TcManager (Clerezza - SCB Core 0.12-incubating API)

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org.apache.clerezza.rdf.core.access
Class TcManager

java.lang.Object
  org.apache.clerezza.rdf.core.access.TcProviderMultiplexer
      org.apache.clerezza.rdf.core.access.TcManager

All Implemented Interfaces:: TcProvider

@Service(value=TcManager.class) @Reference(name="weightedTcProvider", policy=DYNAMIC, referenceInterface=WeightedTcProvider.class, cardinality=MANDATORY_MULTIPLE) public class TcManager
extends TcProviderMultiplexer
extends TcProviderMultiplexer

This class implements TcManager, delegating the actual provision and creation of Graphs or MGraphs to registered TcProviders. The class attempts to satisfy the request using the register WeightedTcProvider in decreasing order of weight. If multiple providers have the same weight the lexicographical order of the fully qualified class name determines which one is used, namely the one that occurs earlier. If a call to a registered provider causes an IllegalArgumentException, NoSuchEntityException or UnsupportedOperationException then the call is delegated to the next provider. Only one instance of this class should exist in a system, the public no argument constructor is meant for initialization by dependency injection systems such as OSGi-DS. Applications should use the static getInstance() method if they aren't using a framework that injects them the instance. This class returns LockableMGraphs a subtype of MGraph that allows read/write locks.

Author:: reto, mir, hasan

Field Summary
`protected QueryEngine`	`queryEngine`

Constructor Summary
`TcManager()` the constructor sets the singleton instance to allow instantiation by OSGi-DS.

Method Summary
`protected void`	`activate(org.osgi.service.component.ComponentContext componentContext)`
`protected void`	`bindWeightedTcProvider(WeightedTcProvider provider)` Registers a provider
`Graph`	`createGraph(UriRef name, TripleCollection triples)` Creates a `Graph` with a specified name
`LockableMGraph`	`createMGraph(UriRef name)` Creates an initially empty `MGraph` with a specified name
`protected void`	`deactivate(org.osgi.service.component.ComponentContext componentContext)`
`void`	`deleteTripleCollection(UriRef name)` Deletes the `Graph` or `MGraph` of a specified name.
`boolean`	`executeSparqlQuery(AskQuery query, TripleCollection defaultGraph)` Executes a sparql ASK query.
`Graph`	`executeSparqlQuery(ConstructQuery query, TripleCollection defaultGraph)` Executes a sparql CONSTRUCT query.
`Graph`	`executeSparqlQuery(DescribeQuery query, TripleCollection defaultGraph)` Executes a sparql DESCRIBE query.
`Object`	`executeSparqlQuery(Query query, TripleCollection defaultGraph)` Executes any sparql query.
`ResultSet`	`executeSparqlQuery(SelectQuery query, TripleCollection defaultGraph)` Executes a sparql SELECT query.
`Graph`	`getGraph(UriRef name)` Get a `Graph` by its name
`static TcManager`	`getInstance()` This returns the singleton instance.
`LockableMGraph`	`getMGraph(UriRef name)` Get an `MGraph` by its name.
`Set<UriRef>`	`getNames(Graph graph)` get a set of the names of a `Graph`
`TcAccessController`	`getTcAccessController()`
`TripleCollection`	`getTriples(UriRef name)` This method is used to get a `TripleCollection` indifferently whether it's a Graph or an MGraph.
`protected void`	`graphAppears(UriRef name)` subclasses overwrite this method to be notified when a new Graph is available (either because it has been created or being provided by a newly added WeightedTcProvider).
`Set<UriRef>`	`listGraphs()` Lists the name of the `Graph`s available through this `TcProvider`, implementations may take into account the security context and omit `Graph`s for which access is not allowed.
`Set<UriRef>`	`listMGraphs()` Lists the name of the `MGraph`s available through this `TcProvider`, implementations may take into account the security context and omit `MGraph`s for which access is not allowed.
`Set<UriRef>`	`listTripleCollections()` Lists the name of the `TripleCollection`s available through this `TcProvider` indifferently whether they are Graphs or an MGraphs, implementations may take into account the security context and omit `TripleCollection`s for which access is not allowed.
`protected void`	`mGraphAppears(UriRef name)` subclasses overwrite this method to be notified when a new MGraph is available (either because it has been created or being provided by a newly added WeightedTcProvider).
`protected void`	`tcDisappears(UriRef name)` subclasses overwrite this method to be notified whenTripleCollection is no longer available (either because it has been deleted or bacause its WeightedTcProvider was removed).
`protected void`	`unbindWeightedTcProvider(WeightedTcProvider provider)` Unregister a provider

Methods inherited from class org.apache.clerezza.rdf.core.access.TcProviderMultiplexer
`addWeightedTcProvider, getProviderList, removeWeightedTcProvider`

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Field Detail

queryEngine

@Reference(policy=DYNAMIC,
           cardinality=MANDATORY_UNARY)
protected QueryEngine queryEngine

Constructor Detail

TcManager

public TcManager()

the constructor sets the singleton instance to allow instantiation by OSGi-DS. This constructor should not be called except by OSGi-DS, otherwise the static getInstance method should be used.

Method Detail

getInstance

public static TcManager getInstance()

This returns the singleton instance. If an instance has been previously created (e.g. by OSGi declarative services) this instance is returned, otherwise a new instance is created and providers are injected using the service provider interface (META-INF/services/)

Returns:: the singleton instance

activate

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