Package org.eclipse.rdf4j.sail.lucene

Class LuceneSailConnection

  • All Implemented Interfaces:
    AutoCloseable, FederatedServiceResolverClient, ThreadSafetyAware, NotifyingSailConnection, SailConnection
    public class LuceneSailConnection
extends NotifyingSailConnectionWrapper

    Sail Connection Listener instead of implementing add/remove

    Using SailConnectionListener, see above The LuceneIndex is adapted based on events coming from the wrapped Sail, rather than by overriding the addStatement and removeStatements methods. This approach has two benefits: (1) when the wrapped Sail only reports statements that were not stored before, the LuceneIndex does not have to do the check on the skipped statemements and (2) the method for removing Statements from the Lucene index does not have to take wildcards into account, making its implementation simpler.

    Synchronized Methods

    LuceneSailConnection uses a listener to collect removed statements. The listener should not be active during the removal of contexts, as this is not needed (context removal is implemented differently). To realize this, all methods that can do changes are synchronized and during context removal, the listener is disabled. Thus, all methods of this connection that can change data are synchronized.

    Evaluating Queries - possible optimizations

    Arjohn has answered this question in the sesame-dev mailinglist on 13.8.2007: Is there a QueryModelNode that can contain a fixed (perhaps very long) list of Query result bindings? There is currently no such node, but there are two options to get similar behaviour: 1) Include the result bindings as OR-ed constraints in the query model. E.g. if you have a result binding like {{x=1,y=1},{x=2,y=2}}, this translates to the constraints (x=1 and y=1) or (x=2 and y=2). 2) The LuceneSail could iterate over the LuceneQueryResult and supply the various results as query input parameters to the underlying Sail. This is similar to using PreparedStatement's in JDBC.
    Author:
    sauermann, christian.huetter

    • Field Detail

      • connectionListener

        protected final SailConnectionListener connectionListener
        The listener that listens to the underlying connection. It is disabled during clearContext operations.

    • Method Detail

      • addStatement

        public void addStatement​(Resource subj,
                         IRI pred,
                         Value obj,
                         Resource... contexts)
                  throws SailException
        Description copied from interface: SailConnection
        Adds a statement to the store.
        Specified by:
        addStatement in interface SailConnection
        Overrides:
        addStatement in class SailConnectionWrapper
        Parameters:
        subj - The subject of the statement to add.
        pred - The predicate of the statement to add.
        obj - The object of the statement to add.
        contexts - The context(s) to add the statement to. Note that this parameter is a vararg and as such is optional. If no contexts are specified, a context-less statement will be added.
        Throws:
        SailException - If the statement could not be added, for example because no transaction is active.

      • clear

        public void clear​(Resource... contexts)
           throws SailException
        Description copied from interface: SailConnection
        Removes all statements from the specified/all contexts. If no contexts are specified the method operates on the entire repository.
        Specified by:
        clear in interface SailConnection
        Overrides:
        clear in class SailConnectionWrapper
        Parameters:
        contexts - The context(s) from which to remove the statements. Note that this parameter is a vararg and as such is optional. If no contexts are specified the method operates on the entire repository. A null value can be used to match context-less statements.
        Throws:
        SailException - If the statements could not be removed.

      • evaluate

        public CloseableIteration<? extends BindingSet,​QueryEvaluationException> evaluate​(TupleExpr tupleExpr,
                                                                                        Dataset dataset,
                                                                                        BindingSet bindings,
                                                                                        boolean includeInferred)
                                                                                 throws SailException
        Description copied from interface: SailConnection
        Evaluates the supplied TupleExpr on the data contained in this Sail object, using the (optional) dataset and supplied bindings as input parameters.
        Specified by:
        evaluate in interface SailConnection
        Overrides:
        evaluate in class SailConnectionWrapper
        Parameters:
        tupleExpr - The tuple expression to evaluate.
        dataset - The dataset to use for evaluating the query, null to use the Sail's default dataset.
        bindings - A set of input parameters for the query evaluation. The keys reference variable names that should be bound to the value they map to.
        includeInferred - Indicates whether inferred triples are to be considered in the query result. If false, no inferred statements are returned; if true, inferred statements are returned if available
        Returns:
        The TupleQueryResult.
        Throws:
        SailException - If the Sail object encountered an error or unexpected situation internally.

      • removeStatements

        public void removeStatements​(Resource subj,
                             IRI pred,
                             Value obj,
                             Resource... contexts)
                      throws SailException
        Description copied from interface: SailConnection
        Removes all statements matching the specified subject, predicate and object from the repository. All three parameters may be null to indicate wildcards.
        Specified by:
        removeStatements in interface SailConnection
        Overrides:
        removeStatements in class SailConnectionWrapper
        Parameters:
        subj - The subject of the statement that should be removed, or null to indicate a wildcard.
        pred - The predicate of the statement that should be removed, or null to indicate a wildcard.
        obj - The object of the statement that should be removed , or null to indicate a wildcard. *
        contexts - The context(s) from which to remove the statement. Note that this parameter is a vararg and as such is optional. If no contexts are specified the method operates on the entire repository. A null value can be used to match context-less statements.
        Throws:
        SailException - If the statement could not be removed, for example because no transaction is active.

      • rollback

        public void rollback()
              throws SailException
        Description copied from interface: SailConnection
        Rolls back the transaction, discarding any uncommitted changes that have been made in this SailConnection.
        Specified by:
        rollback in interface SailConnection
        Overrides:
        rollback in class SailConnectionWrapper
        Throws:
        UnknownSailTransactionStateException - If the transaction state can not be determined (this can happen for instance when communication between client and server fails or times-out). It does not indicate a problem with the integrity of the store.
        SailException - If the SailConnection could not be rolled back.