org.apache.jena.graph.impl

Class GraphBase

java.lang.Object

org.apache.jena.graph.impl.GraphBase

All Implemented Interfaces:

Graph, GraphWithPerform

Direct Known Subclasses:

BaseInfGraph, CollectionGraph, CompositionBase, GraphMemBase

public abstract class GraphBase
extends Object
implements GraphWithPerform

GraphBase is an implementation of Graph that provides some convenient base functionality for Graph implementations.

Subtypes of GraphBase must provide performAdd(Triple), performDelete(Triple), graphBaseFind(TripleMatch,TripleAction), and graphBaseSize(). GraphBase provides default implementations of the other methods, including the other finds (on top of that one), a simple-minded prepare, and contains. GraphBase also handles the event-listening and registration interfaces.

When a GraphBase is closed, future operations on it may throw an exception.

Field Summary

Fields

Modifier and Type	Field and Description
static int	TOSTRING_TRIPLE_BASE toString will not cut off up to this number of triples.
static int	TOSTRING_TRIPLE_LIMIT toString will not output more than this number of triples.

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

emptyGraph

Constructor Summary

Constructors

Constructor and Description
GraphBase() Initialise this graph as one with reification style Minimal.

Method Summary

Modifier and Type	Method and Description
void	add(Triple t) Add a triple, and notify the event manager.
void	clear() Remove all the statements from this graph.
void	close() Close this graph.
boolean	contains(Node s, Node p, Node o) Answer true if this graph contains (s, p, o); this canonical implementation cannot be over-ridden.
boolean	contains(Triple t) Answer true iff t is in the graph as revealed by find(t) being non-empty.
void	delete(Triple t) Delete a triple, and notify the event manager.
boolean	dependsOn(Graph other) Default implementation answers true iff this graph is the same graph as the argument graph.
ExtendedIterator<Triple>	find(Node s, Node p, Node o) Returns an iterator over Triples matching a pattern.
ExtendedIterator<Triple>	find(Triple m) Returns an iterator over all the Triples that match the triple pattern.
ExtendedIterator<Triple>	forTestingOnly_graphBaseFind(Triple t)
Capabilities	getCapabilities() Answer the capabilities of this graph; the default is an AllCapabilities object (the same one each time, not that it matters - Capabilities should be immutable).
GraphEventManager	getEventManager() Answer the event manager for this graph; allocate a new one if required.
PrefixMapping	getPrefixMapping() Answer the PrefixMapping object for this graph, the same one each time.
GraphStatisticsHandler	getStatisticsHandler() Deprecated.
TransactionHandler	getTransactionHandler() Answer a transaction handler bound to this graph.
boolean	isClosed() Answer true iff .close() has been called on this Graph.
boolean	isEmpty() Answer true iff this graph contains no triples (hidden reification quads do not count).
boolean	isIsomorphicWith(Graph g) Answer true iff this graph is isomorphic to g according to the algorithm (indeed, method) in GraphMatcher.
void	notifyAdd(Triple t) Tell the event manager that the triple t has been added to the graph.
void	notifyDelete(Triple t) Tell the event manager that the triple t has been deleted from the graph.
void	performAdd(Triple t) Add a triple to the triple store.
void	performDelete(Triple t) Remove a triple from the triple store.
void	remove(Node s, Node p, Node o) Remove all triples that match by find(s, p, o)
int	size() Answer the size of this graph (ie the number of exposed triples).
String	toString() Answer a human-consumable representation of this graph.
static String	toString(String prefix, Graph that) Answer a human-consumable representation of that.

Methods inherited from class java.lang.Object

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

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

find

Field Detail

TOSTRING_TRIPLE_BASE

public static final int TOSTRING_TRIPLE_BASE

toString will not cut off up to this number of triples.

See Also:

Constant Field Values

TOSTRING_TRIPLE_LIMIT

public static final int TOSTRING_TRIPLE_LIMIT

toString will not output more than this number of triples.

See Also:

Constant Field Values

Constructor Detail

GraphBase

public GraphBase()

Initialise this graph as one with reification style Minimal.

Method Detail

close

public void close()

Close this graph. Subgraphs may extend to discard resources.

Specified by:

close in interface Graph

isClosed

public boolean isClosed()

Description copied from interface: Graph

Answer true iff .close() has been called on this Graph.

Specified by:

isClosed in interface Graph

dependsOn

public boolean dependsOn(Graph other)

Default implementation answers true iff this graph is the same graph as the argument graph.

Specified by:

dependsOn in interface Graph

Parameters:

other - the graph this graph may depend on

Returns:

false if this does not depend on other

getStatisticsHandler

@Deprecated
public GraphStatisticsHandler getStatisticsHandler()

Deprecated.

Description copied from interface: Graph

Answer this Graph's statistics handler, or null if there isn't one. Every call to this method on a particular graph delivers the same (==) answer.

