JPA/Hibernate Java 17+ Extras

This is a small library that simplifies usage of JPA/Hibernate. It adds:

1. Better support for entity manager injection using mixin-like inheritance
2. Better support for transactional code
3. Support for persisting lambdas
4. Junit 5 Persistence Tests
5. Schema Generation

1. Entity Manager injection

Just add WithSimplePersistenceUnit:

import io.github.flbulgarelli.jpa.extras.simple.WithSimplePersistenceUnit;

public class UserRepository implements WithSimplePersistenceUnit {

  public static UserRepository INSTANCE = new UserRepository();

  public void addUser(User user) {
    persist(user);
  }

  public User find(Long id) {
    return find(User.class, id);
  }
}

By using this mixin, you'll get access to an entityManager(), plus some helper methods that act as shortcuts to the corresponding EntityManager:

• persist. See EntityManager#persist
• merge. See EntityManager#merge
• remove. See EntityManager#remove
• find. See EntityManager#find
• createQuery. See EntityManager#createQuery

4. Persistence Tests

In order to test code that has access to persistence context, just add the SimplePersistenceTest mixin to your Junit 5 test classes:

import io.github.flbulgarelli.jpa.extras.test.SimplePersistenceTest;

public class ATest implements SimplePersistenceTest {
  @Test
  void aTestThatRequiresAPersistenceContext() {
    // ....
  }
}

By using this mixin, all your code is going to be run within a transaction. Also, you get access to an entityManager() and the EntityManagerOps helpers:

import io.github.flbulgarelli.jpa.extras.test.SimplePersistenceTest;

public class ATest implements SimplePersistenceTest {
  @Test
  void aTestThatRequiresAPersistenceContext() {
    User user = new User();
    persist(user);
    assertNotNull(user.getId());
  }
}

5. Schema Generation

JPA does not provide an easy way to generate the SQL schema. With this library, you can generate it by executing JpaSchemaExport.

• Usage: JpaSchemaExport [...options]

• Options:

  • -o,--output <arg>: Output file. Defaults to schema.sql.
  • -f,--format: If the output file should be formatted. Defaults to false.
  • -t,--target <arg>: Target persistence unit. Defaults to simple-persistence-unit.
  • -h,--help: Print this message.

If you are using IntelliJ, you can add a Run Configuration with the following parameters:

• Main class: io.github.flbulgarelli.jpa.extras.export.JpaSchemaExport
• Program arguments: -o schema.sql -f
• Modify Options -> Add Run Options-> Java -> Add provided dependencies with "provided" scope to classpath

Installation

jpa-extras is hosted in the Maven Central Repository. Simply add the following dependency into your pom.xml file:

    <dependency>
      <groupId>io.github.flbulgarelli</groupId>
      <artifactId>jpa-extras</artifactId>
      <version>1.0.0-rc1</version>
    </dependency>

Snapshots

Also, snapshots of the master branch are deployed automatically with each successful commit. Instead of Maven Central, use the Sonatype snapshots repository at:

<url>https://s01.oss.sonatype.org/content/repositories/snapshots</url>

You can add the repository in your pom.xml file:

  <repositories>
    <repository>
      <id>sonatype-snapshots</id>
      <url>https://s01.oss.sonatype.org/content/repositories/snapshots</url>
      <snapshots>
        <enabled>true</enabled>
      </snapshots>
    </repository>
  </repositories>