content: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF 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 accord.impl.basic;
  
  import java.util.List;
  import java.util.concurrent.TimeUnit;
  import java.util.function.Predicate;
  
  public interface PendingQueue extends Iterable<Pending>
  {
      void add(Pending item);
      void addNoDelay(Pending item);
      void add(Pending item, long delay, TimeUnit units);
  
      /**
       * Register an item we intend to add later.
       * This is primarily for tracking the number of recurring tasks there are pending to run,
       * including those that are being tracked pre-submission as e.g. tasks in a logical executor that cannot be
       * scheduled until the preceding tasks have completed.
       */
      void preregister(Pending item);
  
      boolean remove(Pending item);
      Pending poll();
      List<Pending> drain(Predicate<Pending> toDrain);
      int size();
      long nowInMillis();
  
      boolean hasNonRecurring();
  }
  