# Package org.zkoss.zk.au

- Interface Summary
  Interface | Description
  --- | ---
  AuDecoder | Used to decode the custom format of the AU requests.
  AuService | An AU request service used to handle the AU requests (`AuRequest`).
  AuWriter | Represents a writer that is used to send the output back to the client, when processing `AuRequest`.
  DeferredValue | Used with `AbstractComponent.smartUpdate(java.lang.String, java.lang.Object)` to represent the value of a smart update that shall be evaluated only in the rendering phase (rather than in the event processing phase).

- Class Summary
  Class | Description
  --- | ---
  AuRequest | A request sent from the client to the server.
  AuRequests | Utilities to convert `AuRequest` to `Event` or its deriving classes.
  AuResponse | A response sent from the server to the client via `UiEngine`.
  AuResponse.JSONComponent |
  AuResponse.JSONDate |
  AuWriters | Utilities to instantiate an implementation of `AuWriter`.

- Exception Summary
  Exception | Description
  --- | ---
  RequestOutOfSequenceException | Indicates a request is out-of-sequence, and the request shall be ignored.