org.apache.clerezza.rdf.file.storage

Class FileTcProvider

java.lang.Object

org.apache.clerezza.rdf.file.storage.FileTcProvider

All Implemented Interfaces:

TcProvider, WeightedTcProvider

public class FileTcProvider
extends Object
implements WeightedTcProvider

The FileTcProvider is a WeightedTcProvider that stores MGraphS in the file system. GraphS are not supported. The UriRef of a MGraph is location of the file in the file system (e.g. "file:///home/user/myGraph.rdf"). The format of the rdf data in the file depends on the file ending, for example ".rdf" or ".ttl". FileTcProvider uses org.apache.clerezza.rdf.core.serializedform.Parser and org.apache.clerezza.rdf.core.serializedform.Serializer for parsing and serialization, therefore the supported formats depend on the availability of these services. The default weight of the provider is 300.

Author:

mir

Field Summary

Fields

Modifier and Type	Field and Description
protected static File	dataFile

Constructor Summary

Constructors

Constructor and Description
FileTcProvider()

Method Summary

Methods

Modifier and Type	Method and Description
protected void	activate(org.osgi.service.component.ComponentContext componentContext)
Graph	createGraph(UriRef name, TripleCollection triples) Creates a Graph with a specified name
MGraph	createMGraph(UriRef name) Creates an initially empty MGraph with a specified name
void	deleteTripleCollection(UriRef name) Deletes the Graph or MGraph of a specified name.
Graph	getGraph(UriRef name) Get a Graph by its name
MGraph	getMGraph(UriRef name) Get an MGraph by its name.
Set<UriRef>	getNames(Graph graph) get a set of the names of a Graph
TripleCollection	getTriples(UriRef name) This method is used to get a TripleCollection indifferently whether it's a Graph or an MGraph.
int	getWeight() Get the weight of this provider.
Set<UriRef>	listGraphs() Lists the name of the Graphs available through this TcProvider, implementations may take into account the security context and omit Graphs for which access is not allowed.
Set<UriRef>	listMGraphs() Lists the name of the MGraphs available through this TcProvider, implementations may take into account the security context and omit MGraphs for which access is not allowed.
Set<UriRef>	listTripleCollections() Lists the name of the TripleCollections available through this TcProvider indifferently whether they are Graphs or an MGraphs, implementations may take into account the security context and omit TripleCollections for which access is not allowed.

Methods inherited from class java.lang.Object

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

Field Detail

dataFile

protected static File dataFile

Constructor Detail

FileTcProvider

public FileTcProvider()

Method Detail

activate

protected void activate(org.osgi.service.component.ComponentContext componentContext)

getWeight

public int getWeight()

Description copied from interface: WeightedTcProvider

Get the weight of this provider. TcManager will prioritize TcProviders with greater weight.

Specified by:

getWeight in interface WeightedTcProvider

Returns:

a positive number indicating the weight of the provider

getGraph

public Graph getGraph(UriRef name)
               throws NoSuchEntityException

Description copied from interface: TcProvider

Get a Graph by its name

Specified by:

getGraph in interface TcProvider

Parameters:

name - the name of the Graph

Returns:

the Graph with the specified name

Throws:

NoSuchEntityException - if there is no Graph with the specified name

getMGraph

public MGraph getMGraph(UriRef name)
                 throws NoSuchEntityException

Get an MGraph by its name. If the file at the specified location already exists, then a MGraph is returned even though it was not created with createMGraph().

Specified by:

getMGraph in interface TcProvider

Parameters:

the - name of the MGraph

Returns:

name the MGraph with the specified name

Throws:

NoSuchEntityException - if there is no MGraph with the specified name or the file didn't exist.

getTriples

public TripleCollection getTriples(UriRef name)
                            throws NoSuchEntityException

Description copied from interface: TcProvider

This method is used to get a TripleCollection indifferently whether it's a Graph or an MGraph. If the name names an MGraph the result is the same as when invoking getMGraph with that argument, analogously for GraphS the method returns an instance equals to what getGraph would return.

Specified by:

getTriples in interface TcProvider

Parameters:

name - the name of the Graph or MGraph

Returns:

the Graph or MGraph

Throws:

NoSuchEntityException - if there is no Graph or MGraph with the specified name

listGraphs

public Set<UriRef> listGraphs()

Description copied from interface: TcProvider

Lists the name of the Graphs available through this TcProvider, implementations may take into account the security context and omit Graphs for which access is not allowed.

Specified by:

listGraphs in interface TcProvider

Returns:

the list of Graphs

listMGraphs

public Set<UriRef> listMGraphs()

Description copied from interface: TcProvider

Lists the name of the MGraphs available through this TcProvider, implementations may take into account the security context and omit MGraphs for which access is not allowed.

Specified by:

listMGraphs in interface TcProvider

Returns:

the list of MGraphs

listTripleCollections

public Set<UriRef> listTripleCollections()

Description copied from interface: TcProvider

Lists the name of the TripleCollections available through this TcProvider indifferently whether they are Graphs or an MGraphs, implementations may take into account the security context and omit TripleCollections for which access is not allowed.

Specified by:

listTripleCollections in interface TcProvider

Returns:

the list of TripleCollections

createMGraph

public MGraph createMGraph(UriRef name)
                    throws UnsupportedOperationException,
                           EntityAlreadyExistsException

Description copied from interface: TcProvider

Creates an initially empty MGraph with a specified name

Specified by:

createMGraph in interface TcProvider

Parameters:

name - names the new MGraph

Returns:

the newly created MGraph

Throws:

UnsupportedOperationException - if this provider doesn't support creating MGraphS

EntityAlreadyExistsException - if an MGraph with the specified name already exists

createGraph

public Graph createGraph(UriRef name,
                TripleCollection triples)
                  throws UnsupportedOperationException,
                         EntityAlreadyExistsException

Description copied from interface: TcProvider

Creates a Graph with a specified name

Specified by:

createGraph in interface TcProvider

Parameters:

name - the name of the Graph to be created

triples - the triples of the new Graph

Returns:

the newly created Graph

Throws:

UnsupportedOperationException - if this provider doesn't support creating GraphS

EntityAlreadyExistsException - if a Graph with the specified name already exists

deleteTripleCollection

public void deleteTripleCollection(UriRef name)
                            throws UnsupportedOperationException,
                                   NoSuchEntityException,
                                   EntityUndeletableException

Description copied from interface: TcProvider

Deletes the Graph or MGraph of a specified name. If name references a Graph and the graph has other names, it will still be available with those other names.

Specified by:

deleteTripleCollection in interface TcProvider

Parameters:

name - the entity to be removed

Throws:

UnsupportedOperationException - if this provider doesn't support entities deletion.

NoSuchEntityException - if name doesn't refer to a Graph or an MGraph.

EntityUndeletableException - if the specified Graph is undeletable

getNames

public Set<UriRef> getNames(Graph graph)

Description copied from interface: TcProvider

get a set of the names of a Graph

Specified by:

getNames in interface TcProvider

Returns:

the set names of Graph, the set is empty if Graph is unknown