SpringBootStackApplication.java

package com.example;

import java.util.ArrayList;
import java.util.List;

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.OneToMany;

import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Component;

import com.fasterxml.jackson.annotation.JsonIdentityInfo;
import com.fasterxml.jackson.annotation.ObjectIdGenerators;

@SpringBootApplication
public class SpringBootStackApplication {

	public static void main(String[] args) {
		SpringApplication.run(SpringBootStackApplication.class, args);
	}

	@Bean
	CommandLineRunner commandLineRunner(VisitorRepository visitorRepository) {
		return (args) -> {
			Visitor visitor = new Visitor("007");
			VisitorCharacteristic visitorCharacteristicA = new VisitorCharacteristic("123", "456");
			VisitorCharacteristic visitorCharacteristicB = new VisitorCharacteristic("789", "000");

			visitor.addVisitorCharacteristic(visitorCharacteristicA);
			visitor.addVisitorCharacteristic(visitorCharacteristicB);
			visitorRepository.save(visitor);
		};
	}

}

@Component
interface VisitorRepository extends JpaRepository<Visitor, Long> {

}


@Entity
@JsonIdentityInfo(generator=ObjectIdGenerators.PropertyGenerator.class, property="id")
class Visitor {
	@Id
	@Column(name="visitor_revision_id")
	@GeneratedValue(strategy= GenerationType.IDENTITY)
	Long id;

	String visitorCode;

	@OneToMany(fetch = FetchType.EAGER, cascade = CascadeType.ALL, mappedBy = "visitor")
	List<VisitorCharacteristic> visitorCharacteristicList;

	public Visitor() {
	}

	public Visitor(String visitorCode) {
		this.visitorCode = visitorCode;
	}

	public void addVisitorCharacteristic(VisitorCharacteristic visitorCharacteristic) {
		if (visitorCharacteristicList == null) {
			visitorCharacteristicList = new ArrayList<>();
		}
		visitorCharacteristic.visitor = this;
		visitorCharacteristicList.add(visitorCharacteristic);
	}
}

@Entity
@JsonIdentityInfo(generator=ObjectIdGenerators.PropertyGenerator.class, property="id")
class VisitorCharacteristic {
	@Id
	@GeneratedValue(strategy=GenerationType.IDENTITY)
	Long id;

	@JoinColumn(name = "visitor_revision_id")
	@ManyToOne(optional = false) //fetch = FetchType.EAGER, cascade =  CascadeType.ALL)
	Visitor visitor;

	@Column(nullable = false)
	String attributeCode;

	@Column(nullable = false)
	String attributeValue;

	public VisitorCharacteristic() {
	}

	public VisitorCharacteristic(String attributeCode, String attributeValue) {
		this.attributeCode = attributeCode;
		this.attributeValue = attributeValue;
	}
}