/**
* 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.
*/
package org.apache.cassandra.service;
import java.io.IOException;
import java.net.InetAddress;
import java.util.Collection;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.cassandra.config.DatabaseDescriptor;
import org.apache.cassandra.db.ReadResponse;
import org.apache.cassandra.db.Table;
import org.apache.cassandra.net.IAsyncCallback;
import org.apache.cassandra.net.Message;
import org.apache.cassandra.net.MessagingService;
import org.apache.cassandra.thrift.ConsistencyLevel;
import org.apache.cassandra.thrift.UnavailableException;
import org.apache.cassandra.utils.SimpleCondition;
public class ReadCallback<T> implements IAsyncCallback
{
protected static final Logger logger = LoggerFactory.getLogger( ReadCallback.class );
public final IResponseResolver<T> resolver;
protected final SimpleCondition condition = new SimpleCondition();
private final long startTime;
protected final int blockfor;
/**
* Constructor when response count has to be calculated and blocked for.
*/
public ReadCallback(IResponseResolver<T> resolver, ConsistencyLevel consistencyLevel, String table)
{
this.blockfor = determineBlockFor(consistencyLevel, table);
this.resolver = resolver;
this.startTime = System.currentTimeMillis();
logger.debug("ReadCallback blocking for {} responses", blockfor);
}
public T get() throws TimeoutException, DigestMismatchException, IOException
{
long timeout = DatabaseDescriptor.getRpcTimeout() - (System.currentTimeMillis() - startTime);
boolean success;
try
{
success = condition.await(timeout, TimeUnit.MILLISECONDS);
}
catch (InterruptedException ex)
{
throw new AssertionError(ex);
}
if (!success)
{
StringBuilder sb = new StringBuilder("");
for (Message message : resolver.getMessages())
sb.append(message.getFrom()).append(", ");
throw new TimeoutException("Operation timed out - received only " + resolver.getMessageCount() + " responses from " + sb.toString() + " .");
}
return blockfor == 1 ? resolver.getData() : resolver.resolve();
}
public void response(Message message)
{
resolver.preprocess(message);
if (resolver.getMessageCount() < blockfor)
return;
if (resolver.isDataPresent())
condition.signal();
}
public void response(ReadResponse result)
{
((ReadResponseResolver) resolver).injectPreProcessed(result);
if (resolver.getMessageCount() < blockfor)
return;
if (resolver.isDataPresent())
condition.signal();
}
public int determineBlockFor(ConsistencyLevel consistencyLevel, String table)
{
switch (consistencyLevel)
{
case ONE:
case ANY:
return 1;
case QUORUM:
return (Table.open(table).getReplicationStrategy().getReplicationFactor() / 2) + 1;
case ALL:
return Table.open(table).getReplicationStrategy().getReplicationFactor();
default:
throw new UnsupportedOperationException("invalid consistency level: " + consistencyLevel);
}
}
public void assureSufficientLiveNodes(Collection<InetAddress> endpoints) throws UnavailableException
{
if (endpoints.size() < blockfor)
throw new UnavailableException();
}
}