Spark graphx moved to a new project due to a incompatibility of scala compiler

spring-boot-angular/src/main/java/com/baeldung/application/Application.java

@@ -0,0 +1,28 @@
+package com.baeldung.application;
+
+import com.baeldung.application.entities.User;
+import com.baeldung.application.repositories.UserRepository;
+import java.util.stream.Stream;
+import org.springframework.boot.CommandLineRunner;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.context.annotation.Bean;
+
+@SpringBootApplication
+public class Application {
+
+    public static void main(String[] args) {
+        SpringApplication.run(Application.class, args);
+    }
+
+    @Bean
+    CommandLineRunner init(UserRepository userRepository) {
+        return args -> {
+            Stream.of("John", "Julie", "Jennifer", "Helen", "Rachel").forEach(name -> {
+                User user = new User(name, name.toLowerCase() + "@domain.com");
+                userRepository.save(user);
+            });
+            userRepository.findAll().forEach(System.out::println);
+        };
+    }
+}

spring-boot-angular/src/main/java/com/baeldung/application/controllers/UserController.java

@@ -0,0 +1,31 @@
+package com.baeldung.application.controllers;
+
+import com.baeldung.application.entities.User;
+import com.baeldung.application.repositories.UserRepository;
+import java.util.List;
+import org.springframework.web.bind.annotation.CrossOrigin;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+@CrossOrigin(origins = "http://localhost:4200")
+public class UserController {
+
+    private final UserRepository userRepository;
+
+    public UserController(UserRepository userRepository) {
+        this.userRepository = userRepository;
+    }
+
+    @GetMapping("/users")
+    public List<User> getUsers() {
+        return (List<User>) userRepository.findAll();
+    }
+
+    @PostMapping("/users")
+    void addUser(@RequestBody User user) {
+        userRepository.save(user);
+    }
+}

spring-boot-angular/src/main/java/com/baeldung/application/entities/User.java

@@ -0,0 +1,43 @@
+package com.baeldung.application.entities;
+
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.GenerationType;
+import javax.persistence.Id;
+
+@Entity
+public class User {
+    
+    @Id
+    @GeneratedValue(strategy = GenerationType.AUTO)
+    private long id;
+    private final String name;
+    private final String email;
+    
+    public User() {
+        this.name = "";
+        this.email = "";
+    }
+    
+    public User(String name, String email) {
+        this.name = name;
+        this.email = email;
+    }
+
+    public long getId() {
+        return id;
+    }
+    
+    public String getName() {
+        return name;
+    }
+
+    public String getEmail() {
+        return email;
+    }
+    
+    @Override
+    public String toString() {
+        return "User{" + "id=" + id + ", name=" + name + ", email=" + email + '}';
+    }
+}

spring-boot-angular/src/main/java/com/baeldung/application/repositories/UserRepository.java

@@ -0,0 +1,9 @@
+package com.baeldung.application.repositories;
+
+import com.baeldung.application.entities.User;
+import org.springframework.data.repository.CrudRepository;
+import org.springframework.stereotype.Repository;
+import org.springframework.web.bind.annotation.CrossOrigin;
+
+@Repository
+public interface UserRepository extends CrudRepository<User, Long>{}

spring-boot-angular/src/main/java/com/baeldung/ecommerce/EcommerceApplication.java

@@ -0,0 +1,29 @@
+package com.baeldung.ecommerce;
+
+import com.baeldung.ecommerce.model.Product;
+import com.baeldung.ecommerce.service.ProductService;
+import org.springframework.boot.CommandLineRunner;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.context.annotation.Bean;
+
+@SpringBootApplication
+public class EcommerceApplication {
+
+    public static void main(String[] args) {
+        SpringApplication.run(EcommerceApplication.class, args);
+    }
+
+    @Bean
+    CommandLineRunner runner(ProductService productService) {
+        return args -> {
+            productService.save(new Product(1L, "TV Set", 300.00, "http://placehold.it/200x100"));
+            productService.save(new Product(2L, "Game Console", 200.00, "http://placehold.it/200x100"));
+            productService.save(new Product(3L, "Sofa", 100.00, "http://placehold.it/200x100"));
+            productService.save(new Product(4L, "Icecream", 5.00, "http://placehold.it/200x100"));
+            productService.save(new Product(5L, "Beer", 3.00, "http://placehold.it/200x100"));
+            productService.save(new Product(6L, "Phone", 500.00, "http://placehold.it/200x100"));
+            productService.save(new Product(7L, "Watch", 30.00, "http://placehold.it/200x100"));
+        };
+    }
+}

spring-boot-angular/src/main/java/com/baeldung/ecommerce/controller/OrderController.java

