Merge pull request #62 from swiss-art-research-net/feature/qlever

Add Qlever repo connector

src/main/java/org/researchspace/repository/sparql/CustomSPARQLConnection.java

@@ -33,8 +33,8 @@ public CustomSPARQLConnection(SPARQLRepository repository, SPARQLProtocolSession
         this.enableSilentMode(isSilentMode);
     }
 
-    public CustomSPARQLConnection(SPARQLRepository repository, SPARQLProtocolSession client) {
-        super(repository, client);
+    public CustomSPARQLConnection(SPARQLRepository repository, SPARQLProtocolSession client, boolean quadMode) {
+        super(repository, client, quadMode);
     }
 
     @Override

src/main/java/org/researchspace/repository/sparql/qlever/QLeverRepository.java

@@ -0,0 +1,41 @@
+/**
+ * ResearchSpace
+ * Copyright (C) 2024, PHAROS: The International Consortium of Photo Archives
+ *
+ * This program is free software: you can redistribute it and/or modify it under
+ * the terms of the GNU Affero General Public License as published by the Free
+ * Software Foundation, either version 3 of the License, or (at your option) any
+ * later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.researchspace.repository.sparql.qlever;
+
+import org.eclipse.rdf4j.repository.RepositoryConnection;
+import org.eclipse.rdf4j.repository.RepositoryException;
+import org.researchspace.repository.sparql.CustomSPARQLRepository;
+
+/**
+ * Repository imlementation for QLever SPARQL endpoint.
+ *
+ * @see https://github.com/ad-freiburg/qlever
+ * @see QLeverRepositoryConnection
+ * @author Artem Kozlov
+ */
+public class QLeverRepository extends CustomSPARQLRepository {
+    public QLeverRepository(String endpointUrl) {
+        super(endpointUrl);
+    }
+
+    @Override
+    public RepositoryConnection getConnection() throws RepositoryException {
+        // qlever doesn't support quads, for now
+        return new QLeverRepositoryConnection(this, createHTTPClient(), false);
+    }
+}

src/main/java/org/researchspace/repository/sparql/qlever/QLeverRepositoryConfig.java

@@ -0,0 +1,33 @@
+/**
+ * ResearchSpace
+ * Copyright (C) 2024, PHAROS: The International Consortium of Photo Archives
+ *
+ * This program is free software: you can redistribute it and/or modify it under
+ * the terms of the GNU Affero General Public License as published by the Free
+ * Software Foundation, either version 3 of the License, or (at your option) any
+ * later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.researchspace.repository.sparql.qlever;
+
+import org.researchspace.repository.sparql.MpSPARQLRepositoryConfig;
+
+/**
+ * Implementation config for {@link QLeverRepository}.
+ * 
+ * @author Artem Kozlov
+ */
+public class QLeverRepositoryConfig extends MpSPARQLRepositoryConfig {
+
+    public QLeverRepositoryConfig() {
+        super();
+        setType(QLeverRepositoryFactory.REPOSITORY_TYPE);
+    }
+}

src/main/java/org/researchspace/repository/sparql/qlever/QLeverRepositoryConnection.java

@@ -0,0 +1,51 @@
+/**
+ * ResearchSpace
+ * Copyright (C) 2024, PHAROS: The International Consortium of Photo Archives
+ *
+ * This program is free software: you can redistribute it and/or modify it under
+ * the terms of the GNU Affero General Public License as published by the Free
+ * Software Foundation, either version 3 of the License, or (at your option) any
+ * later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.researchspace.repository.sparql.qlever;
+
+import org.eclipse.rdf4j.http.client.SPARQLProtocolSession;
+import org.eclipse.rdf4j.query.BooleanQuery;
+import org.eclipse.rdf4j.query.MalformedQueryException;
+import org.eclipse.rdf4j.query.QueryLanguage;
+import org.eclipse.rdf4j.query.TupleQuery;
+import org.eclipse.rdf4j.repository.RepositoryException;
+import org.eclipse.rdf4j.repository.sparql.SPARQLRepository;
+import org.researchspace.api.sparql.SparqlUtil;
+import org.researchspace.repository.sparql.CustomSPARQLConnection;
+import org.researchspace.repository.sparql.virtuoso.VirtuosoWrapperBooleanQuery;
+
+/**
+ * A wrapper connection for a QLever SPARQL repository.
+ * 
+ * Supports ASK queries, by transforming them into equivalent SELECT * {} LIMIT 1
+ * 
+ * @author Artem Kozlov
+ */
+public class QLeverRepositoryConnection extends CustomSPARQLConnection {
+    public QLeverRepositoryConnection(SPARQLRepository repository, SPARQLProtocolSession client, boolean quadMode) {
+        super(repository, client, quadMode);
+    }
+
+    @Override
+    public BooleanQuery prepareBooleanQuery(QueryLanguage ql, String query, String base)
+            throws RepositoryException, MalformedQueryException {
+        String selectQueryString = SparqlUtil.transformAskToSelect(query);
+        TupleQuery tupleQuery = prepareTupleQuery(selectQueryString);
+        VirtuosoWrapperBooleanQuery wrapperQuery = new VirtuosoWrapperBooleanQuery(query, tupleQuery);
+        return wrapperQuery;
+    }
+}

