com.allanbank.mongodb.client.connection.rs

Class ReplicaSetReconnectStrategy

java.lang.Object

com.allanbank.mongodb.client.state.AbstractReconnectStrategy

com.allanbank.mongodb.client.connection.rs.ReplicaSetReconnectStrategy

All Implemented Interfaces:

ReconnectStrategy

public class ReplicaSetReconnectStrategy
extends AbstractReconnectStrategy

ReplicaSetReconnectStrategy provides a ReconnectStrategy designed for replica sets. The reconnect strategy attempts to locate the primary member of the replica set by:

1. Querying each member of the replica set for the primary server.
2. Once a primary server has been identified by a member of the replica set (the putative primary) the putative primary server is queried for the primary server.
1. If the putative primary concurs that it is the primary then the search completes and the primary server's connection is used.
2. If the putative primary does not concur then the search continues scanning each server in turn for the primary server.

API Warning:

This class is NOT part of the drivers API. This class may be mutated in incompatible ways between any two releases of the driver.

Copyright ©:

2012-2014, Allanbank Consulting, Inc., All Rights Reserved

Field Summary

Fields

Modifier and Type	Field and Description
static int	INITIAL_RECONNECT_PAUSE_TIME_MS The initial amount of time to pause waiting for a server to take over as the primary.
protected static Log	LOG The logger for the ReplicaSetReconnectStrategy.
static int	MAX_RECONNECT_PAUSE_TIME_MS The Maximum amount of time to pause waiting for a server to take over as the primary.

Fields inherited from class com.allanbank.mongodb.client.state.AbstractReconnectStrategy

myConfig, myConnectionFactory, mySelector, myState

Constructor Summary

Constructors

Constructor and Description
ReplicaSetReconnectStrategy() Creates a new ReplicaSetReconnectStrategy.

Method Summary

Methods

Modifier and Type	Method and Description
protected ConnectionInfo<Server>	checkForReply(Cluster state, Map<Server,Future<Reply>> answers, Map<Server,Connection> connections, long deadline) Checks for a reply from a server.
protected String	checkReply(Future<Reply> replyFuture, Map<Server,Connection> connections, Server server, long deadline) Extracts who the server thinks is the primary from the reply.
ReplicaSetConnection	reconnect(Connection oldConnection) Encapsulates the strategy for re-establishing the connection to the server.
ConnectionInfo<Server>	reconnectPrimary() Overridden to search for the primary server in the replica set.
protected Future<Reply>	sendIsPrimary(Map<Server,Future<Reply>> answers, Map<Server,Connection> connections, Server server, boolean isPrimary) Sends a command to the server to return what it thinks the state of the cluster is.
protected void	sleep(int sleepTime, TimeUnit units) Sleeps without throwing an exception.
protected boolean	verifyPutative(Map<Server,Future<Reply>> answers, Map<Server,Connection> connections, Server putativePrimary, long deadline) Tries to verify that the suspected primary server is in fact the primary server by asking it directly and synchronously.

Methods inherited from class com.allanbank.mongodb.client.state.AbstractReconnectStrategy

getConfig, getConnectionFactory, getSelector, getState, isConnected, setConfig, setConnectionFactory, setSelector, setState

Methods inherited from class java.lang.Object

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

Field Detail

INITIAL_RECONNECT_PAUSE_TIME_MS

public static final int INITIAL_RECONNECT_PAUSE_TIME_MS

The initial amount of time to pause waiting for a server to take over as the primary.

See Also:

Constant Field Values

MAX_RECONNECT_PAUSE_TIME_MS

public static final int MAX_RECONNECT_PAUSE_TIME_MS

The Maximum amount of time to pause waiting for a server to take over as the primary.

See Also:

Constant Field Values

LOG

protected static final Log LOG

The logger for the ReplicaSetReconnectStrategy.

Constructor Detail

ReplicaSetReconnectStrategy

public ReplicaSetReconnectStrategy()

Creates a new ReplicaSetReconnectStrategy.

Method Detail

reconnect

public ReplicaSetConnection reconnect(Connection oldConnection)

Encapsulates the strategy for re-establishing the connection to the server.

Overridden to search for the primary server in the replica set. This will only continue until the MongoClientConfiguration.getReconnectTimeout() has expired.

Parameters:

oldConnection - The connection that has become disconnected.

Returns:

The new connection to the server or null if a connection could not be created.

reconnectPrimary

public ConnectionInfo<Server> reconnectPrimary()

Overridden to search for the primary server in the replica set. This will only continue until the MongoClientConfiguration.getReconnectTimeout() has expired.

Returns:

The information for the primary connection or null if the reconnect fails.

checkForReply

protected ConnectionInfo<Server> checkForReply(Cluster state,
                                   Map<Server,Future<Reply>> answers,
                                   Map<Server,Connection> connections,
                                   long deadline)

Checks for a reply from a server. If one has been received then it tries to confirm the primary server by asking it if it thinks it is the primary server.

Parameters:

state - The state of the cluster.

answers - The pending (Future) answers from each server.

connections - The connection to each server.

deadline - The deadline for the reconnect attempt.

Returns:

The new connection if there was a reply and that server confirmed it was the primary.

checkReply

protected String checkReply(Future<Reply> replyFuture,
                Map<Server,Connection> connections,
                Server server,
                long deadline)

Extracts who the server thinks is the primary from the reply.

Parameters:

replyFuture - The future to get the reply from.

connections - The map of connections. The connection will be closed on an error.

server - The server.

deadline - The deadline for the reconnect attempt.

Returns:

The name of the server the reply indicates is the primary, null if there is no primary or any error.

sendIsPrimary

protected Future<Reply> sendIsPrimary(Map<Server,Future<Reply>> answers,
                          Map<Server,Connection> connections,
                          Server server,
                          boolean isPrimary)

Sends a command to the server to return what it thinks the state of the cluster is. This method will not re-request the information from the server if there is already an outstanding request.

Parameters:

answers - The pending (Future) answers from each server.

connections - The connection to each server.

server - The server to send the request to.

isPrimary - If true logs connection errors as warnings. Debug otherwise.

Returns:

The future reply for the request sent to the server.

sleep

protected void sleep(int sleepTime,
         TimeUnit units)

Sleeps without throwing an exception.

Parameters:

sleepTime - The amount of time to sleep.

units - The untis for the amount of time to sleep.

verifyPutative

protected boolean verifyPutative(Map<Server,Future<Reply>> answers,
                     Map<Server,Connection> connections,
                     Server putativePrimary,
                     long deadline)

Tries to verify that the suspected primary server is in fact the primary server by asking it directly and synchronously.

Parameters:

answers - The pending (Future) answers from each server.

connections - The connection to each server.

putativePrimary - The server we think is the primary.

deadline - The deadline for the reconnect attempt.

Returns:

True if the server concurs that it is the primary.