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 */
018
019package org.apache.hadoop.hdfs.server.namenode.ha;
020
021import java.util.concurrent.atomic.AtomicBoolean;
022
023import org.apache.hadoop.conf.Configuration;
024import org.apache.hadoop.io.retry.FailoverProxyProvider;
025
026public abstract class AbstractNNFailoverProxyProvider<T> implements
027   FailoverProxyProvider <T> {
028
029  protected AtomicBoolean fallbackToSimpleAuth;
030
031  /**
032   * Inquire whether logical HA URI is used for the implementation. If it is
033   * used, a special token handling may be needed to make sure a token acquired 
034   * from a node in the HA pair can be used against the other node. 
035   *
036   * @return true if logical HA URI is used. false, if not used.
037   */
038  public abstract boolean useLogicalURI(); 
039
040  /**
041   * Set for tracking if a secure client falls back to simple auth.  This method
042   * is synchronized only to stifle a Findbugs warning.
043   *
044   * @param fallbackToSimpleAuth - set to true or false during this method to
045   *   indicate if a secure client falls back to simple auth
046   */
047  public synchronized void setFallbackToSimpleAuth(
048      AtomicBoolean fallbackToSimpleAuth) {
049    this.fallbackToSimpleAuth = fallbackToSimpleAuth;
050  }
051}