Package org.eclipse.persistence.descriptors.partitioning

Class RoundRobinPartitioningPolicy

java.lang.Object

org.eclipse.persistence.descriptors.partitioning.PartitioningPolicy

org.eclipse.persistence.descriptors.partitioning.ReplicationPartitioningPolicy

org.eclipse.persistence.descriptors.partitioning.RoundRobinPartitioningPolicy

All Implemented Interfaces:

java.io.Serializable

public class RoundRobinPartitioningPolicy
extends ReplicationPartitioningPolicy

PUBLIC: RoundRobinPartitioningPolicy sends requests in a round robin fashion to the set of connection pools. It is for load-balancing read queries across a cluster of database machines. It requires that the full database be replicated on each machine, so does not support partitioning. The data should either be read-only, or writes should be replicated on the database.

See Also:

Serialized Form

Author:

James Sutherland

Since:

EclipseLink 2.2

Field Summary

Fields

Modifier and Type	Field	Description
protected int	currentIndex
protected boolean	replicateWrites

Fields inherited from class org.eclipse.persistence.descriptors.partitioning.ReplicationPartitioningPolicy

connectionPools

Fields inherited from class org.eclipse.persistence.descriptors.partitioning.PartitioningPolicy

name

Constructor Summary

Constructors

Constructor	Description
RoundRobinPartitioningPolicy()
RoundRobinPartitioningPolicy(boolean replicateWrites)
RoundRobinPartitioningPolicy(java.lang.String... pools)
RoundRobinPartitioningPolicy(java.util.List<java.lang.String> pools)

Method Summary

Modifier and Type	Method	Description
java.util.List<org.eclipse.persistence.internal.databaseaccess.Accessor>	getConnectionsForQuery(org.eclipse.persistence.internal.sessions.AbstractSession session, DatabaseQuery query, org.eclipse.persistence.internal.sessions.AbstractRecord arguments)	INTERNAL: Get a connection from one of the pools in a round robin rotation fashion.
boolean	getReplicateWrites()	PUBLIC: Return if write queries should be replicated.
org.eclipse.persistence.internal.databaseaccess.Accessor	nextAccessor(ServerSession session, DatabaseQuery query)	INTERNAL: Return the next connection accessor.
int	nextIndex()	INTERNAL: Return the next pool index to use.
void	setReplicateWrites(boolean replicateWrites)	PUBLIC: Set if write queries should be replicated.

Methods inherited from class org.eclipse.persistence.descriptors.partitioning.ReplicationPartitioningPolicy

addConnectionPool, getConnectionPools, initialize, setConnectionPools

Methods inherited from class org.eclipse.persistence.descriptors.partitioning.PartitioningPolicy

acquireAccessor, convertClassNamesToClasses, getAccessor, getName, partitionPersist, setName

Methods inherited from class java.lang.Object

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

Field Detail

currentIndex

protected volatile int currentIndex

replicateWrites

protected boolean replicateWrites

Constructor Detail

RoundRobinPartitioningPolicy

public RoundRobinPartitioningPolicy()

RoundRobinPartitioningPolicy

public RoundRobinPartitioningPolicy(boolean replicateWrites)

RoundRobinPartitioningPolicy

public RoundRobinPartitioningPolicy(java.lang.String... pools)

RoundRobinPartitioningPolicy

public RoundRobinPartitioningPolicy(java.util.List<java.lang.String> pools)

Method Detail

getReplicateWrites

public boolean getReplicateWrites()

PUBLIC: Return if write queries should be replicated. This allows for a set of database to be written to and kept in synch, and have reads load-balanced across the databases.

setReplicateWrites

public void setReplicateWrites(boolean replicateWrites)

PUBLIC: Set if write queries should be replicated. This allows for a set of database to be written to and kept in synch, and have reads load-balanced across the databases.

getConnectionsForQuery

public java.util.List<org.eclipse.persistence.internal.databaseaccess.Accessor> getConnectionsForQuery(org.eclipse.persistence.internal.sessions.AbstractSession session,
                                                                                                       DatabaseQuery query,
                                                                                                       org.eclipse.persistence.internal.sessions.AbstractRecord arguments)

INTERNAL: Get a connection from one of the pools in a round robin rotation fashion.

Overrides:

getConnectionsForQuery in class ReplicationPartitioningPolicy

nextIndex

public int nextIndex()

INTERNAL: Return the next pool index to use.

nextAccessor

public org.eclipse.persistence.internal.databaseaccess.Accessor nextAccessor(ServerSession session,
                                                                             DatabaseQuery query)

INTERNAL: Return the next connection accessor.