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.api;
  
  import java.util.concurrent.TimeUnit;
  
  import accord.utils.async.Cancellable;
  
  /**
   * A simple task execution interface
   */
  public interface Scheduler
  {
      Scheduled CANCELLED = new Scheduled()
      {
          @Override
          public void cancel()
          {
          }
  
          @Override
          public boolean isDone()
          {
              return true;
          }
      };
  
      Scheduler NEVER_RUN_SCHEDULED = new Scheduler()
      {
          @Override
          public Scheduled recurring(Runnable run, long delay, TimeUnit units)
          {
              return CANCELLED;
          }
  
          @Override
          public Scheduled once(Runnable run, long delay, TimeUnit units)
          {
              return CANCELLED;
          }
  
          @Override
          public Scheduled selfRecurring(Runnable run, long delay, TimeUnit units)
          {
              return CANCELLED;
          }
  
          @Override
          public void now(Runnable run)
          {
              run.run();
          }
      };
  
      interface Scheduled extends Cancellable
      {
          @Override
          void cancel();
          boolean isDone();
      }
  
      default Scheduled recurring(Runnable run) { return recurring(run, 1L, TimeUnit.SECONDS); }
      Scheduled recurring(Runnable run, long delay, TimeUnit units);
  
      Scheduled once(Runnable run, long delay, TimeUnit units);
      Scheduled selfRecurring(Runnable run, long delay, TimeUnit units);
      void now(Runnable run);
  }
  