@@ -0,0 +1,99 @@
+package com.baeldung.ecommerce.controller;
+
+import com.baeldung.ecommerce.dto.OrderProductDto;
+import com.baeldung.ecommerce.exception.ResourceNotFoundException;
+import com.baeldung.ecommerce.model.Order;
+import com.baeldung.ecommerce.model.OrderProduct;
+import com.baeldung.ecommerce.model.OrderStatus;
+import com.baeldung.ecommerce.service.OrderProductService;
+import com.baeldung.ecommerce.service.OrderService;
+import com.baeldung.ecommerce.service.ProductService;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.util.CollectionUtils;
+import org.springframework.web.bind.annotation.*;
+import org.springframework.web.servlet.support.ServletUriComponentsBuilder;
+
+import javax.validation.constraints.NotNull;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
+import java.util.stream.Collectors;
+
+@RestController
+@RequestMapping("/api/orders")
+public class OrderController {
+
+    ProductService productService;
+    OrderService orderService;
+    OrderProductService orderProductService;
+
+    public OrderController(ProductService productService, OrderService orderService, OrderProductService orderProductService) {
+        this.productService = productService;
+        this.orderService = orderService;
+        this.orderProductService = orderProductService;
+    }
+
+    @GetMapping
+    @ResponseStatus(HttpStatus.OK)
+    public @NotNull Iterable<Order> list() {
+        return this.orderService.getAllOrders();
+    }
+
+    @PostMapping
+    public ResponseEntity<Order> create(@RequestBody OrderForm form) {
+        List<OrderProductDto> formDtos = form.getProductOrders();
+        validateProductsExistence(formDtos);
+        Order order = new Order();
+        order.setStatus(OrderStatus.PAID.name());
+        order = this.orderService.create(order);
+
+        List<OrderProduct> orderProducts = new ArrayList<>();
+        for (OrderProductDto dto : formDtos) {
+            orderProducts.add(orderProductService.create(new OrderProduct(order, productService.getProduct(dto
+              .getProduct()
+              .getId()), dto.getQuantity())));
+        }
+
+        order.setOrderProducts(orderProducts);
+
+        this.orderService.update(order);
+
+        String uri = ServletUriComponentsBuilder
+          .fromCurrentServletMapping()
+          .path("/orders/{id}")
+          .buildAndExpand(order.getId())
+          .toString();
+        HttpHeaders headers = new HttpHeaders();
+        headers.add("Location", uri);
+
+        return new ResponseEntity<>(order, headers, HttpStatus.CREATED);
+    }
+
+    private void validateProductsExistence(List<OrderProductDto> orderProducts) {
+        List<OrderProductDto> list = orderProducts
+          .stream()
+          .filter(op -> Objects.isNull(productService.getProduct(op
+            .getProduct()
+            .getId())))
+          .collect(Collectors.toList());
+
+        if (!CollectionUtils.isEmpty(list)) {
+            new ResourceNotFoundException("Product not found");
+        }
+    }
+
+    public static class OrderForm {
+
+        private List<OrderProductDto> productOrders;
+
+        public List<OrderProductDto> getProductOrders() {
+            return productOrders;
+        }
+
+        public void setProductOrders(List<OrderProductDto> productOrders) {
+            this.productOrders = productOrders;
+        }
+    }
+}

spring-boot-angular/src/main/java/com/baeldung/ecommerce/controller/ProductController.java

@@ -0,0 +1,25 @@
+package com.baeldung.ecommerce.controller;
+
+import com.baeldung.ecommerce.model.Product;
+import com.baeldung.ecommerce.service.ProductService;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+import javax.validation.constraints.NotNull;
+
+@RestController
+@RequestMapping("/api/products")
+public class ProductController {
+
+    private ProductService productService;
+
+    public ProductController(ProductService productService) {
+        this.productService = productService;
+    }
+
+    @GetMapping(value = { "", "/" })
+    public @NotNull Iterable<Product> getProducts() {
+        return productService.getAllProducts();
+    }
+}

spring-boot-angular/src/main/java/com/baeldung/ecommerce/dto/OrderProductDto.java

