Kotlin JDSL is DSL for JPA Criteria API without generated metamodel and reflection. It helps you write a JPA query like writing an SQL statement.
This is a temporary solution, and for those who just want a cool functional library bypassing Hibernate in Kotlin, orig. the library does not support Hibernate 6 and Jakarta, if your Hibernate version is less than version 6, checkout the original repositories.
There are several libraries in the easy way to use JPA. However, those libraries have to use APT. If you use APT, there is a problem that you have to compile again when the name or type of entity field is changed. So, in order not to use APT, we created this library using the KProperty created by the kotlin compiler.
Added support for Hibernate 6, Jakarta (JPA 3.0) and java 11 compiler target. Removed Spring, Hibernate Reactive because modules don't support Hibernate 6.
- Download here: Release Page
- Then create ./lib folder where
pom.xmllocated and move jar's to there. - Add code below to
pom.xmlor tou can google how add local libraries to gradle, or add in Project Settings (Intellij Idea))
Add Hibernate Kotlin JDSL and Hibernate to dependencies
<dependency> <!-- JDSL CORE WITH JAKRATA -->
<groupId>com.linecorp.kotlin-jdsl</groupId>
<artifactId>kotlin-jdsl-core</artifactId>
<scope>system</scope>
<systemPath>${basedir}/lib/kotlin-jdsl-core-2.0.4.min-jakarta.jar</systemPath>
<version>2.0.4.min-jakarta</version>
</dependency>
<dependency> <!-- JDSL QUERY WITH JAKRATA -->
<groupId>com.linecorp.kotlin-jdsl</groupId>
<artifactId>kotlin-jdsl-query</artifactId>
<scope>system</scope>
<systemPath>${basedir}/lib/kotlin-jdsl-query-2.0.4.min-jakarta.jar</systemPath>
<version>2.0.4.min-jakarta</version>
</dependency>
<dependency> <!-- HIBERNATE JDSL WITH JAKRATA -->
<groupId>com.linecorp.kotlin-jdsl</groupId>
<artifactId>hibernate-kotlin-jdsl</artifactId>
<scope>system</scope>
<systemPath>${basedir}/lib/hibernate-kotlin-jdsl-2.0.4.min-jakarta.jar</systemPath>
<version>2.0.4.min-jakarta</version>
</dependency>Add Eclipselink Kotlin JDSL and Eclipselink to dependencies
<dependency> <!-- JDSL CORE WITH JAKRATA -->
<groupId>com.linecorp.kotlin-jdsl</groupId>
<artifactId>kotlin-jdsl-core</artifactId>
<scope>system</scope>
<systemPath>${basedir}/lib/kotlin-jdsl-core-2.0.4.min-jakarta.jar</systemPath>
<version>2.0.4.min-jakarta</version>
</dependency>
<dependency> <!-- JDSL QUERY WITH JAKRATA -->
<groupId>com.linecorp.kotlin-jdsl</groupId>
<artifactId>kotlin-jdsl-query</artifactId>
<scope>system</scope>
<systemPath>${basedir}/lib/kotlin-jdsl-query-2.0.4.min-jakarta.jar</systemPath>
<version>2.0.4.min-jakarta</version>
</dependency>
<dependency> <!-- ECLIPSELINK JDSL WITH JAKRATA -->
<groupId>com.linecorp.kotlin-jdsl</groupId>
<artifactId>eclipselink-kotlin-jdsl</artifactId>
<scope>system</scope>
<systemPath>${basedir}/lib/eclipselink-kotlin-jdsl-2.0.4.min-jakarta</systemPath>
<version>2.0.4.min-jakarta</version>
</dependency>Create QueryFactory using EntityManager
val queryFactory: QueryFactory = QueryFactoryImpl(
criteriaQueryCreator = CriteriaQueryCreatorImpl(entityManager),
subqueryCreator = SubqueryCreatorImpl()
)Query using it
queryFactory.listQuery<Entity> {
select(entity(Book::class))
from(entity(Book::class))
where(column(Book::id).equal(1000))
}Not supported due Hibernate 6 not supported with Spring & Reactive, use original JPA 2.0 repo.
You can easily write query using Entity associations.
If you want to return the DTO, use the DTO as the return type.
QueryFactory allows you to create JPA queries using DSL just like SQL queries.
val books: List<Book> = queryFactory.listQuery {
select(entity(Book::class))
from(entity(Book::class))
where(column(Book::author).equal("Shakespeare"))
}If you want to select the DTO, select columns in the order of constructor parameters.
data class Row(
val author: String,
val count: Long,
)
val books: List<Row> = queryFactory.listQuery {
select(listOf(column(Book::author), count(column(Book::id))))
from(entity(Book::class))
groupBy(column(Book::author))
}data class Row(
val author: String,
val count: Long,
)
val books: List<Row> = queryFactory.listQuery {
selectMulti(column(Book::author), count(column(Book::id)))
from(entity(Book::class))
groupBy(column(Book::author))
}Users can perform bulk update/delete through update/delete query.
- kotlin-jdsl's update/delete does not require from clause. Type T given as generic handles from automatically.
