Module org.apache.jena.core

Package org.apache.jena.mem2

Class GraphMem2Fast

java.lang.Object

org.apache.jena.graph.impl.GraphBase

org.apache.jena.mem.GraphMemBase

org.apache.jena.mem2.GraphMem2

org.apache.jena.mem2.GraphMem2Fast

All Implemented Interfaces:

org.apache.jena.atlas.lib.Copyable<GraphMem2>, Graph, GraphWithPerform

public class GraphMem2Fast
extends GraphMem2

A graph that stores triples in memory. This class is not thread-safe.

Purpose: GraphMem2Fast is a strong candidate for becoming the new default in-memory graph in the upcoming Jena 5, thanks to its improved performance and relatively minor increase in memory usage.

Faster than GraphMem2Legacy (specially Graph#add, Graph#find and Graph#stream) Removing triples is a bit slower than GraphMem2Legacy. Memory consumption is about 6-35% higher than GraphMem2Legacy Maps and sets are based on FastHashBase Benefits from multiple small optimizations. (see: FastTripleStore)

The heritage of GraphMem: - Also uses 3 hash-maps indexed by subjects, predicates, and objects - Values of the maps also switch from arrays to hash sets for the triples

Field Summary

Fields inherited from class org.apache.jena.graph.impl.GraphBase

TOSTRING_TRIPLE_BASE, TOSTRING_TRIPLE_LIMIT

Fields inherited from interface org.apache.jena.graph.Graph

emptyGraph

Constructor Summary

Constructors

Constructor	Description
GraphMem2Fast()

Method Summary

Modifier and Type	Method	Description
GraphMem2Fast	copy()	Creates a copy of this graph.

Methods inherited from class org.apache.jena.mem2.GraphMem2

clear, destroy, getCapabilities, graphBaseContains, graphBaseFind, graphBaseSize, performAdd, performDelete, stream, stream

Methods inherited from class org.apache.jena.mem.GraphMemBase

close, openAgain

Methods inherited from class org.apache.jena.graph.impl.GraphBase

add, contains, contains, delete, dependsOn, find, find, forTestingOnly_graphBaseFind, getEventManager, getPrefixMapping, getTransactionHandler, isClosed, isEmpty, isIsomorphicWith, notifyAdd, notifyDelete, remove, size, toString, toString

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.apache.jena.graph.Graph

add, add, close, contains, contains, delete, delete, dependsOn, find, find, find, getEventManager, getPrefixMapping, getTransactionHandler, isClosed, isEmpty, isIsomorphicWith, remove, size, sizeLong

Constructor Details

GraphMem2Fast

public GraphMem2Fast()

Method Details

copy

public GraphMem2Fast copy()

Description copied from class: GraphMem2

Creates a copy of this graph. Since the triples and nodes are immutable, the copy contains the same triples and nodes as this graph. Modifications to the copy will not affect this graph.

Specified by:

copy in interface org.apache.jena.atlas.lib.Copyable<GraphMem2>

Overrides:

copy in class GraphMem2

Returns:

independent copy of the current graph