@@ -0,0 +1,25 @@
+package com.baeldung.ecommerce.dto;
+
+import com.baeldung.ecommerce.model.Product;
+
+public class OrderProductDto {
+
+    private Product product;
+    private Integer quantity;
+
+    public Product getProduct() {
+        return product;
+    }
+
+    public void setProduct(Product product) {
+        this.product = product;
+    }
+
+    public Integer getQuantity() {
+        return quantity;
+    }
+
+    public void setQuantity(Integer quantity) {
+        this.quantity = quantity;
+    }
+}

spring-boot-angular/src/main/java/com/baeldung/ecommerce/exception/ApiExceptionHandler.java

@@ -0,0 +1,81 @@
+package com.baeldung.ecommerce.exception;
+
+import com.fasterxml.jackson.annotation.JsonInclude;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.ExceptionHandler;
+import org.springframework.web.bind.annotation.RestControllerAdvice;
+
+import javax.validation.ConstraintViolation;
+import javax.validation.ConstraintViolationException;
+import java.util.ArrayList;
+import java.util.List;
+
+@RestControllerAdvice
+public class ApiExceptionHandler {
+
+    @SuppressWarnings("rawtypes")
+    @ExceptionHandler(ConstraintViolationException.class)
+    public ResponseEntity<ErrorResponse> handle(ConstraintViolationException e) {
+        ErrorResponse errors = new ErrorResponse();
+        for (ConstraintViolation violation : e.getConstraintViolations()) {
+            ErrorItem error = new ErrorItem();
+            error.setCode(violation.getMessageTemplate());
+            error.setMessage(violation.getMessage());
+            errors.addError(error);
+        }
+
+        return new ResponseEntity<>(errors, HttpStatus.BAD_REQUEST);
+    }
+
+    @SuppressWarnings("rawtypes")
+    @ExceptionHandler(ResourceNotFoundException.class)
+    public ResponseEntity<ErrorItem> handle(ResourceNotFoundException e) {
+        ErrorItem error = new ErrorItem();
+        error.setMessage(e.getMessage());
+
+        return new ResponseEntity<>(error, HttpStatus.NOT_FOUND);
+    }
+
+    public static class ErrorItem {
+
+        @JsonInclude(JsonInclude.Include.NON_NULL) private String code;
+
+        private String message;
+
+        public String getCode() {
+            return code;
+        }
+
+        public void setCode(String code) {
+            this.code = code;
+        }
+
+        public String getMessage() {
+            return message;
+        }
+
+        public void setMessage(String message) {
+            this.message = message;
+        }
+
+    }
+
+    public static class ErrorResponse {
+
+        private List<ErrorItem> errors = new ArrayList<>();
+
+        public List<ErrorItem> getErrors() {
+            return errors;
+        }
+
+        public void setErrors(List<ErrorItem> errors) {
+            this.errors = errors;
+        }
+
+        public void addError(ErrorItem error) {
+            this.errors.add(error);
+        }
+
+    }
+}

spring-boot-angular/src/main/java/com/baeldung/ecommerce/exception/ResourceNotFoundException.java

@@ -0,0 +1,22 @@
+package com.baeldung.ecommerce.exception;
+
+public class ResourceNotFoundException extends RuntimeException {
+
+    private static final long serialVersionUID = 5861310537366287163L;
+
+    public ResourceNotFoundException() {
+        super();
+    }
+
+    public ResourceNotFoundException(final String message, final Throwable cause) {
+        super(message, cause);
+    }
+
+    public ResourceNotFoundException(final String message) {
+        super(message);
+    }
+
+    public ResourceNotFoundException(final Throwable cause) {
+        super(cause);
+    }
+}

