# Package org.apache.geode.cache.wan

- Interface Summary
  Interface | Description
  --- | ---
  GatewayEventFilter | Callback for users to filter out events before dispatching to remote distributed system
  GatewayEventSubstitutionFilter<K,V> | Interface `GatewayEventSubstitutionFilter` provides a way to specify a substitute value to be stored in the `GatewayQueueEvent` and enqueued in the `RegionQueue`.
  GatewayQueueEvent<K,V> | Represents `Cache` events going through `GatewaySender`s.
  GatewayReceiver | A GatewayReceiver that receives the events from a `GatewaySender`.
  GatewayReceiverFactory |
  GatewaySender |
  GatewaySenderFactory | Factory to create SerialGatewaySender
  GatewayTransportFilter |

- Class Summary
  Class | Description
  --- | ---
  EventSequenceID | This class wraps 1) DistributedMembershipID 2) ThreadID 3) SequenceID attributes which are used to uniquely identify any Region Operation like create, update, destroy etc.

- Enum Summary
  Enum | Description
  --- | ---
  GatewaySender.OrderPolicy | The order policy.