content: /*
   * Copyright 1999-2018 Alibaba Group Holding Ltd.
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package com.alibaba.csp.sentinel.dashboard.util;
  
  import java.util.List;
  import java.util.Objects;
  import java.util.concurrent.CompletableFuture;
  import java.util.concurrent.TimeUnit;
  import java.util.stream.Collectors;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * @author Eric Zhao
   * @since 1.4.1
   */
  public final class AsyncUtils {
  
      private static final Logger LOG = LoggerFactory.getLogger(AsyncUtils.class);
  
      public static <R> CompletableFuture<R> newFailedFuture(Throwable ex) {
          CompletableFuture<R> future = new CompletableFuture<>();
          future.completeExceptionally(ex);
          return future;
      }
  
      public static <R> CompletableFuture<List<R>> sequenceFuture(List<CompletableFuture<R>> futures) {
          return CompletableFuture.allOf(futures.toArray(new CompletableFuture[0]))
              .thenApply(v -> futures.stream()
                  .map(AsyncUtils::getValue)
                  .filter(Objects::nonNull)
                  .collect(Collectors.toList())
              );
      }
  
      public static <R> CompletableFuture<List<R>> sequenceSuccessFuture(List<CompletableFuture<R>> futures) {
          return CompletableFuture.supplyAsync(() -> futures.parallelStream()
              .map(AsyncUtils::getValue)
              .filter(Objects::nonNull)
              .collect(Collectors.toList())
          );
      }
  
      public static <T> T getValue(CompletableFuture<T> future) {
          try {
              return future.get(10, TimeUnit.SECONDS);
          } catch (Exception ex) {
              LOG.error("getValue for async result failed", ex);
          }
          return null;
      }
  
      public static boolean isSuccessFuture(CompletableFuture future) {
          return future.isDone() && !future.isCompletedExceptionally() && !future.isCancelled();
      }
  
      private AsyncUtils() {}
  }
  