spring-boot-angular/src/main/java/com/baeldung/ecommerce/model/Order.java

@@ -0,0 +1,78 @@
+package com.baeldung.ecommerce.model;
+
+import com.fasterxml.jackson.annotation.JsonFormat;
+import com.fasterxml.jackson.annotation.JsonIdentityInfo;
+import com.fasterxml.jackson.annotation.JsonManagedReference;
+import com.fasterxml.jackson.annotation.ObjectIdGenerators;
+
+import javax.persistence.*;
+import javax.validation.Valid;
+import java.time.LocalDate;
+import java.util.ArrayList;
+import java.util.List;
+
+@Entity
+@Table(name = "orders")
+@JsonIdentityInfo(generator=ObjectIdGenerators.PropertyGenerator.class, property="orderProducts")
+public class Order {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+    @JsonFormat(pattern = "dd/MM/yyyy") private LocalDate dateCreated;
+
+    private String status;
+
+    @OneToMany(mappedBy = "pk.order")
+    @Valid
+    private List<OrderProduct> orderProducts = new ArrayList<>();
+
+    @Transient
+    public Double getTotalOrderPrice() {
+        double sum = 0D;
+        List<OrderProduct> orderProducts = getOrderProducts();
+        for (OrderProduct op : orderProducts) {
+            sum += op.getTotalPrice();
+        }
+
+        return sum;
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public LocalDate getDateCreated() {
+        return dateCreated;
+    }
+
+    public void setDateCreated(LocalDate dateCreated) {
+        this.dateCreated = dateCreated;
+    }
+
+    public String getStatus() {
+        return status;
+    }
+
+    public void setStatus(String status) {
+        this.status = status;
+    }
+
+    public List<OrderProduct> getOrderProducts() {
+        return orderProducts;
+    }
+
+    public void setOrderProducts(List<OrderProduct> orderProducts) {
+        this.orderProducts = orderProducts;
+    }
+
+    @Transient
+    public int getNumberOfProducts() {
+        return this.orderProducts.size();
+    }
+}

spring-boot-angular/src/main/java/com/baeldung/ecommerce/model/OrderProduct.java

@@ -0,0 +1,87 @@
+package com.baeldung.ecommerce.model;
+
+import com.fasterxml.jackson.annotation.JsonIgnore;
+
+import javax.persistence.Column;
+import javax.persistence.EmbeddedId;
+import javax.persistence.Entity;
+import javax.persistence.Transient;
+
+@Entity
+public class OrderProduct {
+
+    @EmbeddedId
+    @JsonIgnore
+    private OrderProductPK pk;
+
+    @Column(nullable = false) private Integer quantity;
+
+    public OrderProduct() {
+        super();
+    }
+
+    public OrderProduct(Order order, Product product, Integer quantity) {
+        pk = new OrderProductPK();
+        pk.setOrder(order);
+        pk.setProduct(product);
+        this.quantity = quantity;
+    }
+
+    @Transient
+    public Product getProduct() {
+        return this.pk.getProduct();
+    }
+
+    @Transient
+    public Double getTotalPrice() {
+        return getProduct().getPrice() * getQuantity();
+    }
+
+    public OrderProductPK getPk() {
+        return pk;
+    }
+
+    public void setPk(OrderProductPK pk) {
+        this.pk = pk;
+    }
+
+    public Integer getQuantity() {
+        return quantity;
+    }
+
+    public void setQuantity(Integer quantity) {
+        this.quantity = quantity;
+    }
+
+    @Override
+    public int hashCode() {
+        final int prime = 31;
+        int result = 1;
+        result = prime * result + ((pk == null) ? 0 : pk.hashCode());
+
+        return result;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (obj == null) {
+            return false;
+        }
+        if (getClass() != obj.getClass()) {
+            return false;
+        }
+        OrderProduct other = (OrderProduct) obj;
+        if (pk == null) {
+            if (other.pk != null) {
+                return false;
+            }
+        } else if (!pk.equals(other.pk)) {
+            return false;
+        }
+
+        return true;
+    }
+}

spring-boot-angular/src/main/java/com/baeldung/ecommerce/model/OrderProductPK.java