src/main/java/org/researchspace/repository/sparql/qlever/QLeverRepositoryFactory.java

@@ -0,0 +1,57 @@
+/**
+ * ResearchSpace
+ * Copyright (C) 2024, PHAROS: The International Consortium of Photo Archives
+ *
+ * This program is free software: you can redistribute it and/or modify it under
+ * the terms of the GNU Affero General Public License as published by the Free
+ * Software Foundation, either version 3 of the License, or (at your option) any
+ * later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.researchspace.repository.sparql.qlever;
+
+import org.eclipse.rdf4j.repository.config.RepositoryConfigException;
+import org.eclipse.rdf4j.repository.config.RepositoryFactory;
+import org.eclipse.rdf4j.repository.config.RepositoryImplConfig;
+import org.eclipse.rdf4j.repository.sparql.config.SPARQLRepositoryConfig;
+import org.researchspace.repository.sparql.AbstractMpSPARQLRepositoryFactory;
+import org.researchspace.repository.sparql.MpSPARQLRepositoryConfig;
+
+/**
+ * A {@link RepositoryFactory} implementation for a QLever repository.
+ * 
+ * @author Artem Kozlov
+ */
+public class QLeverRepositoryFactory extends AbstractMpSPARQLRepositoryFactory {
+
+    public static final String REPOSITORY_TYPE = "researchspace:QLeverRepository";
+
+    @Override
+    public String getRepositoryType() {
+        return REPOSITORY_TYPE;
+    }
+
+    @Override
+    public RepositoryImplConfig getConfig() {
+        return new QLeverRepositoryConfig();
+    }
+
+    @Override
+    public QLeverRepository getRepositoryInternal(MpSPARQLRepositoryConfig config) throws RepositoryConfigException {
+        if (config instanceof SPARQLRepositoryConfig) {
+            SPARQLRepositoryConfig httpConfig = config;
+            QLeverRepository result = new QLeverRepository(httpConfig.getQueryEndpointUrl());
+            result.setWritable(config.isWritable());
+            return result;
+        } else {
+            throw new RepositoryConfigException("Invalid configuration class: " + config.getClass());
+        }
+    }
+}

src/main/resources/META-INF/services/org.eclipse.rdf4j.repository.config.RepositoryFactory

@@ -5,3 +5,4 @@ org.researchspace.federation.repository.MpFederationSailRepositoryFactory
 org.researchspace.repository.memory.MpMemoryRepositoryFactory
 org.researchspace.repository.sparql.virtuoso.VirtuosoWrapperRepositoryFactory
 org.researchspace.repository.sparql.bearertoken.SPARQLBearerTokenAuthRepositoryFactory
+org.researchspace.repository.sparql.qlever.QLeverRepositoryFactory

src/main/resources/org/researchspace/apps/default/config/repository-templates/qlever.ttl

@@ -0,0 +1,17 @@
+# platform configuration template for a QLever SPARQL repository
+#
+@prefix rep: <http://www.openrdf.org/config/repository#> .
+@prefix sail: <http://www.openrdf.org/config/sail#> .
+@prefix sr: <http://www.openrdf.org/config/repository/sail#> .
+@prefix sparqlr: <http://www.openrdf.org/config/repository/sparql#> .
+@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
+@prefix mph: <http://www.researchspace.org/resource/system/repository#> .
+
+
+[] a rep:Repository ;
+   rep:repositoryID "my-qlever-repo" ; # Replace with your repository ID or leave default if this is the main repository
+   rdfs:label "QLever SPARQL repository" ; # Replace with a meaningful description for this repository
+   rep:repositoryImpl [
+      rep:repositoryType "researchspace:QLeverRepository" ;
+      sparqlr:query-endpoint <http://example.org/query> # Replace with the URL of the SPARQL endpoint to submit queries to
+   ].