Remove duplicate creation of RDFox datastores

3 files changed, 20 insertions, 32 deletions

diff --git a/src/main/scala/uk/ac/ox/cs/rsacomb/RSAOntology.scala b/src/main/scala/uk/ac/ox/cs/rsacomb/RSAOntology.scala
index 4693e04..24045de 100644
--- a/src/main/scala/uk/ac/ox/cs/rsacomb/RSAOntology.scala
+++ b/src/main/scala/uk/ac/ox/cs/rsacomb/RSAOntology.scala
@@ -59,6 +59,9 @@ object RSAOntology {
   // Counter used to implement a simple fresh variable generator
   private var counter = -1;
 
+  /** Name of the RDFox data store used for CQ answering */
+  private val DataStore = "answer_computation"
+
   def apply(ontology: OWLOntology): RSAOntology = new RSAOntology(ontology)
 
   def apply(ontology: File): RSAOntology =
@@ -119,7 +122,10 @@ class RSAOntology(val ontology: OWLOntology) extends RSAAxiom {
       .flatMap(_.objectPropertyExpressionsInSignature)
       .distinct
 
-  // OWLAPI reasoner for same easier tasks
+  /** OWLAPI reasoner
+    *
+    * Used to carry out some preliminary reasoning task.
+    */
   private val reasoner =
     (new StructuralReasonerFactory()).createReasoner(ontology)
 
@@ -300,7 +306,7 @@ class RSAOntology(val ontology: OWLOntology) extends RSAAxiom {
     */
   def ask(query: ConjunctiveQuery): ConjunctiveQueryAnswers = {
     import implicits.JavaCollections._
-    val (server, data) = RDFoxHelpers.openConnection("AnswerComputation")
+    val (server, data) = RDFoxHelpers.openConnection(RSAOntology.DataStore)
     data.addRules(this.canonicalModel.rules)
     data.addRules(this.filteringProgram(query).rules)
     val answers = RDFoxHelpers
@@ -317,9 +323,12 @@ class RSAOntology(val ontology: OWLOntology) extends RSAAxiom {
     answers
   }
 
-  /** Query the logic program used to compute answers to a given CQ.
+  /** Query the RDFox data store used for query answering.
     *
-    * This method has been introduced mostly for debugging purposes.
+    * @note This method does not add any facts or rules to the data
+    * store. It is most useful after the execution of a query using
+    * [[uk.ac.ox.cs.rsacomb.RSAOntology.ask RSAOntology.ask]].
+    * @note This method has been introduced mostly for debugging purposes.
     *
     * @param cq a CQ used to compute the environment.
     * @param query query to be executed against the environment
@@ -327,20 +336,14 @@ class RSAOntology(val ontology: OWLOntology) extends RSAAxiom {
     * an empty set.
     * @param opts additional options to RDFox.
     * @return a collection of answers to the input query.
-    *
-    * @todo this function currently fails because RDFox reports a
-    * datastore duplication.
     */
-  def queryEnvironment(
+  def queryDataStore(
       cq: ConjunctiveQuery,
       query: String,
       prefixes: Prefixes = new Prefixes(),
       opts: ju.Map[String, String] = new ju.HashMap[String, String]()
   ): Option[Seq[Seq[Resource]]] = {
-    import implicits.JavaCollections._
-    val (server, data) = RDFoxHelpers.openConnection("AnswerComputation")
-    data.addRules(this.canonicalModel.rules)
-    data.addRules(this.filteringProgram(cq).rules)
+    val (server, data) = RDFoxHelpers.openConnection(RSAOntology.DataStore)
     val answers = RDFoxHelpers.submitQuery(data, query, prefixes, opts)
     RDFoxHelpers.closeConnection(server, data)
     answers
diff --git a/src/main/scala/uk/ac/ox/cs/rsacomb/sparql/ConjunctiveQuery.scala b/src/main/scala/uk/ac/ox/cs/rsacomb/sparql/ConjunctiveQuery.scala
index 4d397d8..e77a913 100644
--- a/src/main/scala/uk/ac/ox/cs/rsacomb/sparql/ConjunctiveQuery.scala
+++ b/src/main/scala/uk/ac/ox/cs/rsacomb/sparql/ConjunctiveQuery.scala
@@ -104,21 +104,5 @@ class ConjunctiveQuery(
   /** Returns the collection of bounded (existential) variables in the query. */
   val bounded: Set[Variable] = variables &~ answer
 
-  /** Returns the answers to a query
-    *
-    * @param data data store against which the query is executed
-    * @param opts additional options passed to RDFox
-    * @return a new [[ConjunctiveQueryAnswers]] instance containing the
-    *         collection of answers.
-    */
-  def answers(
-      data: DataStoreConnection,
-      opts: JMap[String, String] = new JHashMap[String, String]()
-  ): ConjunctiveQueryAnswers =
-    new ConjunctiveQueryAnswers(
-      bcq,
-      RDFoxHelpers.submitSelectQuery(data, query, opts)
-    )
-
   override def toString(): String = query.toString
 }
diff --git a/src/main/scala/uk/ac/ox/cs/rsacomb/util/RDFoxHelpers.scala b/src/main/scala/uk/ac/ox/cs/rsacomb/util/RDFoxHelpers.scala
index 369da7f..0f3a1cf 100644
--- a/src/main/scala/uk/ac/ox/cs/rsacomb/util/RDFoxHelpers.scala
+++ b/src/main/scala/uk/ac/ox/cs/rsacomb/util/RDFoxHelpers.scala
@@ -37,7 +37,7 @@ object RDFoxHelpers {
     * details on how to close an open connection.
     */
   def openConnection(
-      dataStore: String,
+      datastore: String,
       opts: RDFoxOpts = RDFoxOpts()
   ): (ServerConnection, DataStoreConnection) = {
     val serverUrl = "rdfox:local"
@@ -45,8 +45,9 @@ object RDFoxHelpers {
     val password = ""
     val server =
       ConnectionFactory.newServerConnection(serverUrl, role, password)
-    server.createDataStore(dataStore, "par-complex-nn", opts)
-    val data = server.newDataStoreConnection(dataStore)
+    if (!server.containsDataStore(datastore))
+      server.createDataStore(datastore, "par-complex-nn", opts)
+    val data = server.newDataStoreConnection(datastore)
     (server, data)
   }
 
@@ -153,8 +154,8 @@ object RDFoxHelpers {
       server: ServerConnection,
       data: DataStoreConnection
   ): Unit = {
-    server.close();
     data.close();
+    server.close();
   }
 
 }