How to map multiple classes to one table in JPA? - spring-boot

Question

I know this is a frequently asked question, but I couldn't find any answers because I have 3 classes and I generally have problems to build the given structure:
type OrderItem = {
count: number,
price: number,
order: number,
subItems: {
count: number,
name: string,
price: number,
extraItems: {
count: number,
name: string,
price: number,
}
}
};
This is my try at doing it in Java with JPA:
Order.java
package de.gabriel.mcdonaldsproject.models;
import javax.persistence.*;
import java.io.Serializable;
import java.util.List;
#Entity
#Table(name = "orders", schema = "public")
public class Order implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "order_generator")
#SequenceGenerator(name = "order_generator", sequenceName = "order_seq")
private long id;
private List<Item> products; // <--------- 'Basic' attribute type should not be a container
public Order() {
}
public Order(List<Item> products) {
this.products = products;
}
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
public List<Item> getProducts() {
return products;
}
public void setProducts(List<Item> product) {
this.products = product;
}
}
Item.java
package de.gabriel.mcdonaldsproject.models;
import javax.persistence.*;
public class Item{
private double count;
private double price;
private double order;
private SubItems subItems;
public Item(){}
public Item(double count, double price, double order, SubItems subItems) {
this.count = count;
this.price = price;
this.order = order;
this.subItems = subItems;
}
public double getCount() {
return count;
}
public void setCount(double count) {
this.count = count;
}
public double getPrice() {
return price;
}
public void setPrice(double price) {
this.price = price;
}
public double getOrder() {
return order;
}
public void setOrder(double order) {
this.order = order;
}
public SubItems getSubItems() {
return subItems;
}
public void setSubItems(SubItems subItems) {
this.subItems = subItems;
}
}
SubItems.java
package de.gabriel.mcdonaldsproject.models;
import javax.persistence.*;
import java.util.List;
public class SubItems {
private double count;
private String name;
private double price;
private List<String> extraItems;
public SubItems(){}
public SubItems(double count, String name, double price, List<String> extraItems) {
this.count = count;
this.name = name;
this.price = price;
this.extraItems = extraItems;
}
public double getCount() {
return count;
}
public void setCount(double count) {
this.count = count;
}
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 List<String> getExtraItems() {
return extraItems;
}
public void setExtraItems(List<String> extraItems) {
this.extraItems = extraItems;
}
}
Does someone have an idea on how to rebuild this structure in Java with JPA so it also gets saved in the database?

Answer 1

If this object orderitem is not going to expand, I would suggest JSON string saving in the database.
OR you can do following mappings:
#OneToMany(mappedBy="order")
public Order(List<Item> products) {
this.products = products;
}
#OneToOne(cascade = CascadeType.ALL)
#JoinColumn(name = "subitem_id", referencedColumnName = "id")
private SubItems subItems;

Answer 2

Update the following information like this :
#Embeddable
public class Item {
// .....
#Embedded
private SubItems subItems;
//.......
}
#Embeddable
public class SubItems {
// .....
#ElementCollection
private List<String> extraItems;
//.......
}
#Entity
#Table(name = "orders", schema = "public")
public class Order implements Serializable {
//.....
#ElementCollection
private List<Item> products;
//.......
}