Kryonet -- How can I register classes within my class?

Question

I have the following class:

public class QueryResults {
    protected Set<String> resultList = new HashSet<String>();
    protected long executionTime = 0;

    public long getExecutionTime() { return executionTime; }
    [...]
}

And I register it as so:

Registrar.RegisterClass(this, QueryResults.class);
------------
public class Registrar {
    public static void RegisterClass(Node n, Class theClass) {
        Map<String, Node> nodeMap = Node.getNodeMap();
        for (Map.Entry<String, Node> node : nodeMap.entrySet()) {
            if (node.getKey().equals(n.getHostname())) {
                Log.info("Registering " + theClass.getSimpleName() + " for " + node.getValue().getHostname());
                node.getValue().getServer().getConnection().getKryo().register(theClass);
                node.getValue().getClient().getConnection().getKryo().register(theClass);
            }
        }
    }
}

This has worked well until attempting to serialize QueryResults, due to it containing a container, in this case a HashSet (We've tried an ArrayList as well, with the same results).

On the endpoint populating and ultimately serializing this class to send back to the caller, I get this output:

Exception in thread "Server" com.esotericsoftware.kryo.KryoException:
java.lang.IllegalArgumentException: Class is not registered: java.util.HashSet

Note: To register this class use: kryo.register(java.util.HashSet.class);

If I explicitly call Registrar.RegisterClass(this, HashSet.class);, everything works swimmingly. However, this can be annoying once we start to implement more advanced classes, with many types of containers.

Am I doing something wrong?

Which serialization strategy is used in your kryo instances? BeanSerializer may cause failures if your pojo is not a valid bean (doesn't have getters and setters), while JavaSerializer needs a Serializable pojo. — Michael Cheremuhin, Sep 17 '15 at 04:44
Also try please a code snippet from my anwser. I guess it's not an option to use it for every collection field, but it may help with investigation. — Michael Cheremuhin, Sep 17 '15 at 04:51

Michael Cheremuhin · Answer 1 · 2015-09-17T00:20:27.213

1

How about using kryo bind annotations:

public class QueryResults {

    @CollectionSerializer.BindCollection(
         elementClass = QueryResults.class,
         elementSerializer = DefaultSerializers.StringSerializer.class) 
    protected Set<String> resultList = new HashSet<String>();

    ...
}

Also check a set of additional kryo serialisers.

edited Sep 17 '15 at 00:20

answered Sep 16 '15 at 12:02

Michael Cheremuhin

1,381
11
17

I haven't had a chance to try this for my scenarios yet, but the bounty is going to expire so I'm going to go ahead and award it to your answer. I'll try to respond back with my results later this week. – MrDuk Sep 21 '15 at 05:27

Kryonet -- How can I register classes within my class?

1 Answers1