[
Date Prev][
Date Next][
Thread Prev][
Thread Next][
Date Index][
Thread Index]
[
List Home]
Re: [aspectj-users] How to create "conditional ITDs"?
|
Take a look at -Xhasmember option to ajc. You should be able to do something along the following lines:
interface NeedsPrePersist {
}
declare parents: !hasfield(@PrePersist * *) && (@Entity *) extends NeedPrePersist;
Then introduce fields and methods to only types that implement NeedPrePersist.
-Ramnivas
On Tue, Aug 4, 2009 at 3:32 PM, Matthew Adams
<matthew@xxxxxxxxxxxxxxx> wrote:
Hi all,
I was wondering how it might be possible to achieve what I'm calling a
conditional inter-type declaration.
Here's a simple auditing example. For a JPA entity, I want to
introduce a @PrePersist method if and only if the target class doesn't
have one because it's an error to have multiple @PrePersist methods on
an entity. If it already has a @PrePersist method, I want to execute
advice after the target instance's @PrePersist method is invoked by
the JPA implementation. Same for @PreUpdate.
The example below will work for Person, but not for Document --
Document will end up with two @PrePersist methods. How can I refactor
this to work for both?
========
@Entity
public class Document {
// ...
@PrePersist
private void prePersist() { /* ... */ }
}
========
@Entity
public class Person {
// ...
}
========
// works only for an @Entity that DOES NOT define a @PrePersist or a
@PreUpdate method
public aspect AuditingItd {
private interface Auditable {
}
declare parents: (@javax.persistence.Entity *) implements Auditable;
@Column(name = "updated")
private Date Auditable.updated;
@PrePersist
private void Auditable.auditablePrePersist() {
updated = new Date();
}
@PreUpdate
private void Auditable.auditablePreUpdate() {
updated = new Date();
}
}
=========
-matthew
--
mailto:matthew@xxxxxxxxxxxxxxx
skype:matthewadams12
yahoo:matthewadams
aol:matthewadams12
google-talk:matthewadams12@xxxxxxxxx
msn:matthew@xxxxxxxxxxxxxxx
http://matthewadams.me
http://www.linkedin.com/in/matthewadams
_______________________________________________
aspectj-users mailing list
aspectj-users@xxxxxxxxxxx
https://dev.eclipse.org/mailman/listinfo/aspectj-users