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.utils.concurrent;
  
  /**
   * An object that needs ref counting does the two following:
   *   - defines a Tidy object that will cleanup once it's gone,
   *     (this must retain no references to the object we're tracking (only its resources and how to clean up))
   * Then, one of two options:
   * 1) Construct a Ref directly pointing to it, and always use this Ref; or
   * 2)
   *   - implements RefCounted
   *   - encapsulates a Ref, we'll call selfRef, to which it proxies all calls to RefCounted behaviours
   *   - users must ensure no references to the selfRef leak, or are retained outside of a method scope.
   *     (to ensure the selfRef is collected with the object, so that leaks may be detected and corrected)
   */
  public interface RefCounted<T>
  {
      /**
       * @return the a new Ref() to the managed object, incrementing its refcount, or null if it is already released
       */
      public Ref<T> tryRef();
  
      public Ref<T> ref();
  
      public static interface Tidy
      {
          void tidy() throws Exception;
          String name();
      }
  }
  