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.arrow.dataset.jni;
  
  /** C++ memory pool(arrow::MemoryPool)'s Java mapped instance. */
  public class NativeMemoryPool implements AutoCloseable {
    private final long nativeInstanceId;
  
    private NativeMemoryPool(long nativeInstanceId) {
      this.nativeInstanceId = nativeInstanceId;
    }
  
    /** Get the default memory pool. This will return arrow::default_memory_pool() directly. */
    public static NativeMemoryPool getDefault() {
      JniLoader.get().ensureLoaded();
      return new NativeMemoryPool(getDefaultMemoryPool());
    }
  
    /**
     * Create a listenable memory pool (see also: arrow::ReservationListenableMemoryPool) with a
     * specific listener. All buffers created from the memory pool should take enough reservation from
     * the listener in advance.
     */
    public static NativeMemoryPool createListenable(ReservationListener listener) {
      JniLoader.get().ensureLoaded();
      return new NativeMemoryPool(createListenableMemoryPool(listener));
    }
  
    /** Return native instance ID of this memory pool. */
    public long getNativeInstanceId() {
      return nativeInstanceId;
    }
  
    /** Get current allocated bytes. */
    public long getBytesAllocated() {
      return bytesAllocated(nativeInstanceId);
    }
  
    @Override
    public void close() throws Exception {
      releaseMemoryPool(nativeInstanceId);
    }
  
    private static native long getDefaultMemoryPool();
  
    private static native long createListenableMemoryPool(ReservationListener listener);
  
    private static native void releaseMemoryPool(long id);
  
    private static native long bytesAllocated(long id);
  }
  