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 org.apache.cassandra.simulator.systems;
  
  import java.util.concurrent.Callable;
  import java.util.function.Supplier;
  
  import org.apache.cassandra.utils.Shared;
  
  import static org.apache.cassandra.utils.Shared.Scope.SIMULATION;
  
  @Shared(scope = SIMULATION)
  public class NonInterceptible
  {
      @Shared(scope = SIMULATION)
      public enum Permit { REQUIRED, OPTIONAL }
  
      private static final ThreadLocal<Permit> PERMIT = new ThreadLocal<>();
  
      public static boolean isPermitted(Permit permit)
      {
          Permit current = PERMIT.get();
          return current != null && current.compareTo(permit) >= 0;
      }
  
      public static boolean isPermitted()
      {
          return PERMIT.get() != null;
      }
  
      public static void execute(Permit permit, Runnable runnable)
      {
          if (isPermitted())
          {
              runnable.run();
          }
          else
          {
              PERMIT.set(permit);
              try
              {
                  runnable.run();
              }
              finally
              {
                  PERMIT.set(null);
              }
          }
      }
  
      public static <V> V apply(Permit permit, Supplier<V> supplier)
      {
          if (isPermitted())
          {
              return supplier.get();
          }
          else
          {
              PERMIT.set(permit);
              try
              {
                  return supplier.get();
              }
              finally
              {
                  PERMIT.set(null);
              }
          }
      }
  
      public static <V> V call(Permit permit, Callable<V> call) throws Exception
      {
          if (isPermitted())
          {
              return call.call();
          }
          else
          {
              PERMIT.set(permit);
              try
              {
                  return call.call();
              }
              finally
              {
                  PERMIT.set(null);
              }
          }
      }
  }
  