001/**
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018package org.apache.hadoop.hbase.ipc;
019
020import java.util.concurrent.BlockingQueue;
021import org.apache.hadoop.conf.Configuration;
022import org.apache.yetus.audience.InterfaceAudience;
023import org.apache.yetus.audience.InterfaceStability;
024
025/**
026 * Abstract class template for defining a pluggable blocking queue implementation to be used
027 * by the 'pluggable' call queue type in the RpcExecutor.
028 *
029 * The intention is that the constructor shape helps re-inforce the expected parameters needed
030 * to match up to how the RpcExecutor will instantiate instances of the queue.
031 *
032 * If the implementation class implements the
033 * {@link org.apache.hadoop.hbase.conf.ConfigurationObserver} interface, it will also be wired
034 * into configuration changes.
035 *
036 * Instantiation requires a constructor with {@code
037 *     final int maxQueueLength,
038 *     final PriorityFunction priority,
039 *     final Configuration conf)}
040 *  as the arguments.
041 */
042@InterfaceAudience.Public
043@InterfaceStability.Evolving
044public abstract class PluggableBlockingQueue implements BlockingQueue<CallRunner> {
045  protected final int maxQueueLength;
046  protected final PriorityFunction priority;
047  protected final Configuration conf;
048
049  public PluggableBlockingQueue(final int maxQueueLength,
050        final PriorityFunction priority, final Configuration conf) {
051    this.maxQueueLength = maxQueueLength;
052    this.priority = priority;
053    this.conf = conf;
054  }
055}