- According to the JPA specification, update/delete does not support join, fetch, group by, order by, limit.
- If you want to use an association mapping as a where condition, you must use associate.
val query: Query = queryFactory.updateQuery<Order> {
where(col(Order::purchaserId).`in`(1000, 2000))
setParams(col(Order::purchaserId) to 3000)
}
val updatedRowsCount: Int = query.executeUpdate()
val deleteQuery: Query = queryFactory.deleteQuery<Order> {
where(col(Order::purchaserId).`in`(1000, 2000))
}
val deletedRowsCount: Int = deleteQuery.executeUpdate()Kotlin JDSL supports various expressions.
val max = max(column(Book::price))
val count = count(column(Book::price))
val greatest = greatest(column(Book::createdAt))val case = case(
`when`(column(Book::name).like("A%")).then(literal(1)),
`when`(column(Book::name).like("B%")).then(literal(2)),
// ...
`else` = literal(999)
)val authorIds = queryFactory.subquery<Long> {
select(column(Book::authorId))
from(entity(Book::class))
// ...
}
val authors: List<Author> = queryFactory.listQuery {
// ...
where(column(Author::id).`in`(authorIds))
}Kotlin JDSL supports various predicates.
val condition = and(
column(Book::author).equal("Shakespeare"),
column(Book::price).lessThanOrEqualTo(100.toBigDecimal()),
column(Book::status).`in`(SALE, OUT_OF_STOCK),
column(Book::createdAt).between(Time.of("2001-01-01"), Time.of("2010-12-31")),
)val books = queryFactory.listQuery<Book> {
select(entity(Book::class))
from(entity(Book::class))
join(Book::author) //Default is `JoinType.INNER`
join(Book::publisher, JoinType.LEFT)
join(Book::seller, JoinType.RIGHT)
// ...
}val books = queryFactory.listQuery<Book> {
select(entity(Book::class))
from(entity(Book::class))
fetch(Book::author)
// ...
}If join and fetch are used together for the same entity, only fetch is applied.
val books = queryFactory.listQuery<Book> {
select(entity(Book::class))
from(entity(Book::class))
join(Book::author) // Join is ignored
fetch(Book::author) // Only fetch is applied
// ...
}val books = queryFactory.listQuery<Book> {
select(entity(Book::class))
from(entity(Book::class))
join(entity(Author::class), on(column(Book::authorId).equal(column(Author::id))))
// ...
}There may be models with the two associations of same type. In this case, separate the Entity using alias.
val orders = queryFactory.listQuery<Order> {
select(entity(Order::class))
from(entity(Order::class))
join(entity(Order::class), entity(Address::class, alias = "shippingAddress", on(Order::shippingAddress)))
join(entity(Order::class), entity(Address::class, alias = "receiverAddress", on(Order::receiverAddress)))
// ...
}associate behaves similarly to join, and operates exactly the same as join in select, and since Join cannot be used in update/delete, use associate to associate the relationship with other internally mapped objects (ex: @Embedded) You can build it and run the query.
val query = queryFactory.selectQuery<String> {
select(col(Address::zipCode))
from(entity(OrderAddress::class))
associate(OrderAddress::class, Address::class, on(OrderAddress::address))
}
val updatedRowCount = queryFactory.updateQuery<OrderAddress> {
where(col(OrderAddress::id).equal(address1.id))
associate(OrderAddress::class, Address::class, on(OrderAddress::address))
set(col(Address::zipCode), "test")
set(col(Address::baseAddress), "base")
}.executeUpdate()
val deletedRowCount = queryFactory.deleteQuery<OrderAddress> {
where(col(OrderAddress::id).equal(address1.id))
associate(OrderAddress::class, Address::class, on(OrderAddress::address))
}.executeUpdate()There may be situations where you need to downcast when using an Entity of an inheritance structure. In that case, you can use the code like below.
val employees = queryFactory.listQuery<Employee> {
selectDistinct(entity(Employee::class))
from(entity(Employee::class))
treat<Employee, PartTimeEmployee>()
where(
col(PartTimeEmployee::weeklySalary).lessThan(1000.toBigDecimal()),
)
}If you are downcasting from the root entity (Project Entity in this case) that contains an entity with inheritance structure, you can do it as follows.
val projects = queryFactory.listQuery<Project> {
selectDistinct(entity(Project::class))
from(entity(Project::class))
treat<Employee, FullTimeEmployee>(col(Project::employees))
where(
col(FullTimeEmployee::annualSalary).greaterThan(100000.toBigDecimal())
)
}For Hibernate, the issue at issue is currently unresolved and an additional inner(left) join is added to make the result It may come out as a duplicate. So you should always apply distinct to select above like examples
If you are using Hibernate and want to fetch downcasting entities, the query cannot be executed normally. That is, the example below will result in a runtime error because of this issue.
