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.client.backoff;
019
020import org.apache.hadoop.conf.Configuration;
021import org.apache.hadoop.hbase.ServerName;
022import org.apache.yetus.audience.InterfaceAudience;
023import org.apache.yetus.audience.InterfaceStability;
024import org.slf4j.Logger;
025import org.slf4j.LoggerFactory;
026import org.apache.hadoop.hbase.util.ReflectionUtils;
027
028@InterfaceAudience.Private
029@InterfaceStability.Evolving
030public final class ClientBackoffPolicyFactory {
031
032  private static final Logger LOG = LoggerFactory.getLogger(ClientBackoffPolicyFactory.class);
033
034  private ClientBackoffPolicyFactory() {
035  }
036
037  public static ClientBackoffPolicy create(Configuration conf) {
038    // create the backoff policy
039    String className =
040        conf.get(ClientBackoffPolicy.BACKOFF_POLICY_CLASS, NoBackoffPolicy.class
041            .getName());
042      return ReflectionUtils.instantiateWithCustomCtor(className,
043          new Class<?>[] { Configuration.class }, new Object[] { conf });
044  }
045
046  /**
047   * Default backoff policy that doesn't create any backoff for the client, regardless of load
048   */
049  public static class NoBackoffPolicy implements ClientBackoffPolicy {
050    public NoBackoffPolicy(Configuration conf){
051      // necessary to meet contract
052    }
053
054    @Override
055    public long getBackoffTime(ServerName serverName, byte[] region, ServerStatistics stats) {
056      return 0;
057    }
058  }
059}