Java 类com.facebook.imagepipeline.producers.FetchState 实例源码

@Override
public void fetch(final FetchState fetchState, final Callback callback) {
    final Future<?> future = mExecutorService.submit(
            new Runnable() {
                @Override
                public void run() {
                    HttpURLConnection connection = null;
                    Uri uri = fetchState.getUri();
                    String scheme = uri.getScheme();
                    String uriString = fetchState.getUri().toString();
                    while (true) {
                        String nextUriString;
                        String nextScheme;
                        InputStream is;
                        try {
                            connection = createConnection(uriString);
                            nextUriString = connection.getHeaderField("Location");
                            nextScheme = (nextUriString == null) ? null : Uri.parse(nextUriString).getScheme();
                            if (nextUriString == null || nextScheme.equals(scheme)) {
                                is = connection.getInputStream();
                                callback.onResponse(is, -1);
                                break;
                            }
                            uriString = nextUriString;
                            scheme = nextScheme;
                        } catch (Exception e) {
                            callback.onFailure(e);
                            break;
                        } finally {
                            if (connection != null) {
                                connection.disconnect();
                            }
                        }
                    }

                }
            });
    fetchState.getContext().addCallbacks(
            new BaseProducerContextCallbacks() {
                @Override
                public void onCancellationRequested() {
                    if (future.cancel(false)) {
                        callback.onCancellation();
                    }
                }
            });
}