org.cloudgraph.hbase.graph

Class GraphSliceAssembler

java.lang.Object

org.cloudgraph.hbase.graph.DefaultAssembler

org.cloudgraph.hbase.graph.DistributedAssembler

org.cloudgraph.hbase.graph.GraphSliceAssembler

All Implemented Interfaces:

HBaseGraphAssembler, org.plasma.sdo.access.DataGraphAssembler

public class GraphSliceAssembler
extends DistributedAssembler

Assembles a data graph where one or more collections may be "sliced" based on path predicates within the "selection graph".

Edges within a collection are "recognized" as members of a slice based on a binary expression syntax tree assembled from the path predicate describing the slice. While a path predicate may be quite complex resulting in any number of logical, relational or wildcard binary expressions, a single slice syntax tree is used to evaluate any number of edges within a collection. Where edge opposite graph nodes are found within the current row, an edge recognizer is used, but where edge opposite graph nodes are found "outside" the current row, a graph recognizer is used.

Since every column key in HBase must be unique, and a data graph may contain any number of nodes, a column key factory is used both to persist as well as re-constitute a graph. A minimal amount of "state" information is therefore stored with each graph which maps user readable sequence numbers (which are used in column keys) to UUID values. The nodes of the resulting data graph are re-created with the original UUID values.

Since:

0.5.1

Author:

Scott Cinnamond

See Also:

LocalEdgeRecognizerSyntaxTreeAssembler, LocalEdgeRecognizerContext, GraphRecognizerSyntaxTreeAssembler, GraphRecognizerContext, GraphSliceSupport, StatefullColumnKeyFactory

Field Summary

Fields inherited from class org.cloudgraph.hbase.graph.DistributedAssembler

distributedReader

Fields inherited from class org.cloudgraph.hbase.graph.DefaultAssembler

graph, keyFactories, root, rootTableReader, rootType, selection, snapshotDate

Constructor Summary

Constructors

Constructor and Description
GraphSliceAssembler(org.plasma.sdo.PlasmaType rootType, StoreMappingContext mappingContext, org.plasma.query.collector.Selection selection, DistributedReader distributedReader, Timestamp snapshotDate)

Method Summary

Modifier and Type	Method and Description
protected void	assemble(org.plasma.sdo.PlasmaDataObject target, long targetSequence, EdgeReader sourceCollection, org.plasma.sdo.PlasmaDataObject source, org.plasma.sdo.PlasmaProperty sourceProperty, RowReader rowReader, int level) Populates the given data object target, recursively fetching data for and linking related data objects which make up the resulting directed graph.

Methods inherited from class org.cloudgraph.hbase.graph.DistributedAssembler

assemble, assembleEdge, assembleExternalEdge, clear

Methods inherited from class org.cloudgraph.hbase.graph.DefaultAssembler

assembleData, assembleUUID, createChild, createChild, createChild, createRoot, fetchGraph, fetchRootType, fetchRootUUID, fetchType, fetchUUID, findMetaDataColumnValue, findMetaDataColumnValue, findRootType, findRootUUID, getDataColumnValue, getDataColumnValue, getDataGraph, getKeyFactory, getMetaDataColumnValue, getMetaDataColumnValue, getProperties, getProperties, link

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.plasma.sdo.access.DataGraphAssembler

getDataGraph

Constructor Detail

GraphSliceAssembler

public GraphSliceAssembler(org.plasma.sdo.PlasmaType rootType,
                           StoreMappingContext mappingContext,
                           org.plasma.query.collector.Selection selection,
                           DistributedReader distributedReader,
                           Timestamp snapshotDate)

Method Detail

assemble

protected void assemble(org.plasma.sdo.PlasmaDataObject target,
                        long targetSequence,
                        EdgeReader sourceCollection,
                        org.plasma.sdo.PlasmaDataObject source,
                        org.plasma.sdo.PlasmaProperty sourceProperty,
                        RowReader rowReader,
                        int level)
                 throws IOException

Description copied from class: DistributedAssembler

Populates the given data object target, recursively fetching data for and linking related data objects which make up the resulting directed graph.

Specified by:

assemble in class DistributedAssembler

targetSequence - the current data object sequence

source - the source or parent data object

sourceProperty - the source (reference) property

rowReader - the current row reader

level - the current graph level

Throws:

IOException - if a remote or network exception occurs.