@@ -0,0 +1,91 @@
+package com.baeldung.ecommerce.model;
+
+import com.fasterxml.jackson.annotation.JsonIdentityInfo;
+import com.fasterxml.jackson.annotation.ObjectIdGenerators;
+
+import javax.persistence.Embeddable;
+import javax.persistence.FetchType;
+import javax.persistence.JoinColumn;
+import javax.persistence.ManyToOne;
+import java.io.Serializable;
+
+@Embeddable
+@JsonIdentityInfo(generator = ObjectIdGenerators.PropertyGenerator.class, property = "order")
+public class OrderProductPK implements Serializable {
+
+    private static final long serialVersionUID = 476151177562655457L;
+
+    @ManyToOne(optional = false, fetch = FetchType.LAZY)
+    @JoinColumn(name = "order_id")
+    private Order order;
+
+    @ManyToOne(optional = false, fetch = FetchType.LAZY)
+    @JoinColumn(name = "product_id")
+    private Product product;
+
+    public Order getOrder() {
+        return order;
+    }
+
+    public void setOrder(Order order) {
+        this.order = order;
+    }
+
+    public Product getProduct() {
+        return product;
+    }
+
+    public void setProduct(Product product) {
+        this.product = product;
+    }
+
+    @Override
+    public int hashCode() {
+        final int prime = 31;
+        int result = 1;
+
+        result = prime * result + ((order.getId() == null)
+          ? 0
+          : order
+            .getId()
+            .hashCode());
+        result = prime * result + ((product.getId() == null)
+          ? 0
+          : product
+            .getId()
+            .hashCode());
+
+        return result;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (obj == null) {
+            return false;
+        }
+        if (getClass() != obj.getClass()) {
+            return false;
+        }
+        OrderProductPK other = (OrderProductPK) obj;
+        if (order == null) {
+            if (other.order != null) {
+                return false;
+            }
+        } else if (!order.equals(other.order)) {
+            return false;
+        }
+
+        if (product == null) {
+            if (other.product != null) {
+                return false;
+            }
+        } else if (!product.equals(other.product)) {
+            return false;
+        }
+
+        return true;
+    }
+}

spring-boot-angular/src/main/java/com/baeldung/ecommerce/model/OrderStatus.java

@@ -0,0 +1,5 @@
+package com.baeldung.ecommerce.model;
+
+public enum OrderStatus {
+    PAID
+}

spring-boot-angular/src/main/java/com/baeldung/ecommerce/model/Product.java

@@ -0,0 +1,62 @@
+package com.baeldung.ecommerce.model;
+
+import javax.persistence.*;
+import javax.validation.constraints.NotNull;
+
+@Entity
+public class Product {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+    @NotNull(message = "Product name is required.")
+    @Basic(optional = false)
+    private String name;
+
+    private Double price;
+
+    private String pictureUrl;
+
+    public Product(Long id, @NotNull(message = "Product name is required.") String name, Double price, String pictureUrl) {
+        this.id = id;
+        this.name = name;
+        this.price = price;
+        this.pictureUrl = pictureUrl;
+    }
+
+    public Product() {
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public Double getPrice() {
+        return price;
+    }
+
+    public void setPrice(Double price) {
+        this.price = price;
+    }
+
+    public String getPictureUrl() {
+        return pictureUrl;
+    }
+
+    public void setPictureUrl(String pictureUrl) {
+        this.pictureUrl = pictureUrl;
+    }
+}

spring-boot-angular/src/main/java/com/baeldung/ecommerce/repository/OrderProductRepository.java

@@ -0,0 +1,8 @@
+package com.baeldung.ecommerce.repository;
+
+import com.baeldung.ecommerce.model.OrderProduct;
+import com.baeldung.ecommerce.model.OrderProductPK;
+import org.springframework.data.repository.CrudRepository;
+
+public interface OrderProductRepository extends CrudRepository<OrderProduct, OrderProductPK> {
+}

spring-boot-angular/src/main/java/com/baeldung/ecommerce/repository/OrderRepository.java

@@ -0,0 +1,7 @@
+package com.baeldung.ecommerce.repository;
+
+import com.baeldung.ecommerce.model.Order;
+import org.springframework.data.repository.CrudRepository;
+
+public interface OrderRepository extends CrudRepository<Order, Long> {
+}

spring-boot-angular/src/main/java/com/baeldung/ecommerce/repository/ProductRepository.java

@@ -0,0 +1,7 @@
+package com.baeldung.ecommerce.repository;
+
+import com.baeldung.ecommerce.model.Product;
+import org.springframework.data.repository.CrudRepository;
+
+public interface ProductRepository extends CrudRepository<Product, Long> {
+}

spring-boot-angular/src/main/java/com/baeldung/ecommerce/service/OrderProductService.java

