content: /*
   * Copyright 2021-2024 Aklivity Inc.
   *
   * Aklivity 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.aklivity.zilla.runtime.binding.kafka.internal.cache;
  
  import java.util.concurrent.atomic.AtomicInteger;
  
  public abstract class KafkaCacheObject<T extends KafkaCacheObject<T>> implements AutoCloseable
  {
      private final AtomicInteger references;
  
      private volatile boolean closed;
      private volatile boolean closing;
  
      protected KafkaCacheObject()
      {
          this.references = new AtomicInteger(1);
      }
  
      public final T acquire()
      {
          if (closed)
          {
              return null;
          }
          references.incrementAndGet();
          return self();
      }
  
      public final void release()
      {
          final int count = references.decrementAndGet();
          assert count >= 0;
          if (count == 0)
          {
              assert !closed;
              closed = true;
              onClosed();
          }
      }
  
      @Override
      public final void close()
      {
          if (!closing)
          {
              closing = true;
              release();
          }
      }
  
      public final boolean closed()
      {
          return closed;
      }
  
      protected final int references()
      {
          return references.get();
      }
  
      protected abstract T self();
  
      protected abstract void onClosed();
  }
  