/**
* 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.client;
import java.io.IOException;
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.nio.ByteBuffer;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import com.google.common.collect.ArrayListMultimap;
import com.google.common.collect.Multimap;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.cassandra.dht.IPartitioner;
import org.apache.cassandra.dht.Range;
import org.apache.cassandra.dht.Token;
import org.apache.cassandra.thrift.Cassandra;
import org.apache.cassandra.thrift.InvalidRequestException;
import org.apache.cassandra.thrift.TokenRange;
import org.apache.thrift.TException;
import org.apache.cassandra.thrift.TBinaryProtocol;
import org.apache.thrift.transport.TFramedTransport;
import org.apache.thrift.transport.TSocket;
/**
* A class for caching the ring map at the client. For usage example, see
* test/unit/org.apache.cassandra.client.TestRingCache.java.
* TODO: doing a naive linear search of the token map
*/
public class RingCache
{
final private static Logger logger_ = LoggerFactory.getLogger(RingCache.class);
private final Set<String> seeds_ = new HashSet<String>();
private final int port_;
private final IPartitioner partitioner_;
private final String keyspace;
private Multimap<Range, InetAddress> rangeMap;
public RingCache(String keyspace, IPartitioner partitioner, String addresses, int port) throws IOException
{
for (String seed : addresses.split(","))
seeds_.add(seed);
this.port_ = port;
this.keyspace = keyspace;
this.partitioner_ = partitioner;
refreshEndpointMap();
}
public void refreshEndpointMap()
{
for (String seed : seeds_)
{
try
{
TSocket socket = new TSocket(seed, port_);
TBinaryProtocol binaryProtocol = new TBinaryProtocol(new TFramedTransport(socket));
Cassandra.Client client = new Cassandra.Client(binaryProtocol);
socket.open();
List<TokenRange> ring = client.describe_ring(keyspace);
rangeMap = ArrayListMultimap.create();
for (TokenRange range : ring)
{
Token<?> left = partitioner_.getTokenFactory().fromString(range.start_token);
Token<?> right = partitioner_.getTokenFactory().fromString(range.end_token);
Range r = new Range(left, right, partitioner_);
for (String host : range.endpoints)
{
try
{
rangeMap.put(r, InetAddress.getByName(host));
}
catch (UnknownHostException e)
{
throw new AssertionError(e); // host strings are IPs
}
}
}
break;
}
catch (InvalidRequestException e)
{
throw new RuntimeException(e);
}
catch (TException e)
{
/* let the Exception go and try another seed. log this though */
logger_.debug("Error contacting seed " + seed + " " + e.getMessage());
}
}
}
/** ListMultimap promises to return a List for get(K) */
@SuppressWarnings(value="unchecked")
public List<InetAddress> getEndpoint(Range range)
{
return (List<InetAddress>) rangeMap.get(range);
}
public List<InetAddress> getEndpoint(ByteBuffer key)
{
return getEndpoint(getRange(key));
}
public Range getRange(ByteBuffer key)
{
// TODO: naive linear search of the token map
Token<?> t = partitioner_.getToken(key);
for (Range range : rangeMap.keySet())
if (range.contains(t))
return range;
throw new RuntimeException("Invalid token information returned by describe_ring: " + rangeMap);
}
}