content: /*
   * The Alluxio Open Foundation licenses this work under the Apache License, version 2.0
   * (the "License"). You may not use this work except in compliance with the License, which is
   * available at www.apache.org/licenses/LICENSE-2.0
   *
   * This software is distributed on an "AS IS" basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
   * either express or implied, as more fully set forth in the License.
   *
   * See the NOTICE file distributed with this work for information regarding copyright ownership.
   */
  
  package alluxio.resource;
  
  import io.netty.util.ResourceLeakDetector;
  import io.netty.util.ResourceLeakTracker;
  
  import java.io.Closeable;
  import javax.annotation.Nullable;
  
  /**
   * A {@code CloseableResource<T>} is a wrapper around a resource of type {@code T} which must do
   * some sort of cleanup when it is no longer in use.
   *
   * @param <T> the type of the wrapped resource
   */
  public abstract class CloseableResource<T> implements Closeable {
  
    private static final ResourceLeakDetector<CloseableResource> DETECTOR =
        AlluxioResourceLeakDetectorFactory.instance()
            .newResourceLeakDetector(CloseableResource.class);
  
    private final T mResource;
  
    @Nullable
    private final ResourceLeakTracker<CloseableResource> mTracker = DETECTOR.track(this);
  
    /**
     * Creates a {@link CloseableResource} wrapper around the given resource. This resource will
     * be returned by the {@link CloseableResource#get()} method.
     *
     * @param resource the resource to wrap
     */
    public CloseableResource(T resource) {
      mResource = resource;
    }
  
    /**
     * @return the resource
     */
    public T get() {
      return mResource;
    }
  
    @Override
    public void close() {
      if (mTracker != null) {
        mTracker.close(this);
      }
      closeResource();
    }
  
    /**
     * Performs any cleanup operations necessary when the resource is no longer in use.
     */
    public abstract void closeResource();
  }
  