A simple cancellable downloader

downloader

import okhttp3.ResponseBody;
import retrofit2.Call;

public interface Repository {
    Call<ResponseBody> download(String url);
}

public void cancelCurrentDownloadingTask() {
    if (call != null) {
        call.cancel();
    }
}

public Observable<ResponseBody> loadUrlResource(String url) {
        return Observable.create(
                subscriber -> {
                    call = repository.download(url);

                    // keep the local record of 'call' since the actual instance will be replaced.
                    final Call<ResponseBody> downloadCall = call;

                    try {
                        Response<ResponseBody> response = downloadCall.execute();
                        if (response.isSuccessful()) {

                            ResponseBody body = response.body();
                            subscriber.onNext(body);

                            subscriber.onCompleted();
                        } else {
                            subscriber.onError(
                                    new Throwable("Http response error code:" + response.code()));
                        }
                    } catch (IOException e) {
                        e.printStackTrace();

                        if (downloadCall.isCanceled()) {
                            String message =
                                    String.format(
                                            Locale.ENGLISH, ">>> Cancelled request for %s", url);
                            subscriber.onError(new CancelledException(message));
                        } else {
                            subscriber.onError(e);
                        }
                    }
                });
    }