# Interface Callback<T>

All Superinterfaces:
  `FailureCallback<T>, SuccessCallback<T>`

All Known Implementing Classes:
  `CallbackAdapter`

public interface Callback<T> extends SuccessCallback<T>, FailureCallback<T>
Simple interface that allows asynchronous code to perform a parameterized callback or failure in a similar way to GWT's callback interface.

- ## Method Summary

  ### Methods inherited from interface FailureCallback

  `onError`
  Modifier and Type
  Method
  Description
  `void`
  `onError(Object sender, Throwable err, int errorCode, String errorMessage)`
  Invoked when the async method throws an exception

  ### Methods inherited from interface SuccessCallback

  `onSucess`
  Modifier and Type
  Method
  Description
  `void`
  `onSucess(T value)`
  Invoked when the async method returns with a successful value