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    
019    package org.apache.hadoop.hdfs.server.namenode.ha;
020    
021    import java.util.concurrent.atomic.AtomicBoolean;
022    
023    import org.apache.hadoop.conf.Configuration;
024    import org.apache.hadoop.io.retry.FailoverProxyProvider;
025    
026    public 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    }