/** Gets the top-level data source supplier to be used by a controller. */
protected Supplier<DataSource<IMAGE>> obtainDataSourceSupplier() {
if (mDataSourceSupplier != null) {
return mDataSourceSupplier;
}
Supplier<DataSource<IMAGE>> supplier = null;
// final image supplier;
if (mImageRequest != null) {
supplier = getDataSourceSupplierForRequest(mImageRequest);
} else if (mMultiImageRequests != null) {
supplier = getFirstAvailableDataSourceSupplier(mMultiImageRequests);
}
// increasing-quality supplier; highest-quality supplier goes first
if (supplier != null && mLowResImageRequest != null) {
List<Supplier<DataSource<IMAGE>>> suppliers = new ArrayList<Supplier<DataSource<IMAGE>>>(2);
suppliers.add(supplier);
suppliers.add(getDataSourceSupplierForRequest(mLowResImageRequest));
supplier = IncreasingQualityDataSourceSupplier.create(suppliers);
}
// no image requests; use null data source supplier
if (supplier == null) {
supplier = DataSources.getFailedDataSourceSupplier(NO_REQUEST_EXCEPTION);
}
return supplier;
}
