/*
 * 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.drill.exec.memory;

import com.codahale.metrics.Gauge;
import com.google.common.annotations.VisibleForTesting;
import org.apache.drill.exec.metrics.DrillMetrics;

/**
 * The root allocator for using direct memory inside a Drillbit. Supports creating a
 * tree of descendant child allocators.
 */
public class RootAllocator extends BaseAllocator {

  public RootAllocator(final long limit) {
    super(null, "ROOT", 0, limit);
    DrillMetrics.register("drill.allocator.root.used", new Gauge<Long>() {
      @Override
      public Long getValue() {
        return getAllocatedMemory();
      }
    });
    DrillMetrics.register("drill.allocator.root.peak", new Gauge<Long>() {
      @Override
      public Long getValue() {
        return getPeakMemoryAllocation();
      }
    });
  }

  /**
   * Verify the accounting state of the allocation system.
   */
  @VisibleForTesting
  public void verify() {
    verifyAllocator();
  }
}