Package org.apache.cassandra.service

Source Code of org.apache.cassandra.service.DatacenterQuorumResponseHandler

package org.apache.cassandra.service;
/*
*
* 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
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* under the License.
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*/


import java.util.concurrent.atomic.AtomicInteger;

import org.apache.cassandra.config.DatabaseDescriptor;
import org.apache.cassandra.db.Table;
import org.apache.cassandra.locator.IEndpointSnitch;
import org.apache.cassandra.locator.NetworkTopologyStrategy;
import org.apache.cassandra.net.Message;
import org.apache.cassandra.thrift.ConsistencyLevel;
import org.apache.cassandra.utils.FBUtilities;

/**
* Datacenter Quorum response handler blocks for a quorum of responses from the local DC
*/
public class DatacenterQuorumResponseHandler<T> extends QuorumResponseHandler<T>
{
    private static final IEndpointSnitch snitch = DatabaseDescriptor.getEndpointSnitch();
  private static final String localdc = snitch.getDatacenter(FBUtilities.getLocalAddress());
    private AtomicInteger localResponses;
   
    public DatacenterQuorumResponseHandler(IResponseResolver<T> responseResolver, ConsistencyLevel consistencyLevel, String table)
    {
        super(responseResolver, consistencyLevel, table);
        localResponses = new AtomicInteger(blockfor);
    }
   
    @Override
    public void response(Message message)
    {
        responses.add(message); // we'll go ahead and resolve a reply from anyone, even if it's not from this dc

        int n;
        n = localdc.equals(snitch.getDatacenter(message.getFrom()))
                ? localResponses.decrementAndGet()
                : localResponses.get();

        if (n == 0 && responseResolver.isDataPresent(responses))
        {
            condition.signal();
        }
    }
   
    @Override
    public int determineBlockFor(ConsistencyLevel consistency_level, String table)
  {
        NetworkTopologyStrategy stategy = (NetworkTopologyStrategy) Table.open(table).replicationStrategy;
    return (stategy.getReplicationFactor(localdc) / 2) + 1;
  }
}
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