusive) {}

public record OrderLines(List<String> lines) {}

List<String> list = new ArrayList<>();
list.add("A");

OrderLines orderLines = new OrderLines(list);
list.add("B");

System.out.println(orderLines.lines()); // [A, B]

public record OrderLines(List<String> lines) {
    public OrderLines {
        lines = List.copyOf(lines);
    }
}

public record Payload(byte[] bytes) {
    public Payload {
        bytes = bytes.clone();
    }

    @Override
    public byte[] bytes() {
        return bytes.clone();
    }
}

public record TenantCaseKey(String tenantId, String caseNumber) {
    public TenantCaseKey {
        requireText(tenantId, "tenantId");
        requireText(caseNumber, "caseNumber");
    }

    private static void requireText(String value, String name) {
        Objects.requireNonNull(value, name);
        if (value.isBlank()) {
            throw new IllegalArgumentException(name + " must not be blank");
        }
    }
}

public class CaseEntity {
    private final CaseId id;
    private CaseStatus status;
    private Instant updatedAt;

    public void escalate(Instant now) {
        if (status != CaseStatus.OPEN) {
            throw new IllegalStateException("Only OPEN cases can be escalated");
        }
        status = CaseStatus.ESCALATED;
        updatedAt = now;
    }
}

public record CaseEntity(CaseId id, CaseStatus status, Instant updatedAt) {}

public record Percentage(BigDecimal value) {
    public Percentage {
        Objects.requireNonNull(value, "value");
        if (value.compareTo(BigDecimal.ZERO) < 0 || value.compareTo(BigDecimal.valueOf(100)) > 0) {
            throw new IllegalArgumentException("Percentage must be between 0 and 100");
        }
        value = value.stripTrailingZeros();
    }

    public BigDecimal asRatio() {
        return value.divide(BigDecimal.valueOf(100), MathContext.DECIMAL64);
    }
}

new BigDecimal("1.0").equals(new BigDecimal("1.00")); // false

public record Amount(BigDecimal value) {
    public Amount {
        Objects.requireNonNull(value, "value");
        value = value.setScale(2, RoundingMode.UNNECESSARY);
    }
}

public record CaseResponse(
    String id,
    String status,
    String assignedOfficer,
    Instant updatedAt
) {}

Apakah field boleh null?
Apakah enum dikirim sebagai string?
Apakah timestamp pakai Instant atau LocalDateTime?
Apakah numeric money dikirim sebagai number atau string?
Apakah field baru backward compatible?

public record EscalateCaseCommand(
    CaseId caseId,
    OfficerId requestedBy,
    EscalationReason reason,
    Instant requestedAt
) {
    public EscalateCaseCommand {
        Objects.requireNonNull(caseId, "caseId");
        Objects.requireNonNull(requestedBy, "requestedBy");
        Objects.requireNonNull(reason, "reason");
        Objects.requireNonNull(requestedAt, "requestedAt");
    }
}

Command bisa divalidasi saat dibuat.
Semua dependency data eksplisit.
Tidak ada setter mutation di tengah pipeline.
Mudah dites.
Mudah dilog secara hati-hati.

public record EscalateCaseCommand(CaseId caseId, CaseRepository repository) {}

same record class
and all corresponding components equal

public record Point(int x, int y) {}

Point a = new Point(1, 2);
Point b = new Point(1, 2);

System.out.println(a.equals(b)); // true

public record ScreenPoint(int x, int y) {}
public record MapPoint(int x, int y) {}

System.out.println(new ScreenPoint(1, 2).equals(new MapPoint(1, 2))); // false

public record UserRecord(String id, String email) {
    @Override
    public boolean equals(Object o) {
        return o instanceof UserRecord that && id.equals(that.id);
    }
}

Jika equality tidak berbasis semua komponen utama, pertanyakan apakah tipe ini pantas menjadi record.

