com.thinkaurelius.titan.graphdb.database.idassigner.placement

Class DefaultPlacementStrategy

java.lang.Object

com.thinkaurelius.titan.graphdb.database.idassigner.placement.DefaultPlacementStrategy

All Implemented Interfaces:

IDPlacementStrategy

public class DefaultPlacementStrategy
extends Object
implements IDPlacementStrategy

Default IDPlacementStrategy that assigns all vertices to a fixed partition configured upon construction. This strategy is used when partitioning is disabled. This strategy is not configurable.

Author:

Matthias Broecheler (me@matthiasb.com)

Constructor Summary

Constructors

Constructor and Description
DefaultPlacementStrategy()
DefaultPlacementStrategy(int partitionID)

Method Summary

Methods

Modifier and Type	Method and Description
void	exhaustedPartition(int partitionID) Called when there are no more idAuthorities left in the given partition.
int	getPartition(InternalElement element) Individually assigns an id to the given vertex or relation.
void	getPartitions(Map<InternalVertex,PartitionAssignment> vertices) Bulk assignment of idAuthorities to vertices.
void	setLocalPartitionBounds(List<PartitionIDRange> localPartitionIdRanges) If Titan is embedded, this method is used to indicate to the placement strategy which part of the partition id space is hosted locally so that vertex and edge placements can be made accordingly (i.e.
boolean	supportsBulkPlacement() Whether this placement strategy supports bulk placement.

Methods inherited from class java.lang.Object

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

Constructor Detail

DefaultPlacementStrategy

public DefaultPlacementStrategy(int partitionID)

DefaultPlacementStrategy

public DefaultPlacementStrategy()

Method Detail

getPartition

public int getPartition(InternalElement element)

Description copied from interface: IDPlacementStrategy

Individually assigns an id to the given vertex or relation.

Specified by:

getPartition in interface IDPlacementStrategy

Parameters:

element - Vertex or relation to assign id to.

Returns:

getPartitions

public void getPartitions(Map<InternalVertex,PartitionAssignment> vertices)

Description copied from interface: IDPlacementStrategy

Bulk assignment of idAuthorities to vertices.

It is expected that the passed in map contains the partition assignment after this method returns. Any initial values in the map are meaningless and to be ignored.

This is an optional operation. Check with IDPlacementStrategy.supportsBulkPlacement() first.

Specified by:

getPartitions in interface IDPlacementStrategy

Parameters:

vertices - Map containing all vertices and their partition placement.

supportsBulkPlacement

public boolean supportsBulkPlacement()

Description copied from interface: IDPlacementStrategy

Whether this placement strategy supports bulk placement. If not, then IDPlacementStrategy.getPartitions(java.util.Map) will throw UnsupportedOperationException

Specified by:

supportsBulkPlacement in interface IDPlacementStrategy

Returns:

setLocalPartitionBounds

public void setLocalPartitionBounds(List<PartitionIDRange> localPartitionIdRanges)

Description copied from interface: IDPlacementStrategy

If Titan is embedded, this method is used to indicate to the placement strategy which part of the partition id space is hosted locally so that vertex and edge placements can be made accordingly (i.e. preferring to assign partitions in the local ranges so that the data is hosted locally which is often faster).

This method can be called at any time while Titan is running. It is typically called right after construction and when the id space is redistributed.

Depending on the storage backend one or multiple ranges of partition ids may be given. However, this list is never emtpy.

Specified by:

setLocalPartitionBounds in interface IDPlacementStrategy

Parameters:

localPartitionIdRanges - List of PartitionIDRanges correspondinging to the locally hosted partitions

exhaustedPartition

public void exhaustedPartition(int partitionID)

Description copied from interface: IDPlacementStrategy

Called when there are no more idAuthorities left in the given partition. It is expected that the placement strategy will no longer use said partition in its placement suggestions.

Specified by:

exhaustedPartition in interface IDPlacementStrategy

Parameters:

partitionID - Id of the partition that has been exhausted.