Interface Transformer

future-java/src/main/java/io/trane/future/Transformer.java:9–26

Interface to be used by future.transform. @param the type of the future value. @param the result type of the transformation.

 * @param <U>  the result type of the transformation.
 */
public interface Transformer<T, U> {

  /**
   * Transformation called when the future completes with a failure.
   * 
   * @param ex  the failure.
   * @return    the transformed value.
   */
  public U onException(Throwable ex);

  /**
   * Transformation called when the future completes with a value.
   * 
   * @param value  the value.
   * @return       the transformed value.
   */
  public U onValue(T value);
}