org.apache.cassandra.service.QueryState Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of cassandra-all Show documentation
Show all versions of cassandra-all Show documentation
The Apache Cassandra Project develops a highly scalable second-generation distributed database, bringing together Dynamo's fully distributed design and Bigtable's ColumnFamily-based data model.
/*
* 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 org.apache.cassandra.utils.FBUtilities;
/**
* Primarily used as a recorder for server-generated timestamps (timestamp, in microseconds, and nowInSeconds - in, well, seconds).
*
* The goal is to be able to use a single consistent server-generated value for both timestamps across the whole request,
* and later be able to inspect QueryState for the generated values - for logging or other purposes.
*/
public class QueryState
{
private final ClientState clientState;
private long timestamp = Long.MIN_VALUE;
private long nowInSeconds = Integer.MIN_VALUE;
public QueryState(ClientState clientState)
{
this.clientState = clientState;
}
public QueryState(ClientState clientState, long timestamp, long nowInSeconds)
{
this(clientState);
this.timestamp = timestamp;
this.nowInSeconds = nowInSeconds;
}
/**
* @return a QueryState object for internal C* calls (not limited by any kind of auth).
*/
public static QueryState forInternalCalls()
{
return new QueryState(ClientState.forInternalCalls());
}
/**
* Generate, cache, and record a timestamp value on the server-side.
*
* Used in reads for all live and expiring cells, and all kinds of deletion infos.
*
* Shouldn't be used directly. {@link org.apache.cassandra.cql3.QueryOptions#getTimestamp(QueryState)} should be used
* by all consumers.
*
* @return server-generated, recorded timestamp in seconds
*/
public long getTimestamp()
{
if (timestamp == Long.MIN_VALUE)
timestamp = ClientState.getTimestamp();
return timestamp;
}
/**
* Generate, cache, and record a nowInSeconds value on the server-side.
*
* In writes is used for calculating localDeletionTime for tombstones and expiring cells and other deletion infos.
* In reads used to determine liveness of expiring cells and rows.
*
* Shouldn't be used directly. {@link org.apache.cassandra.cql3.QueryOptions#getNowInSeconds(QueryState)} should be used
* by all consumers.
*
* @return server-generated, recorded timestamp in seconds
*/
public long getNowInSeconds()
{
if (nowInSeconds == Integer.MIN_VALUE)
nowInSeconds = FBUtilities.nowInSeconds();
return nowInSeconds;
}
/**
* @return server-generated timestamp value, if one had been requested, or Long.MIN_VALUE otherwise
*/
public long generatedTimestamp()
{
return timestamp;
}
/**
* @return server-generated nowInSeconds value, if one had been requested, or Integer.MIN_VALUE otherwise
*/
public long generatedNowInSeconds()
{
return nowInSeconds;
}
public ClientState getClientState()
{
return clientState;
}
public InetAddress getClientAddress()
{
return clientState.getClientAddress();
}
}