package org.warp.commonutils.concurrency.future;

import java.util.List;
import java.util.concurrent.CompletableFuture;
import java.util.stream.Collectors;

public class FutureUtils {

	/**
	 * Waits for *all* futures to complete and returns a list of results. If *any* future completes exceptionally then the
	 * resulting future will also complete exceptionally.
	 *
	 * @param futures
	 * @param <T>
	 * @return
	 */
	public static <T> CompletableFuture<List<T>> all(List<CompletableFuture<T>> futures) {
		CompletableFuture[] cfs = futures.toArray(CompletableFuture[]::new);

		return CompletableFuture.allOf(cfs)
				.thenApply(ignored -> futures.stream().map(CompletableFuture::join).collect(Collectors.toList()));
	}
}