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.memory;
  
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  /**
   * Counting allocation listener. It counts the number of times it has been invoked, and how much
   * memory allocation it has seen When set to 'expand on fail', it attempts to expand the associated
   * allocator's limit.
   */
  final class CountingAllocationListener implements AllocationListener {
    private int numPreCalls;
    private int numCalls;
    private int numReleaseCalls;
    private int numChildren;
    private long totalMem;
    private long currentMem;
    private boolean expandOnFail;
    @Nullable BufferAllocator expandAlloc;
    long expandLimit;
  
    CountingAllocationListener() {
      this.numCalls = 0;
      this.numChildren = 0;
      this.totalMem = 0;
      this.currentMem = 0;
      this.expandOnFail = false;
      this.expandAlloc = null;
      this.expandLimit = 0;
    }
  
    @Override
    public void onPreAllocation(long size) {
      numPreCalls++;
    }
  
    @Override
    public void onAllocation(long size) {
      numCalls++;
      totalMem += size;
      currentMem += size;
    }
  
    @Override
    public boolean onFailedAllocation(long size, AllocationOutcome outcome) {
      if (expandOnFail) {
        if (expandAlloc == null) {
          throw new IllegalStateException(
              "expandAlloc must be non-null because this " + "listener is set to expand on failure.");
        }
        expandAlloc.setLimit(expandLimit);
        return true;
      }
      return false;
    }
  
    @Override
    public void onRelease(long size) {
      numReleaseCalls++;
      currentMem -= size;
    }
  
    @Override
    public void onChildAdded(BufferAllocator parentAllocator, BufferAllocator childAllocator) {
      ++numChildren;
    }
  
    @Override
    public void onChildRemoved(BufferAllocator parentAllocator, BufferAllocator childAllocator) {
      --numChildren;
    }
  
    void setExpandOnFail(BufferAllocator expandAlloc, long expandLimit) {
      this.expandOnFail = true;
      this.expandAlloc = expandAlloc;
      this.expandLimit = expandLimit;
    }
  
    int getNumPreCalls() {
      return numPreCalls;
    }
  
    int getNumReleaseCalls() {
      return numReleaseCalls;
    }
  
    int getNumCalls() {
      return numCalls;
    }
  
    int getNumChildren() {
      return numChildren;
    }
  
    long getTotalMem() {
      return totalMem;
    }
  
    long getCurrentMem() {
      return currentMem;
    }
  }
  