Network Events

By default, system events aren’t sent over the network. To send events over the network, you should mark the event as ServerEvent, BroadcastEvent or OwnerEvent

Note

If an event is marked as a network event, its fields are all replicated by default.

ServerEvent

Events annotated with @ServerEvent, are sent to the server. Only systems on the server will then be able to process it. Typically those events are requests to the server to confirm a gameplay related change. For that reason their name often ends with Request instead of Event.

When events marked with @ServerEvent are sent on the client, they will be replicated to the server as well so that they can be actioned there.

This is very important for events that require action on the part of the server, such as AbstractMoveItemRequest and DropItemRequest.

@ServerEvent
public abstract class AbstractMoveItemRequest implements Event {

@ServerEvent(lagCompensate = true)
public class DropItemRequest implements Event {

Note

You can also specify the lagCompensate element when marking events with the @ServerEvent annotation, as seen from DropItemEvent It is false by default. If set to true, however, the positioning of all characters on the server will be rewound to simulate the conditions on the client when the event was initially sent before the event is processed by the server.

In the case of DropItemRequest, there is a need for lagCompensate to be set to true as the item should be dropped at the position where the character was when the request was initially sent, rather than the position where the character is when the event is received by the server. This thus takes into account the time taken for the request to be sent from the client to the server.

BroadcastEvent

Events annotated with @BroadcastEvent are sent by the server to all clients.

Todo

What happens if a client tries to send this event?

OwnerEvent

Events annotated with @OwnerEvent are sent by the server to the client that owns the entity. Typically a client only owns its character and stuff related to it.

Note

If a system on a client/server is responsible for processing an event, it can and should also be defined via a network filter which can be specified in the @RegisterSystem annotation of the service or within @ReceiveEvent annotation of the handling method. See more detail about provessing an event in Processing events