Package org.eclipse.persistence.descriptors.partitioning

Class HashPartitioningPolicy

java.lang.Object

org.eclipse.persistence.descriptors.partitioning.PartitioningPolicy

org.eclipse.persistence.descriptors.partitioning.FieldPartitioningPolicy

org.eclipse.persistence.descriptors.partitioning.HashPartitioningPolicy

All Implemented Interfaces:

Serializable

public class HashPartitioningPolicy
extends FieldPartitioningPolicy

PUBLIC: HashPartitioningPolicy partitions access to a database cluster by the hash of a field value from the object, such as the object's location, or tenant. The hash indexes into the list of connection pools. All write or read request for objects with that hash value are sent to the server. If a query does not include the field as a parameter, then it can either be sent to all servers and unioned, or left to the session's default behavior.

Since:

EclipseLink 2.2

Author:

James Sutherland

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
protected List<String>	connectionPools

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

partitionField, unionUnpartitionableQueries

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

name

Constructor Summary

Constructors

Constructor	Description
HashPartitioningPolicy()
HashPartitioningPolicy(String partitionField)
HashPartitioningPolicy(String partitionField, boolean unionUnpartitionableQueries)

Method Summary

Modifier and Type	Method	Description
void	addConnectionPool(String connectionPool)	PUBLIC: Add the connection pool name to the list of pools to rotate queries through.
List<String>	getConnectionPools()	PUBLIC: Return the list of connection pool names to replicate queries to.
List<Accessor>	getConnectionsForQuery(AbstractSession session, DatabaseQuery query, AbstractRecord arguments)	INTERNAL: Get a connection from one of the pools in a round robin rotation fashion.
void	initialize(AbstractSession session)	INTERNAL: Default the connection pools to all pools if unset.
void	partitionPersist(AbstractSession session, Object object, ClassDescriptor descriptor)	INTERNAL: Allow for the persist call to assign the partition.
void	setConnectionPools(List<String> connectionPools)	PUBLIC: Set the list of connection pool names to replicate queries to.

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

extractPartitionValueForPersist, getPartitionField, getPartitionFieldName, getUnionUnpartitionableQueries, setPartitionField, setPartitionField, setUnionUnpartitionableQueries

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

acquireAccessor, convertClassNamesToClasses, getAccessor, getName, setName

Methods inherited from class java.lang.Object

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

Field Detail

connectionPools

protected List<String> connectionPools

Constructor Detail

HashPartitioningPolicy

public HashPartitioningPolicy()

HashPartitioningPolicy

public HashPartitioningPolicy(String partitionField)

HashPartitioningPolicy

public HashPartitioningPolicy(String partitionField,
                              boolean unionUnpartitionableQueries)

Method Detail

initialize

public void initialize(AbstractSession session)

INTERNAL: Default the connection pools to all pools if unset.

Overrides:

initialize in class PartitioningPolicy

getConnectionPools

public List<String> getConnectionPools()

PUBLIC: Return the list of connection pool names to replicate queries to.

setConnectionPools

public void setConnectionPools(List<String> connectionPools)

PUBLIC: Set the list of connection pool names to replicate queries to. A connection pool with the same name must be defined on the ServerSession.

addConnectionPool

public void addConnectionPool(String connectionPool)

PUBLIC: Add the connection pool name to the list of pools to rotate queries through.

getConnectionsForQuery

public List<Accessor> getConnectionsForQuery(AbstractSession session,
                                             DatabaseQuery query,
                                             AbstractRecord arguments)

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

Specified by:

getConnectionsForQuery in class PartitioningPolicy

partitionPersist

public void partitionPersist(AbstractSession session,
                             Object object,
                             ClassDescriptor descriptor)

INTERNAL: Allow for the persist call to assign the partition.

Overrides:

partitionPersist in class PartitioningPolicy