Specified by:

getStatisticsHandler in interface Graph

getEventManager

public GraphEventManager getEventManager()

Answer the event manager for this graph; allocate a new one if required. Subclasses may override if they have a more specialised event handler. The default is a SimpleEventManager.

Specified by:

getEventManager in interface Graph

notifyAdd

public void notifyAdd(Triple t)

Tell the event manager that the triple t has been added to the graph.

notifyDelete

public void notifyDelete(Triple t)

Tell the event manager that the triple t has been deleted from the graph.

getTransactionHandler

public TransactionHandler getTransactionHandler()

Answer a transaction handler bound to this graph. The default is SimpleTransactionHandler, which handles no transactions.

Specified by:

getTransactionHandler in interface Graph

getCapabilities

public Capabilities getCapabilities()

Answer the capabilities of this graph; the default is an AllCapabilities object (the same one each time, not that it matters - Capabilities should be immutable).

Specified by:

getCapabilities in interface Graph

getPrefixMapping

public PrefixMapping getPrefixMapping()

Answer the PrefixMapping object for this graph, the same one each time.

Specified by:

getPrefixMapping in interface Graph

add

public void add(Triple t)

Add a triple, and notify the event manager. Subclasses should not need to override this - we might make it final. The triple is added using performAdd, and notification done by notifyAdd.

Specified by:

add in interface Graph

Parameters:

t - the triple to add to the graph

performAdd

public void performAdd(Triple t)

Add a triple to the triple store. The default implementation throws an AddDeniedException; subclasses must override if they want to be able to add triples.

Specified by:

performAdd in interface GraphWithPerform

delete

public final void delete(Triple t)

Delete a triple, and notify the event manager. Subclasses should not need to override this - we might make it final. The triple is added using performDelete, and notification done by notifyDelete.

Specified by:

delete in interface Graph

Parameters:

t - the triple to delete to the graph

performDelete

public void performDelete(Triple t)

Remove a triple from the triple store. The default implementation throws a DeleteDeniedException; subclasses must override if they want to be able to remove triples.

Specified by:

performDelete in interface GraphWithPerform

clear

public void clear()

Remove all the statements from this graph.

Specified by:

clear in interface Graph

remove

public void remove(Node s,
                   Node p,
                   Node o)

Remove all triples that match by find(s, p, o)

Specified by:

remove in interface Graph

find

public final ExtendedIterator<Triple> find(Triple m)

Description copied from interface: Graph

Returns an iterator over all the Triples that match the triple pattern.

Specified by:

find in interface Graph

Parameters:

m - a Triple encoding the pattern to look for

Returns:

an iterator of all triples in this graph that match m

forTestingOnly_graphBaseFind

public ExtendedIterator<Triple> forTestingOnly_graphBaseFind(Triple t)

find

public final ExtendedIterator<Triple> find(Node s,
                                           Node p,
                                           Node o)

Description copied from interface: Graph

Returns an iterator over Triples matching a pattern.

Specified by:

find in interface Graph

Returns:

an iterator of all triples in this graph

contains

public final boolean contains(Triple t)

Answer true iff t is in the graph as revealed by find(t) being non-empty. t may contain ANY wildcards. Sub-classes may over-ride graphBaseContains for efficiency.

Specified by:

contains in interface Graph

contains

public final boolean contains(Node s,
                              Node p,
                              Node o)

Answer true if this graph contains (s, p, o); this canonical implementation cannot be over-ridden.

Specified by:

contains in interface Graph

size

public final int size()

Answer the size of this graph (ie the number of exposed triples). Defined as the size of the triple store plus the size of the reification store. Subclasses must override graphBaseSize() to reimplement (and reifierSize if they have some special reason for redefined that).

Specified by:

size in interface Graph

isEmpty

public boolean isEmpty()

Answer true iff this graph contains no triples (hidden reification quads do not count). The default implementation is size() == 0, which is fine if size is reasonable efficient. Subclasses may override if necessary. This method may become final and defined in terms of other methods.

Specified by:

isEmpty in interface Graph

isIsomorphicWith

public boolean isIsomorphicWith(Graph g)

Answer true iff this graph is isomorphic to g according to the algorithm (indeed, method) in GraphMatcher.

Specified by:

isIsomorphicWith in interface Graph

Parameters:

g - Compare against this.

Returns:

boolean True if the two graphs are isomorphic.

toString

public String toString()

Answer a human-consumable representation of this graph. Not advised for big graphs, as it generates a big string: intended for debugging purposes.

Overrides:

toString in class Object

toString

public static String toString(String prefix,
                              Graph that)

Answer a human-consumable representation of that. The string prefix will appear near the beginning of the string. Nodes may be prefix-compressed using that's prefix-mapping. This default implementation will display all the triples exposed by the graph (ie including reification triples if it is Standard).