AsyncCloseable Interface

Interface for close operations that are asynchronous.

Asynchronously closing a class

In the snippet below, we have a long-lived NetworkResource class. There are some operations such as closing I/O. Instead of returning a sync close(), we use closeAsync() so users' programs don't block waiting for this operation to complete.

NetworkResource resource = new NetworkResource();
 resource.longRunningDownload("https://longdownload.com")
     .subscribe(
         byteBuffer -> System.out.println("Buffer received: " + byteBuffer),
         error -> System.err.printf("Error occurred while downloading: %s%n", error),
         () -> System.out.println("Completed download operation."));

 System.out.println("Press enter to stop downloading.");
 System.in.read();

 // We block here because it is the end of the main Program function. A real-life program may chain this
 // with some other close operations like save download/program state, etc.
 resource.closeAsync().block();