How to make Active Objects Comparable?

[grundic]

Hello.

I got bunch of active objects, which I request via my service. Then I would like to put them exactly in that order to map (as keys).

I tryed HashMap and LinkedHashMap - both throw me an exception

java.lang.ClassCastException: $Proxy1473 cannot be cast to java.lang.Comparable

I tryed to implement my entity's interface (@Implementation(OptionEntityImpl.class)) and add compareTo method, but it didn't helped.

How can I make my active objects Comparable?

Thanks in advance.

[jhinch (Atlassian)]

I would think that provided your Entity interface extends Comparable it would work. Something like this

@Implementation(OptionEntityImpl.class)
public interface OptionEntity extends Entity, Comparable<OptionEntity> {

}

class OptionEntityImpl implements Comparable<OptionEntity> {
  private final OptionEntity delegate;
  public OptionEntityImpl(OptionEntity delegate) {
    this.delegate = delegate;
  }
  public int compareTo(OptionEntity delegate) {
    // add compareTo implementation here
  }
}

[Carl Myers]

This doesn't seem to work for me - I don't understand how, if I implement that interface, it will make AO use my implementation - it uses dynamic proxies.

I tried having my interface implement comparable as well as entity and now I get NPEs from AO when it initializes:

Interface looks like:

public interface AttachmentInfo extends Entity, Comparable<AttachmentInfo> {

Exceptions look like:

java.lang.NullPointerException

at java.lang.Class.isAssignableFrom(Native Method)

at net.java.ao.types.TypeManager.getType(TypeManager.java:51)

at net.java.ao.types.TypeManager.getType(TypeManager.java:45)

at net.java.ao.Common.getValueFields(Common.java:486)

at net.java.ao.EntityManager.create(EntityManager.java:425)

at com.atlassian.activeobjects.internal.EntityManagedActiveObjects.create(EntityManagedActiveObjects.java:89)

at <Method where I try to create an object>

[Carl Myers]

FWIW, I figured out that I probably don't want that anyways. The objects didn't really have a natural sorting. I wanted to preserve the order I inserted them, but also deduplicate them (using set semantics). I don't think TreeSet is the right thing for that here, and I'm not aware of a data structure good for that, so I used two. I kept a list to preserve order I wanted, and a set to dedupe. I consulted the set first, to see if the object was "already had", then inserted it into both if it wasn't seen before, so the list kept order preserved.