Vertx: Future异步操作设计

Future相关操作的设计

AsyncResult

AsyncResult表示一个异步操作的结果，这个结果要么是成功的，要么是失败的。

interface AsyncResult<T> {
    T getResult();
    Throwable cause();
    boolean succeeded();
    boolean failed();
    <V> AsyncResult<V> map(Function<T, V> mapper);
    <V> AsyncResult<V> map(V value);
    <V> AsyncResult<V> mapEmpty();
    AsyncResult<T> otherwise(T value);
    AsyncResult<T> otherwise(Function<Throwable, T> mapper);
    AsyncResult<T> otherwiseEmpty();
}

Future

Future表示一个尚未完成的异步操作，并继承自AsyncResult

interface Future<T>
    extends AsyncResult<T> {
    boolean isComplete();
    Future<T> onComplete(Handler<AsyncResult<T>> handler);
    Future<T> onSuccess(Handler<T> handler);
    Future<T> onFailure(Handler<Throwable> handler);
    <V> Future<V> compose(Function<T, Future<V>> mapper);
    <V> Future<V> compose(Function<T, Future<V>> successMapper, 
                      Function<Throwable, Future<V>> failureMapper);
    Future<T> recover(Function<Throwable, Future<T>> mapper);
    <V> Future<V> transform(Function<AsyncResult<T>, Future<V>> mapper);
    <V> Future<T> eventually(Function<Void, Future<V>> mapper);
    CompletionStage<T> toCompletionState();
}