Util method to process a list of data in parallel.

ParallelRxJavaUtil.java

/**
 * Will process the data with the callable by splitting the data into the specified number of threads.
 * <b>T</b> is ths type of data being parsed, and <b>U</b> is the type of data being returned.
 */
public static <T, U> Iterable<U> parseDataInParallel(@NonNull List<T> data, Function<List<T>, ObservableSource<U>> worker) {
    int threadCount = Runtime.getRuntime().availableProcessors();
    ExecutorService threadPoolExecutor = Executors.newFixedThreadPool(threadCount);
    Scheduler scheduler = Schedulers.from(threadPoolExecutor);

    AtomicInteger groupIndex = new AtomicInteger();

    return Observable.fromIterable(data).groupBy(k -> groupIndex.getAndIncrement() % threadCount)
            .flatMap(group -> group.observeOn(scheduler).toList().flatMapObservable(worker)).blockingIterable();

}



//***EXAMPLE USAGE***
Iterable<List<DataModel>> resultGroups = Util.parseDataInParallel(dataList,
    (sublist) -> {
        List<DataModel> dataModels = new ArrayList<>();
        for (String data : sublist) {
            dataModels.add(DataParser.createData(data));
        }
        return Observable.just(dataModels);
    });

List<DataModel> results = new ArrayList<>();
for (List<DataModel> dataModels : resultGroups) {
    results.addAll(dataModels);
}