val sub = queryFactory.subquery<Long> {
select(col(Project::id))
from(entity(Project::class))
treat<Employee, FullTimeEmployee>(col(Project::employees))
treat<Employee, PartTimeEmployee>(col(Project::employees))
where(
or(
col(FullTimeEmployee::annualSalary).greaterThan(100000.toBigDecimal()),
col(PartTimeEmployee::weeklySalary).greaterThan(1000.toBigDecimal()),
)
)
}
val projects = queryFactory.listQuery<Project> {
val project = Project::class.alias("dedupeProject")
selectDistinct(project)
from(project)
val supervisor = Employee::class.alias("super")
val partTimeSuper = PartTimeEmployee::class.alias("partSuper")
// If you are using Hibernate and want to fetch downcasting entities, the query cannot be executed normally. That is, the example below will result in a runtime error.
fetch(project, supervisor, on(Project::supervisor))
treat(ColumnSpec<PartTimeEmployee>(project, Project::supervisor.name), supervisor, partTimeSuper)
where(
and(
col(project, Project::id).`in`(sub),
col(partTimeSuper, PartTimeEmployee::weeklySalary).equal(900.toBigDecimal()),
)
)
}If you want to use downcasting entity in select clause, Eclipselink does not support that function. An example is as follows.
val employees = queryFactory.listQuery<FullTimeEmployee> {
val project: EntitySpec<Project> = Project::class.alias("project")
val fullTimeEmployee = FullTimeEmployee::class.alias("fe")
val employee = Employee::class.alias("e")
selectDistinct(fullTimeEmployee)
from(project)
treat(ColumnSpec<FullTimeEmployee>(project, Project::employees.name), employee, fullTimeEmployee)
where(
ColumnSpec<BigDecimal>(fullTimeEmployee, FullTimeEmployee::annualSalary.name)
.greaterThan(100000.toBigDecimal())
)
}
The Entity structure corresponds to the following structure.
@Inheritance(strategy = InheritanceType.SINGLE_TABLE)
@Entity
@Table(name = "employee")
@DiscriminatorColumn(name = "EMP_TYPE")
class Employee(
@Id
@GeneratedValue
val id: Long,
val name: String
) {
override fun equals(other: Any?) = Objects.equals(id, (other as? Employee)?.id)
override fun hashCode() = Objects.hashCode(id)
}
@Entity
@Table(name = "fulltime_employee")
@DiscriminatorValue("F")
class FullTimeEmployee(
val annualSalary: BigDecimal,
override val id: Long,
override val name: String
) : Employee(id, name) {
override fun equals(other: Any?) = Objects.equals(id, (other as? FullTimeEmployee)?.id)
override fun hashCode() = Objects.hashCode(id)
}
@Entity
@Table(name = "parttime_employee")
@DiscriminatorValue("P")
class PartTimeEmployee(
val weeklySalary: BigDecimal,
override val id: Long,
override val name: String
) : Employee(id, name) {
override fun equals(other: Any?) = Objects.equals(id, (other as? PartTimeEmployee)?.id)
override fun hashCode() = Objects.hashCode(id)
}
@Entity
@Table(name = "contract_employee")
@DiscriminatorValue("C")
class ContractEmployee(
val hourlyRate: BigDecimal,
override val id: Long,
override val name: String
) : Employee(id, name) {
override fun equals(other: Any?) = Objects.equals(id, (other as? ContractEmployee)?.id)
override fun hashCode() = Objects.hashCode(id)
}
@Entity
@Table(name = "project")
class Project(
@Id
@GeneratedValue
val id: Long = 0,
val name: String,
@OneToMany(cascade = [CascadeType.ALL])
val employees: List<Employee>,
@OneToOne(cascade = [CascadeType.ALL], optional = false, fetch = FetchType.LAZY)
val supervisor: Employee
) {
override fun equals(other: Any?) = Objects.equals(id, (other as? Project)?.id)
override fun hashCode() = Objects.hashCode(id)
}
Kotlin's property reference provides KProperty interface. KProperty is created in java file at kotlin compile time. Since KProperty has the name of property, we can use it to write the expression of the Critical API.
If you type the JPA query as below,
queryFactory.listQuery<Book> {
select(entity(Book::class))
from(entity(Book::class))
where(column(Book::name).equal("Hamlet").and(column(Book::author).equal("Shakespeare")))
}Kotlin compiler creates PropertyReference.
final class ClassKt$books$1 extends PropertyReference1Impl {
public static final KProperty1 INSTANCE = new ClassKt$books$1();
books$1() {
super(Book.class, "name", "getName()Ljava/lang/String;", 0);
}
@Nullable
public Object get(@Nullable Object receiver) {
return ((Book) receiver).getName();
}
}
final class ClassKt$books$2 extends PropertyReference1Impl {
public static final KProperty1 INSTANCE = new ClassKt$books$2();
ClassKt$books$2() {
super(Book.class, "author", "getAuthor()Ljava/lang/String;", 0);
}
@Nullable
public Object get(@Nullable Object receiver) {
return ((Book) receiver).getAuthor();
}
}If you have any questions, please make Issues. And PR is always welcome.
Are you ready to join us? - https://careers.linecorp.com/ko/jobs/862
See CONTRIBUTING. If you believe you have discovered a vulnerability or have an issue related to security, please contact the maintainer directly or send us an email before sending a pull request.
Copyright 2021 LINE Corporation
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
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Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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