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
* specific language governing permissions and limitations
* under the License.
*
*/
import java.net.InetAddress;
import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;
import org.apache.cassandra.config.DatabaseDescriptor;
import org.apache.cassandra.db.ReadResponse;
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.thrift.UnavailableException;
import org.apache.cassandra.utils.FBUtilities;
/**
* Datacenter Quorum response handler blocks for a quorum of responses from the local DC
*/
public class DatacenterReadCallback<T> extends ReadCallback<T>
{
private static final IEndpointSnitch snitch = DatabaseDescriptor.getEndpointSnitch();
private static final String localdc = snitch.getDatacenter(FBUtilities.getLocalAddress());
private AtomicInteger localResponses;
public DatacenterReadCallback(IResponseResolver resolver, ConsistencyLevel consistencyLevel, IReadCommand command, List<InetAddress> endpoints)
{
super(resolver, consistencyLevel, command, endpoints);
localResponses = new AtomicInteger(blockfor);
}
@Override
public void response(Message message)
{
resolver.preprocess(message);
int n = localdc.equals(snitch.getDatacenter(message.getFrom()))
? localResponses.decrementAndGet()
: localResponses.get();
if (n == 0 && resolver.isDataPresent())
{
condition.signal();
}
}
@Override
public void response(ReadResponse result)
{
((RowDigestResolver) resolver).injectPreProcessed(result);
int n = localResponses.decrementAndGet();
if (n == 0 && resolver.isDataPresent())
{
condition.signal();
}
maybeResolveForRepair();
}
@Override
public int determineBlockFor(ConsistencyLevel consistency_level, String table)
{
NetworkTopologyStrategy stategy = (NetworkTopologyStrategy) Table.open(table).getReplicationStrategy();
return (stategy.getReplicationFactor(localdc) / 2) + 1;
}
@Override
public void assureSufficientLiveNodes() throws UnavailableException
{
int localEndpoints = 0;
for (InetAddress endpoint : endpoints)
{
if (localdc.equals(snitch.getDatacenter(endpoint)))
localEndpoints++;
}
if(localEndpoints < blockfor)
throw new UnavailableException();
}
}