# History, Design and Future { #history-design-and-future }

Some time ago, <a href="https://github.com/fastapi/fastapi/issues/3#issuecomment-454956920" class="external-link" target="_blank">a **FastAPI** user asked</a>:

> What’s the history of this project? It seems to have come from nowhere to awesome in a few weeks [...]

Here's a little bit of that history.

## Alternatives { #alternatives }

    }

    private final ClosingFuture<V1> future1;
    private final ClosingFuture<V2> future2;
    private final ClosingFuture<V3> future3;

    private Combiner3(
        ClosingFuture<V1> future1, ClosingFuture<V2> future2, ClosingFuture<V3> future3) {
      super(true, ImmutableList.of(future1, future2, future3));
      this.future1 = future1;
      this.future2 = future2;
      this.future3 = future3;
    }

    }

    private final ClosingFuture<V1> future1;
    private final ClosingFuture<V2> future2;
    private final ClosingFuture<V3> future3;

    private Combiner3(
        ClosingFuture<V1> future1, ClosingFuture<V2> future2, ClosingFuture<V3> future3) {
      super(true, ImmutableList.of(future1, future2, future3));
      this.future1 = future1;
      this.future2 = future2;
      this.future3 = future3;
    }

   *
   * <p>Cancelling a delegate future propagates to input futures once all the delegates complete,
   * either from cancellation or because an input future has completed. If N futures are passed in,
   * and M delegates are cancelled, the remaining M input futures will be cancelled once N - M of
   * the input futures complete. If all the delegates are cancelled, all the input futures will be

    private final ListenableFuture<@Nullable Void> future;
    private boolean called = false;

    private TestCallable(ListenableFuture<@Nullable Void> future) {
      this.future = future;
    }

    @Override
    public ListenableFuture<@Nullable Void> call() throws Exception {
      called = true;
      return future;
    }
  }

    InterruptibleFuture future = new InterruptibleFuture();
    assertTrue(future.cancel(false));
    assertTrue(future.isCancelled());
    assertTrue(future.isDone());
    assertFalse(future.wasInterrupted());
    assertFalse(future.interruptTaskWasCalled);
    CancellationException e = assertThrows(CancellationException.class, () -> future.get());
    assertThat(e).hasCauseThat().isNull();
  }

  }

  /**
   * Invokes {@code future.}{@link Future#get() get()} uninterruptibly.
   *
   * <p>Similar methods:
   *
   * <ul>
   *   <li>To retrieve a result from a {@code Future} that is already done, use {@link
   *       Futures#getDone Futures.getDone}.
   *   <li>To treat {@link InterruptedException} uniformly with other exceptions, use {@link
   *       Futures#getChecked(Future, Class) Futures.getChecked}.

 *       Future} is "completed" even if it is cancelled while its underlying work continues on a
 *       thread, an RPC, etc. The {@code Future} is also "completed" if it fails "early" -- for
 *       example, if the deadline expires on a {@code Future} returned from {@link
 *       Futures#withTimeout} while the {@code Future} it wraps continues its underlying work. So

   * completing the returned {@code Future}.)
   *
   * <p>The returned {@code Future} attempts to keep its cancellation state in sync with that of the
   * input future and that of the future returned by the chain function. That is, if the returned
   * {@code Future} is cancelled, it will attempt to cancel the other two, and if either of the
   * other two is cancelled, the returned {@code Future} will receive a callback in which it will

    InterruptibleFuture future = new InterruptibleFuture();
    assertTrue(future.cancel(false));
    assertTrue(future.isCancelled());
    assertTrue(future.isDone());
    assertFalse(future.wasInterrupted());
    assertFalse(future.interruptTaskWasCalled);
    CancellationException e = assertThrows(CancellationException.class, () -> future.get());
    assertThat(e).hasCauseThat().isNull();
  }