org.apache.druid.emitter.kafka.MemoryBoundLinkedBlockingQueue Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of kafka-emitter Show documentation

Druid emitter extension to support kafka

There is a newer version: 31.0.0

/*
 * 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.druid.emitter.kafka;

import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.atomic.AtomicLong;

/**
 * Similar to LinkedBlockingQueue but can be bounded by the total byte size of the items present in the queue
 * rather than number of items.
 */
public class MemoryBoundLinkedBlockingQueue
{
  private final long memoryBound;
  private final AtomicLong currentMemory;
  private final LinkedBlockingQueue> queue;

  public MemoryBoundLinkedBlockingQueue(long memoryBound)
  {
    this.memoryBound = memoryBound;
    this.currentMemory = new AtomicLong(0L);
    this.queue = new LinkedBlockingQueue<>();
  }

  // returns true/false depending on whether item was added or not
  public boolean offer(ObjectContainer item)
  {
    final long itemLength = item.getSize();

    if (currentMemory.addAndGet(itemLength) <= memoryBound) {
      if (queue.offer(item)) {
        return true;
      }
    }
    currentMemory.addAndGet(-itemLength);
    return false;
  }

  // blocks until at least one item is available to take
  public ObjectContainer take() throws InterruptedException
  {
    final ObjectContainer ret = queue.take();
    currentMemory.addAndGet(-ret.getSize());
    return ret;
  }

  public static class ObjectContainer
  {
    private T data;
    private long size;

    ObjectContainer(T data, long size)
    {
      this.data = data;
      this.size = size;
    }

    public T getData()
    {
      return data;
    }

    public long getSize()
    {
      return size;
    }
  }
}