ulo-storage-endpoint: add some counting functionality

src/ulo-storage-endpoint/src/main/java/info/mathhub/uloapi/cli/Main.java

+package info.mathhub.uloapi.cli;
+
+import info.mathhub.uloapi.query.GraphDB;
+import info.mathhub.uloapi.query.ULO;
+import org.eclipse.rdf4j.model.IRI;
+import org.eclipse.rdf4j.model.Statement;
+import org.eclipse.rdf4j.repository.RepositoryResult;
+
+import java.util.Arrays;
+import java.util.Iterator;
+import java.util.List;
+
+public class Main {
+    public static void main(String[] args) {
+        final List<IRI> predicates = Arrays.asList(
+                ULO.action_times, ULO.aligned_with, ULO.alternative_for, ULO.antonym,
+                ULO.automatically_proved, ULO.axiom, ULO.check_time, ULO.constructs,
+                ULO.contains, ULO.counter_example_for, ULO.crossrefs, ULO.declaration,
+                ULO.defines, ULO.definition, ULO.deprecated, ULO.derived, ULO.docref,
+                ULO.example, ULO.example_for, ULO.experimental, ULO.external_size,
+                ULO.file, ULO.folder, ULO.formalizes, ULO.function, ULO.generated_by,
+                ULO.hypernym, ULO.hyponym, ULO.implementation_uses,
+                ULO.implementation_uses_implementation_of,
+                ULO.implementation_uses_interface_of, ULO.important, ULO.inductive_on,
+                ULO.inspired_by, ULO.instance_of, ULO.inter_statement,
+                ULO.interface_uses, ULO.interface_uses_implementation_of,
+                ULO.interface_uses_interface_of, ULO.internal_size, ULO.justifies,
+                ULO.last_checked_at, ULO.library, ULO.library_group, ULO.logical,
+                ULO.mutual_block, ULO.name, ULO.nyms, ULO.organizational, ULO.para,
+                ULO.paratype, ULO.phrase, ULO.physical, ULO.predicate, ULO.primitive,
+                ULO.proof, ULO.proposition, ULO.revision, ULO.rule, ULO.same_as,
+                ULO.section, ULO.see_also, ULO.similar_to, ULO.size_properties,
+                ULO.sourceref, ULO.specified_in, ULO.specifies, ULO.statement,
+                ULO.superseded_by, ULO.theorem, ULO.theory, ULO.type, ULO.typedec,
+                ULO.unimportant, ULO.universe, ULO.uses, ULO.uses_implementation,
+                ULO.uses_interface
+        );
+
+        for (final IRI predicate : predicates) {
+            final GraphDB.Operation<Long> operation = (manager, repository, connection) -> {
+                final RepositoryResult<Statement> result = connection.getStatements(null, predicate, null);
+                final Iterator<Statement> iterator = result.iterator();
+
+                long count = 0;
+
+                while (iterator.hasNext()) {
+                    count += 1;
+                    result.next();
+                }
+
+                return count;
+            };
+
+            final long count = GraphDB.execute(operation);
+            System.out.printf("%s - %s\n", count, predicate.toString());
+        }
+    }
+}

src/ulo-storage-endpoint/src/main/java/info/mathhub/uloapi/query/GraphDB.java

 package info.mathhub.uloapi.query;
 
+import info.mathhub.uloapi.config.Config;
 import org.eclipse.rdf4j.repository.Repository;
 import org.eclipse.rdf4j.repository.RepositoryConnection;
 import org.eclipse.rdf4j.repository.RepositoryException;
@@ -48,6 +49,23 @@ public class GraphDB {
         void apply() throws Exception;
     }
 
+    /**
+     * Run an operation on a remote repository. Uses default credentials as defines in the
+     * {@code uloapi.properties} file.
+     *
+     * @param op The operation to execute.
+     * @param <T> The return type of the operation
+     * @return The return value of the operation, i.e. of argument {@code op}.
+     * @throws OperationException If the logic of the operation itself causes some kind of error.
+     * @throws RepositoryException If communication with the remote database fails.
+     */
+    public static <T> T execute(Operation<T> op) {
+        final String serverUrl = Config.serverUrl();
+        final String repositoryName = Config.repository();
+
+        return GraphDB.execute(serverUrl, repositoryName, op);
+    }
+
     /**
      * Run an operation on a remote repository.
      *

src/ulo-storage-endpoint/src/main/resources/uloapi.properties

 info.mathhub.uloapi.config.serverurl=http://rdf:7200
-info.mathhub.uloapi.config.repository=myulo
+info.mathhub.uloapi.config.repository=fckw
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