class UniqueIndex extends AbstractAttributeIndex<A,O> implements OnHeapTypeIndex {

    protected UniqueIndex(Factory<ConcurrentMap<A,O>> indexMapFactory, Attribute<O, A> attribute)	{
        super(attribute, new HashSet<Class<? extends Query>>() {{
            add(Equal.class);
            add(In.class);
        }});
        this.indexMapFactory = indexMapFactory;
        this.indexMap = indexMapFactory.create();
    }

    protected  UniqueIndex(Factory<ConcurrentMap<A,O>> indexMapFactory, Attribute<O, A> attribute);

}