public record PersonName(String firstName, String lastName) {}

PersonName name = new PersonName(null, null); // compile dan runtime valid tanpa validasi

public record PersonName(String firstName, String lastName) {
    public PersonName {
        Objects.requireNonNull(firstName, "firstName");
        Objects.requireNonNull(lastName, "lastName");
    }
}

public record MiddleName(String value) {}

public record PersonName(
    String firstName,
    Optional<MiddleName> middleName,
    String lastName
) {
    public PersonName {
        Objects.requireNonNull(firstName, "firstName");
        middleName = Objects.requireNonNull(middleName, "middleName");
        Objects.requireNonNull(lastName, "lastName");
    }
}

public record DateRange(LocalDate startInclusive, LocalDate endExclusive) {
    public DateRange {
        Objects.requireNonNull(startInclusive, "startInclusive");
        Objects.requireNonNull(endExclusive, "endExclusive");
        if (!startInclusive.isBefore(endExclusive)) {
            throw new IllegalArgumentException("startInclusive must be before endExclusive");
        }
    }
}

public record CaseAssignment(OfficerId officerId, CaseId caseId) {
    public CaseAssignment {
        // Jangan call repository/service dari constructor value type.
        // Ini membuat construction mahal, nondeterministic, dan sulit dites.
    }
}

Record constructor: invariant intrinsik data.
Application service: invariant yang butuh repository, permission, workflow, atau external system.

public record DateRange(LocalDate startInclusive, LocalDate endExclusive) {
    public DateRange {
        Objects.requireNonNull(startInclusive, "startInclusive");
        Objects.requireNonNull(endExclusive, "endExclusive");
        if (!startInclusive.isBefore(endExclusive)) {
            throw new IllegalArgumentException("Invalid date range");
        }
    }

    public boolean contains(LocalDate date) {
        Objects.requireNonNull(date, "date");
        return !date.isBefore(startInclusive) && date.isBefore(endExclusive);
    }

    public Period lengthAsPeriod() {
        return Period.between(startInclusive, endExclusive);
    }
}

new Money(new BigDecimal("100.00"), Currency.getInstance("USD"));

public record Money(BigDecimal amount, Currency currency) {
    public Money {
        Objects.requireNonNull(amount, "amount");
        Objects.requireNonNull(currency, "currency");
        amount = amount.setScale(currency.getDefaultFractionDigits(), RoundingMode.UNNECESSARY);
    }

    public static Money usd(String amount) {
        return new Money(new BigDecimal(amount), Currency.getInstance("USD"));
    }
}

public interface DomainEvent {
    Instant occurredAt();
}

public record CaseEscalated(
    CaseId caseId,
    EscalationReason reason,
    Instant occurredAt
) implements DomainEvent {
    public CaseEscalated {
        Objects.requireNonNull(caseId, "caseId");
        Objects.requireNonNull(reason, "reason");
        Objects.requireNonNull(occurredAt, "occurredAt");
    }
}

public sealed interface CaseEvent permits CaseOpened, CaseEscalated, CaseClosed {}

public record CaseOpened(CaseId caseId, Instant occurredAt) implements CaseEvent {}
public record CaseEscalated(CaseId caseId, Instant occurredAt) implements CaseEvent {}
public record CaseClosed(CaseId caseId, Instant occurredAt) implements CaseEvent {}

static String render(CaseEvent event) {
    return switch (event) {
        case CaseOpened(var caseId, var occurredAt) -> "opened " + caseId;
        case CaseEscalated(var caseId, var occurredAt) -> "escalated " + caseId;
        case CaseClosed(var caseId, var occurredAt) -> "closed " + caseId;
    };
}

Record component list menjadi bagian dari matching surface.
Mengubah component list bisa berdampak ke caller yang melakukan deconstruction.

public record CaseResponse(
    String id,
    String status,
    Instant updatedAt
) {}

Apakah nama component adalah nama field JSON?
Apakah rename component berarti breaking API?
Apakah timestamp format stabil?
Apakah enum dikirim sebagai name, code, atau object?
Apakah null field boleh muncul?
Apakah constructor validation compatible dengan deserializer?

ORM entity sering butuh identity lifecycle.
ORM sering memakai proxy/lazy loading.
ORM sering butuh no-arg constructor atau field mutation internal.
Record final dan transparan.
Record equality berbasis semua components.

