resources.java

    @org.junit.Test
    public void name() throws Exception {
        Observable<String> obs = Observable.create(customLogic());
    }

    private Observable.OnSubscribe<String> customLogic() {
        return subscriber -> {
            try {
                if (!subscriber.isUnsubscribed()) {
                    Scanner scanner = new Scanner("wurst.file.c");

                    subscriber.add(Subscriptions.create(scanner::close));

                    while (scanner.hasNext()) {
                        String line = scanner.nextLine();

                        if (subscriber.isUnsubscribed()) {
                            break;
                        }
                        subscriber.onNext(line);
                    }
                    subscriber.onCompleted();
                }
            } catch (Exception e) {
                if (!subscriber.isUnsubscribed()) {
                    subscriber.onError(e);
                }
            }
        };
    }

       @Test
    public void t1() throws Exception {
        Func0<Scanner> createFactory = () -> {
            return new Scanner("wurst.file.c");
        };

        Func1<Scanner, Observable<String>> observableFactory = (resource) -> {
            return PublishSubject.<String>create(subscriber -> {
                while (resource.hasNext()) {
                    String line = resource.nextLine();

                    subscriber.onNext(line);
                }

                subscriber.onCompleted();
            }).asObservable();
        };

        Action1<Scanner> disposeFactory = (resource) -> {
            resource.close();
        };

        Observable<String> using = Observable.using(createFactory, observableFactory, disposeFactory);
    }