@@ -0,0 +1,13 @@
+package com.baeldung.ecommerce.service;
+
+import com.baeldung.ecommerce.model.OrderProduct;
+import org.springframework.validation.annotation.Validated;
+
+import javax.validation.Valid;
+import javax.validation.constraints.NotNull;
+
+@Validated
+public interface OrderProductService {
+
+    OrderProduct create(@NotNull(message = "The products for order cannot be null.") @Valid OrderProduct orderProduct);
+}

spring-boot-angular/src/main/java/com/baeldung/ecommerce/service/OrderProductServiceImpl.java

@@ -0,0 +1,22 @@
+package com.baeldung.ecommerce.service;
+
+import com.baeldung.ecommerce.model.OrderProduct;
+import com.baeldung.ecommerce.repository.OrderProductRepository;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+@Service
+@Transactional
+public class OrderProductServiceImpl implements OrderProductService {
+
+    private OrderProductRepository orderProductRepository;
+
+    public OrderProductServiceImpl(OrderProductRepository orderProductRepository) {
+        this.orderProductRepository = orderProductRepository;
+    }
+
+    @Override
+    public OrderProduct create(OrderProduct orderProduct) {
+        return this.orderProductRepository.save(orderProduct);
+    }
+}

spring-boot-angular/src/main/java/com/baeldung/ecommerce/service/OrderService.java

@@ -0,0 +1,17 @@
+package com.baeldung.ecommerce.service;
+
+import com.baeldung.ecommerce.model.Order;
+import org.springframework.validation.annotation.Validated;
+
+import javax.validation.Valid;
+import javax.validation.constraints.NotNull;
+
+@Validated
+public interface OrderService {
+
+    @NotNull Iterable<Order> getAllOrders();
+
+    Order create(@NotNull(message = "The order cannot be null.") @Valid Order order);
+
+    void update(@NotNull(message = "The order cannot be null.") @Valid Order order);
+}

spring-boot-angular/src/main/java/com/baeldung/ecommerce/service/OrderServiceImpl.java

@@ -0,0 +1,36 @@
+package com.baeldung.ecommerce.service;
+
+import com.baeldung.ecommerce.model.Order;
+import com.baeldung.ecommerce.repository.OrderRepository;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+import java.time.LocalDate;
+
+@Service
+@Transactional
+public class OrderServiceImpl implements OrderService {
+
+    private OrderRepository orderRepository;
+
+    public OrderServiceImpl(OrderRepository orderRepository) {
+        this.orderRepository = orderRepository;
+    }
+
+    @Override
+    public Iterable<Order> getAllOrders() {
+        return this.orderRepository.findAll();
+    }
+
+    @Override
+    public Order create(Order order) {
+        order.setDateCreated(LocalDate.now());
+
+        return this.orderRepository.save(order);
+    }
+
+    @Override
+    public void update(Order order) {
+        this.orderRepository.save(order);
+    }
+}

spring-boot-angular/src/main/java/com/baeldung/ecommerce/service/ProductService.java

@@ -0,0 +1,17 @@
+package com.baeldung.ecommerce.service;
+
+import com.baeldung.ecommerce.model.Product;
+import org.springframework.validation.annotation.Validated;
+
+import javax.validation.constraints.Min;
+import javax.validation.constraints.NotNull;
+
+@Validated
+public interface ProductService {
+
+    @NotNull Iterable<Product> getAllProducts();
+
+    Product getProduct(@Min(value = 1L, message = "Invalid product ID.") long id);
+
+    Product save(Product product);
+}

spring-boot-angular/src/main/java/com/baeldung/ecommerce/service/ProductServiceImpl.java

@@ -0,0 +1,35 @@
+package com.baeldung.ecommerce.service;
+
+import com.baeldung.ecommerce.exception.ResourceNotFoundException;
+import com.baeldung.ecommerce.model.Product;
+import com.baeldung.ecommerce.repository.ProductRepository;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+@Service
+@Transactional
+public class ProductServiceImpl implements ProductService {
+
+    private ProductRepository productRepository;
+
+    public ProductServiceImpl(ProductRepository productRepository) {
+        this.productRepository = productRepository;
+    }
+
+    @Override
+    public Iterable<Product> getAllProducts() {
+        return productRepository.findAll();
+    }
+
+    @Override
+    public Product getProduct(long id) {
+        return productRepository
+          .findById(id)
+          .orElseThrow(() -> new ResourceNotFoundException("Product not found"));
+    }
+
+    @Override
+    public Product save(Product product) {
+        return productRepository.save(product);
+    }
+}