Java By Comparison

Use Optionals as Streams

class BackupJob {

    Communicator communicator;
    Storage storage;

    void backupToEarth() {
        Optional<Connection> connectionOptional =
                communicator.getConnectionToEarth();
        if (!connectionOptional.isPresent()) {
            throw new IllegalStateException();
        }

        Connection connection = connectionOptional.get();
        if (!connection.isFree()) {
            throw new IllegalStateException();
        }

        connection.send(storage.getBackup());
    }
}

In the previous comparisons, we’ve shown that Optional can be a good replacement for null. But it’s not just that, and there’s a good reason why the class was added to lambda expressions in Java. An Optional is also a special kind of stream, one with either zero or exactly one ...