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/*
* 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.hadoop.cql3;
import com.datastax.driver.core.Host;
import com.datastax.driver.core.Metadata;
import com.datastax.driver.core.Token;
import com.datastax.driver.core.TokenRange;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Objects;
public class CqlClientHelper
{
private CqlClientHelper()
{
}
public static Map> getLocalPrimaryRangeForDC(String keyspace, Metadata metadata, String targetDC)
{
Objects.requireNonNull(keyspace, "keyspace");
Objects.requireNonNull(metadata, "metadata");
Objects.requireNonNull(targetDC, "targetDC");
// In 2.1 the logic was to have a set of nodes used as a seed, they were used to query
// client.describe_local_ring(keyspace) -> List; this should include all nodes in the local dc.
// TokenRange contained the endpoints in order, so .endpoints.get(0) is the primary owner
// Client does not have a similar API, instead it returns Set. To replicate this we first need
// to compute the primary owners, then add in the replicas
List tokens = new ArrayList<>();
Map tokenToHost = new HashMap<>();
for (Host host : metadata.getAllHosts())
{
if (!targetDC.equals(host.getDatacenter()))
continue;
for (Token token : host.getTokens())
{
Host previous = tokenToHost.putIfAbsent(token, host);
if (previous != null)
throw new IllegalStateException("Two hosts share the same token; hosts " + host.getHostId() + ":"
+ host.getTokens() + ", " + previous.getHostId() + ":" + previous.getTokens());
tokens.add(token);
}
}
Collections.sort(tokens);
Map> rangeToReplicas = new HashMap<>();
// The first token in the ring uses the last token as its 'start', handle this here to simplify the loop
Token start = tokens.get(tokens.size() - 1);
Token end = tokens.get(0);
addRange(keyspace, metadata, tokenToHost, rangeToReplicas, start, end);
for (int i = 1; i < tokens.size(); i++)
{
start = tokens.get(i - 1);
end = tokens.get(i);
addRange(keyspace, metadata, tokenToHost, rangeToReplicas, start, end);
}
return rangeToReplicas;
}
private static void addRange(String keyspace,
Metadata metadata,
Map tokenToHost,
Map> rangeToReplicas,
Token start, Token end)
{
Host host = tokenToHost.get(end);
String dc = host.getDatacenter();
TokenRange range = metadata.newTokenRange(start, end);
List replicas = new ArrayList<>();
replicas.add(host);
// get all the replicas for the specific DC
for (Host replica : metadata.getReplicas(keyspace, range))
{
if (dc.equals(replica.getDatacenter()) && !host.equals(replica))
replicas.add(replica);
}
List previous = rangeToReplicas.put(range, replicas);
if (previous != null)
throw new IllegalStateException("Two hosts (" + host + ", " + previous + ") map to the same token range: " + range);
}
}
