Package org.apache.jackrabbit.oak.index.indexer.document.flatfile.pipelined

Class PipelinedMongoServerSelector

java.lang.Object

org.apache.jackrabbit.oak.index.indexer.document.flatfile.pipelined.PipelinedMongoServerSelector

All Implemented Interfaces:

com.mongodb.event.ClusterListener, com.mongodb.selector.ServerSelector, EventListener

public class PipelinedMongoServerSelector
extends Object
implements com.mongodb.selector.ServerSelector, com.mongodb.event.ClusterListener

Selects a Mongo server that is available for a new connection. This policy is used by PipelinedMongoDownloadTask, the goal being to spread the two connections between the secondaries and avoid downloading from the primary. The policy tries to ensure the following:

- Establish new connections only to secondaries. - Do not establish more than one connection to a secondary. - If there is a connection to a secondary and that secondary is promoted to primary, the thread should disconnect from the primary and reconnect to a secondary.

This class uses the thread id of the caller to distribute the connections, that is, it assumes that there are two threads downloading from Mongo and each thread should be sent to a different secondary. If a thread calls several times the selection logic, it will receive always the same server. The thread id is used to identify the calling thread.

Constructor Summary

Constructors

Constructor	Description
PipelinedMongoServerSelector(String threadNamePrefix)

Method Summary

Modifier and Type	Method	Description
boolean	atLeastOneConnectionActive()	Returns true if there is at least one connection active.
void	clusterClosed(com.mongodb.event.ClusterClosedEvent event)
void	clusterDescriptionChanged(com.mongodb.event.ClusterDescriptionChangedEvent event)
void	clusterOpening(com.mongodb.event.ClusterOpeningEvent event)
boolean	isConnectedToPrimary()	Returns true if the current thread is connected to the primary.
List<com.mongodb.connection.ServerDescription>	select(com.mongodb.connection.ClusterDescription clusterDescription)
void	threadFinished()	Called by the downloader thread when it finishes downloading.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

PipelinedMongoServerSelector

public PipelinedMongoServerSelector(String threadNamePrefix)

Parameters:

threadNamePrefix - Threads that start with this prefix will be assigned only to secondary server. Other threads will be assigned all servers available.

Method Detail

select

public List<com.mongodb.connection.ServerDescription> select(com.mongodb.connection.ClusterDescription clusterDescription)

Specified by:

select in interface com.mongodb.selector.ServerSelector

clusterOpening

public void clusterOpening(com.mongodb.event.ClusterOpeningEvent event)

Specified by:

clusterOpening in interface com.mongodb.event.ClusterListener

clusterClosed

public void clusterClosed(com.mongodb.event.ClusterClosedEvent event)

Specified by:

clusterClosed in interface com.mongodb.event.ClusterListener

clusterDescriptionChanged

public void clusterDescriptionChanged(com.mongodb.event.ClusterDescriptionChangedEvent event)

Specified by:

clusterDescriptionChanged in interface com.mongodb.event.ClusterListener

isConnectedToPrimary

public boolean isConnectedToPrimary()

Returns true if the current thread is connected to the primary.

atLeastOneConnectionActive

public boolean atLeastOneConnectionActive()

Returns true if there is at least one connection active.

threadFinished

public void threadFinished()

Called by the downloader thread when it finishes downloading. This method removes the thread from the list of active threads.