QueueBackinMap example for 3.x

queue-backing0map

public class QueueBackedByMap<I> implements IQueue<I> {

    final IQueue<Long> queue;
    final IMap<Long, I> map;
    final IdGenerator idGenerator;

    public QueueBackedByMap(HazelcastInstance instance, String name) {
        queue = instance.getQueue(name);
        map = instance.getMap(name);
        idGenerator = instance.getIdGenerator(name);
    }
    
    
    .....

    public boolean offer(I item) {
        final long id = idGenerator.newId();
        map.put(id, item);
        if (!queue.offer(id)) {
            map.remove(id);
            return false;
        }
        return true;
    }

    public I poll() {
        final Long id = queue.poll();
        if (id == null) {
            return null;
        }
        final I item = map.get(id);
        return item;
    }
    
    .....
    
}