public record CaseSummary(
    CaseId id,
    CaseStatus status,
    OfficerId assignee,
    Instant updatedAt
) {}

public record CaseId(String value) {
    public CaseId {
        Objects.requireNonNull(value, "value");
        if (value.isBlank()) {
            throw new IllegalArgumentException("CaseId must not be blank");
        }
    }
}

public record OfficerId(String value) {
    public OfficerId {
        Objects.requireNonNull(value, "value");
        if (value.isBlank()) {
            throw new IllegalArgumentException("OfficerId must not be blank");
        }
    }
}

void assign(CaseId caseId, OfficerId officerId) {}

CaseId caseId = new CaseId("C-1");
OfficerId officerId = new OfficerId("O-1");

assign(caseId, officerId); // benar
// assign(officerId, caseId); // compile error

public record EvidenceBundle(List<EvidenceId> evidenceIds) {}

public record EvidenceBundle(List<EvidenceId> evidenceIds) {
    public EvidenceBundle {
        evidenceIds = List.copyOf(evidenceIds);
    }
}

public record Case(CaseId id, CaseStatus status) {}

public record CreateCaseRequest(
    String a, String b, String c, String d, String e,
    String f, String g, String h, String i, String j
) {}

public record SubjectInfo(...) {}
public record CaseMetadata(...) {}
public record CreateCaseRequest(SubjectInfo subject, CaseMetadata metadata) {}

public record CaseView(boolean urgent, boolean confidential, boolean escalated, boolean closed) {}

public enum CaseVisibility { PUBLIC, CONFIDENTIAL, RESTRICTED }
public enum CaseLifecycleStatus { OPEN, ESCALATED, CLOSED }

public record PersonName(String firstName, String lastName, String fullName) {}

public record PersonName(String firstName, String lastName) {
    public String fullName() {
        return firstName + " " + lastName;
    }
}

class DateRangeTest {
    @Test
    void rejectsEndBeforeStart() {
        LocalDate start = LocalDate.of(2026, 1, 10);
        LocalDate end = LocalDate.of(2026, 1, 1);

        assertThrows(IllegalArgumentException.class, () -> new DateRange(start, end));
    }

    @Test
    void containsStartButNotEndExclusive() {
        DateRange range = new DateRange(
            LocalDate.of(2026, 1, 1),
            LocalDate.of(2026, 1, 10)
        );

        assertTrue(range.contains(LocalDate.of(2026, 1, 1)));
        assertFalse(range.contains(LocalDate.of(2026, 1, 10)));
    }
}

Null rejection.
Range validation.
Cross-component invariant.
Normalization.
Defensive copy.
Equality if component has tricky equals.
Serialization/deserialization if used as API DTO.

1. Apakah tipe ini benar-benar transparent data carrier?
2. Apakah equality berbasis semua components memang benar?
3. Apakah component list stabil sebagai kontrak?
4. Apakah semua nullable component disengaja?
5. Apakah mutable components sudah defensive copied?
6. Apakah constructor hanya menjaga invariant lokal?
7. Apakah component order aman dan tidak raw/ambiguous?
8. Apakah record dipakai sebagai entity padahal butuh lifecycle behavior?
9. Apakah toString aman dari PII/secret leakage?
10. Apakah record ini melewati serialization/API boundary?
11. Apakah rename/add/remove component punya migration plan?
12. Apakah value object satu component lebih baik daripada raw primitive?

public final class CaseDeadline {
    private final String caseId;
    private final LocalDate dueDate;
    private final boolean businessDayOnly;

    // constructor, getter, equals, hashCode, toString...
}

1. `caseId` jangan raw String; bungkus menjadi `CaseId` record.
2. `businessDayOnly` jangan boolean jika semantics lebih kaya.
3. Tambahkan invariant: dueDate tidak boleh null.
4. Tambahkan method `isOverdue(LocalDate today)`.
5. Jelaskan apakah equality berbasis semua components benar.

public record CaseId(String value) {
    public CaseId {
        Objects.requireNonNull(value, "value");
        if (value.isBlank()) throw new IllegalArgumentException("blank case id");
    }
}

public enum DeadlineCalendarPolicy {
    CALENDAR_DAY,
    BUSINESS_DAY_ONLY
}

public record CaseDeadline(
    CaseId caseId,
    LocalDate dueDate,
    DeadlineCalendarPolicy calendarPolicy
) {
    public CaseDeadline {
        Objects.requireNonNull(caseId, "caseId");
        Objects.requireNonNull(dueDate, "dueDate");
        Objects.requireNonNull(calendarPolicy, "calendarPolicy");
    }

    public boolean isOverdue(LocalDate today) {
        Objects.requireNonNull(today, "today");
        return today.isAfter(dueDate);
    }
}

nominal,
transparan,
final,
berbasis komponen,
shallow immutable,
dan equality-nya jelas.

Apakah state utama tipe ini memang kontrak publik yang transparan?
Apakah equality semua components adalah semantics yang benar?
Apakah tipe ini tidak membutuhkan lifecycle identity yang tersembunyi?