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A fork of the Apache Cassandra Project ready to embed Elasticsearch.
/*
* 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.net.InetAddress;
import java.util.UUID;
import java.util.concurrent.ThreadLocalRandom;
import org.apache.cassandra.tracing.Tracing;
/**
* Represents the state related to a given query.
*/
public class QueryState
{
private final ClientState clientState;
private volatile UUID preparedTracingSession;
public QueryState(ClientState clientState)
{
this.clientState = clientState;
}
/**
* @return a QueryState object for internal C* calls (not limited by any kind of auth).
*/
public static QueryState forInternalCalls()
{
return new QueryState(ClientState.forInternalCalls());
}
public ClientState getClientState()
{
return clientState;
}
/**
* This clock guarantees that updates for the same QueryState will be ordered
* in the sequence seen, even if multiple updates happen in the same millisecond.
*/
public long getTimestamp()
{
return clientState.getTimestamp();
}
public boolean traceNextQuery()
{
if (preparedTracingSession != null)
{
return true;
}
double traceProbability = StorageService.instance.getTraceProbability();
return traceProbability != 0 && ThreadLocalRandom.current().nextDouble() < traceProbability;
}
public void prepareTracingSession(UUID sessionId)
{
this.preparedTracingSession = sessionId;
}
public void createTracingSession()
{
UUID session = this.preparedTracingSession;
if (session == null)
{
Tracing.instance.newSession();
}
else
{
Tracing.instance.newSession(session);
this.preparedTracingSession = null;
}
}
public InetAddress getClientAddress()
{
return clientState.isInternal
? null
: clientState.getRemoteAddress().getAddress();
}
}