README-custom.md

📚 Spring Data DynamoDB Examples - 📕 Custom repository methods

This example shows how to use custom methods as part of Spring Data repository interfaces to implement custom logic.

Further explanation can be found

• as also the code

📜 Code sample

The repository interface is extend by an additional interface. It's implementation is found by the Impl suffix in the same package. Spring Data itself takes care of weaving in the implementation at runtime:

public interface UserRepository extends CrudRepository<User, Long>, CustomUserRepositoryMethods { }


public interface CustomUserRepositoryMethods {
    User calculateAge(User user);
}


public class CustomUserRepositoryMethodsImpl implements CustomUserRepositoryMethods {

    @Override
    public User calculateAge(User user) {
        /* custom code */
    }
}



// Regular method of the repository interface
User user = userRepository.findOne(id);
// Custom method available via the interface, too
userRepository.calculateAge(user);

📝 How to prepare:

• Update src/main/resources/application.properties

Key	Sample value	Description
amazon.aws.accesskey	N/A	AWS accesskey for DynamoDB
amazon.aws.secretkey	N/A	AWS secretkey for DynamoDB

▶️ How to run:

mvn compile exec:java@custom

📃 Output should look like:

2018-07-02 00:29:46.360  INFO 13591 --- [lication.main()] c.g.d.s.custom.Application               : Table USER found
2018-07-02 00:29:46.438  INFO 13591 --- [lication.main()] c.g.d.s.custom.Application               : Created user: User{id=084941a8-6d1a-41d6-94ee-4412b8ca6d72, firstname='Sebastian', lastname='Mueller', birthday=1970-01-17T22:29:31.154Z, age=0}
2018-07-02 00:29:46.479  INFO 13591 --- [lication.main()] c.g.d.s.custom.Application               : Called custom method: User{id=084941a8-6d1a-41d6-94ee-4412b8ca6d72, firstname='Sebastian', lastname='Mueller', birthday=1970-01-17T22:29:31.154Z, age=48}
2018-07-02 00:29:46.506  INFO 13591 --- [lication.main()] c.g.d.s.custom.Application               : Comparison - Old entity: User{id=084941a8-6d1a-41d6-94ee-4412b8ca6d72, firstname='Sebastian', lastname='Mueller', birthday=1970-01-17T22:29:31.154Z, age=48}
2018-07-02 00:29:46.506  INFO 13591 --- [lication.main()] c.g.d.s.custom.Application               : Comparison - New entity: User{id=084941a8-6d1a-41d6-94ee-4412b8ca6d72, firstname='Sebastian', lastname='Mueller', birthday=1970-01-17T22:29:31.154Z, age=48}