package com.example.demo.dto;
import java.time.LocalDateTime;
import java.util.List;
// Simple record
public record UserDTO(
Long id,
String name,
String email
) {}
// Record with validation
public record CreateUserRequest(
String name,
String email,
String password
) {
// Compact constructor for validation
public CreateUserRequest {
if (name == null || name.isBlank()) {
throw new IllegalArgumentException("Name cannot be blank");
}
if (email == null || !email.contains("@")) {
throw new IllegalArgumentException("Invalid email format");
}
if (password == null || password.length() < 8) {
throw new IllegalArgumentException("Password must be at least 8 characters");
}
}
}
// Record with computed fields
public record Money(double amount, String currency) {
public Money add(Money other) {
if (!currency.equals(other.currency)) {
throw new IllegalArgumentException("Currency mismatch");
}
return new Money(amount + other.amount, currency);
}
public String formatted() {
return String.format("%s %.2f", currency, amount);
}
}
// Record implementing interface
public interface Identifiable {
Long getId();
}
public record Post(
Long id,
Long userId,
String title,
String content,
LocalDateTime createdAt
) implements Identifiable {
@Override
public Long getId() {
return id;
}
public boolean isRecent() {
return createdAt.isAfter(LocalDateTime.now().minusDays(7));
}
}
// Nested records
public record Order(
Long id,
Customer customer,
List<LineItem> items,
Money total
) {
public record Customer(String name, String email) {}
public record LineItem(String product, int quantity, Money price) {}
}
// Record with static factory method
public record ApiResponse<T>(
boolean success,
T data,
String message,
int statusCode
) {
public static <T> ApiResponse<T> success(T data) {
return new ApiResponse<>(true, data, "Success", 200);
}
public static <T> ApiResponse<T> error(String message, int statusCode) {
return new ApiResponse<>(false, null, message, statusCode);
}
}
package com.example.demo.controller;
import com.example.demo.dto.*;
import org.springframework.web.bind.annotation.*;
@RestController
@RequestMapping("/api/users")
public class RecordController {
private final UserService userService;
public RecordController(UserService userService) {
this.userService = userService;
}
@PostMapping
public ApiResponse<UserDTO> createUser(@RequestBody CreateUserRequest request) {
try {
UserDTO user = userService.createUser(request);
return ApiResponse.success(user);
} catch (Exception e) {
return ApiResponse.error(e.getMessage(), 400);
}
}
@GetMapping("/{id}")
public ApiResponse<UserDTO> getUser(@PathVariable Long id) {
return userService.findById(id)
.map(ApiResponse::success)
.orElse(ApiResponse.error("User not found", 404));
}
}
