Module org.apache.jena.core

Package org.apache.jena.mem

Class GraphMemFast

java.lang.Object

org.apache.jena.graph.impl.GraphBase

org.apache.jena.mem.GraphMem

org.apache.jena.mem.GraphMemFast

All Implemented Interfaces:

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

public class GraphMemFast
extends GraphMem

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

Compared to GraphMemLegacy:

• Faster than GraphMemLegacy (specially Graph#add, Graph#find and Graph#stream)
• Removing triples is a bit slower than GraphMemLegacy.
• Memory consumption is about 6-35% higher than GraphMemLegacy
• 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
GraphMemFast()

Method Summary

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

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

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

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

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

Constructor Details

GraphMemFast

public GraphMemFast()

Method Details

copy

public GraphMemFast copy()

Description copied from class: GraphMem

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<GraphMem>

Overrides:

copy in class GraphMem

Returns:

independent copy of the current graph