[MDSAL-550] Consider further specializing AugmentableCodecDataObject

Tue, 1 Feb 2022 19:06:02 +0000

Keyed lists end up being implemented with a combination of AugmentableCodecDataObject and interface-specific implementation of Identifiable.key(), which routes back to CodecDataObject.codecKey().

As a keyed list is always augmentable, it would probably end up being advantageous to have another base class specialization, which would provide the implementation of key, i.e.:

public abstract IdenfiableAugmentableCodecDataObject<I extends Identifier<T>, T extends DataObject & Augmentable<T> & Identifiable<I>>
        extends AugmentableCodecDataObject<T> implements Identifiable<I> {

    private static final VarHandle CACHED_KEY;

    static {
        try {
            CACHED_KEY = MethodHandles.lookup().findVarHandle(IdenfiableAugmentableCodecDataObject.class,
                "cachedKey", Identifier.class);
        } catch (ReflectiveOperationException e) {
            throw new ExceptionInInitializerError(e);
        }
    }

    // Used via VarHandle
    @SuppressWarnings("unused")
    private volatile I cachedKey;

    @Override
    public final I key() {
        return (I) codecKey(CACHED_KEY);
    }
}

Hence we end up generating a bit less code, as well as make the class layout a bit more normalized. The number of implementations of Identifiable.key() should also go down (as low as two with MDSAL-549), potentially helping JIT.

OpenDaylight JIRA

[MDSAL-550] Consider further specializing AugmentableCodecDataObject