/*
    * Copyright 2014 The Netty Project
    *
    * The Netty Project licenses this file to you 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 io.netty.util.concurrent;
  
  import io.netty.util.internal.PromiseNotificationUtil;
  import io.netty.util.internal.logging.InternalLogger;
  import io.netty.util.internal.logging.InternalLoggerFactory;
  
  import static io.netty.util.internal.ObjectUtil.checkNotNull;
  
  /**
   * {@link GenericFutureListener} implementation which takes other {@link Promise}s
   * and notifies them on completion.
   *
   * @param <V> the type of value returned by the future
   * @param <F> the type of future
   */
  public class PromiseNotifier<V, F extends Future<V>> implements GenericFutureListener<F> {
  
      private static final InternalLogger logger = InternalLoggerFactory.getInstance(PromiseNotifier.class);
      private final Promise<? super V>[] promises;
      private final boolean logNotifyFailure;
  
      /**
       * Create a new instance.
       *
       * @param promises  the {@link Promise}s to notify once this {@link GenericFutureListener} is notified.
       */
      @SafeVarargs
      public PromiseNotifier(Promise<? super V>... promises) {
          this(true, promises);
      }
  
      /**
       * Create a new instance.
       *
       * @param logNotifyFailure {@code true} if logging should be done in case notification fails.
       * @param promises  the {@link Promise}s to notify once this {@link GenericFutureListener} is notified.
       */
      @SafeVarargs
      public PromiseNotifier(boolean logNotifyFailure, Promise<? super V>... promises) {
          checkNotNull(promises, "promises");
          for (Promise<? super V> promise: promises) {
              if (promise == null) {
                  throw new IllegalArgumentException("promises contains null Promise");
              }
          }
          this.promises = promises.clone();
          this.logNotifyFailure = logNotifyFailure;
      }
  
      @Override
      public void operationComplete(F future) throws Exception {
          InternalLogger internalLogger = logNotifyFailure ? logger : null;
          if (future.isSuccess()) {
              V result = future.get();
              for (Promise<? super V> p: promises) {
                  PromiseNotificationUtil.trySuccess(p, result, internalLogger);
              }
          } else if (future.isCancelled()) {
              for (Promise<? super V> p: promises) {
                  PromiseNotificationUtil.tryCancel(p, internalLogger);
              }
          } else {
              Throwable cause = future.cause();
              for (Promise<? super V> p: promises) {
                  PromiseNotificationUtil.tryFailure(p, cause, internalLogger);
              }
          }
      }
  }