How do I use a JPARepository inside of a PrePersist Annotation?

Question

I have an alert table which is transactional and an alert type table which is master. I would like to send out an email whenever an alert is added to the table, so I figured I would use PrePersist. However, in my email, I want to include some information that is included in the alert type table.

I have tried to add a reference to the AlertTypeRepository in the Alert class but I can't because my alert class is a @Table and alertTypeRepository is not a column.

Below is my Alert class

@Entity 
@Table 
@Getter 
@Setter 
@NoArgsConstructor
@AllArgsConstructor
public class Alert {
    @Id
    @GeneratedValue
    int id;
    @Column
    String name;
    @Column
    String alertTypeId;
    @Column
    String detailedMessage;
    @Column
    String status;
    @Temporal(TemporalType.TIMESTAMP)
    Date time;
}

Below is my AlertType class

@Entity 
@Table 
@Getter 
@Setter 
@NoArgsConstructor
@AllArgsConstructor
public class AlertType {
    @Id
    @GeneratedValue
    int id;
    @Column
    String name;
    @Column
    String header;
    @Column
    String footer;
    @Column
    String summary;
    @Column
    String deliveryType;
    @Column
    Boolean active ;
    @Column
    String recipients;
}

I would like to have a PrePersist function inside of the Alert class. That allows me to access its corresponding header and footer from the AlertType class.

Answer 1

I figured out a solution so I hope this helps anyone facing a similar issue. Basically I had to create an EntityListener to the Alert class and then add the following class.

@Component
public class AlertListener {

    static AlertTypeRepository alertTypeRepository;

    @Autowired
    public void init(AlertTypeRepository alertTypeRepository)
    {
         this.alertTypeRepository = alertTypeRepository;

    }

    @PrePersist
    public void prePersist(Alert alert) {
        List<AlertType> alertType=  this.alertTypeRepository.findAll();

    }
}

Answer 2

As I know the are two approaches to archive the purpose. Your alterType is not managed by Spring .

1. Define a JPA EntityListener and apply it on your entity class, which does not seem to interest you.
2. The second approach, annotated your entity with Spring @Configurable annotation:

@Configurable(preConstruction = true) 
class AlterType{

@Inject YourRepository bean as normal.
}

To make it work. Firstly you have to add aspectj related jars into your project dependencies. Secondly you can choose load-time weaving or compile-time weaving to handling the injection for you class.

There is an example of aspectj compiler config in Maven can be used for compile-time weaving(note, just for aspectj compiler maven plugin config, I did not use @Configurable here.).