Feature

• Fully integrated library with JPA (Hibernates) and QueryDsl
• Focus on business logic without worrying about Optimize join performance and DTO-entity mapping
• Finds the index of the Entity on itself and rearranges the predicates to create the optimal query.
• Find associations between entities on your own and perform the Join operation

Installation

1. Download deploy/* in repository
2. Update your build.gradle as following

repositories {
  // add maven 
  maven {
    url = uri("file:///absolute/path/to/deploy")
  }

  dependencies {
    // add dependency
    implementation 'org.sejong:JpajoinMaestro:0.0.1-SNAPSHOT'
  }
}

How to use

1. Add the @DTOMapping Annotation to your DTO.

There are two attributes to include domain: Defines from which @Entity Class the respective DTO Field is sourced. field: Specifies which Field from the @Entity Class corresponds to the respective DTO Field.

An example of how to use this is as follows:

package org.sejong.jpajoinmaestro.dto;

import lombok.Getter;
import lombok.Setter;
import org.sejong.jpajoinmaestro.core.annotations.DTOFieldMapping;
import org.sejong.jpajoinmaestro.domain.OrderDetail;
import org.sejong.jpajoinmaestro.domain.Orders;
import org.sejong.jpajoinmaestro.domain.Product;
import org.sejong.jpajoinmaestro.domain.User;

@Getter
@Setter
public class MyOrder {
    @DTOFieldMapping(domain= User.class, fieldName="username")
    private String username;

    @DTOFieldMapping(domain = Orders.class, fieldName = "status")
    private String status;

    @DTOFieldMapping(domain=Product.class, fieldName="productName")
    private String productName;

    @DTOFieldMapping(domain= OrderDetail.class, fieldName = "quantity")
    private Long quantity;

    @DTOFieldMapping(domain=Product.class, fieldName="price")
    private Long price;

    public MyOrder(){}
}

Note! Be sure to add a default constructor.

2. Add JPAQueryFactory to your service and use createJoinQuery.

If you want to add conditions, declare ClauseBuilder and pass it as a parameter to the createJoinQuery function.

An example of how to use this is as follows:

@Service
@RequiredArgsConstructor
public class ExampleService {
  private final JPAQueryFactory queryFactory;

  public List<MyOrder> getMyOrder() {
    ClauseBuilder pb = new ClauseBuilder()
      .where(new Equal().to(User.class, "id", 1))
      .andWhere(new Equal().to(Orders.class, "user_id", 1))
      .andWhere(new Equal().to(OrderDetail.class, "orders_id", 1));

    List<MyOrder> results = joinQueryBuilder.createJoinQuery(MyOrder.class, pb);

    return results;
  }
  
}

Note: The Class used in the ClauseBuilder example is a predefined Class with the @Entity Annotation.

Performance

Note: Jmeter was used with the number of threads set to 1. The performance metrics example above was measured based on a join of 3 tables.