app:set up /explore/node page

src/ulo-storage-applications/src/main/java/info/mathhub/uloapi/html/Main.java

@@ -18,6 +18,7 @@ public class Main {
         get("/queries", Routes.queries, new FreeMarkerEngine());
         get("/explore", Routes.explore, new FreeMarkerEngine());
         get("/explore/contributor/:contributor", Routes.exploreContributor, new FreeMarkerEngine());
+        get("/explore/node/:base64uri", Routes.exploreNode, new FreeMarkerEngine());
 
         internalServerError(Errors.internalServerError);
         notFound(Errors.notFound);

src/ulo-storage-applications/src/main/java/info/mathhub/uloapi/html/Routes.java

@@ -76,6 +76,21 @@ public class Routes {
         return new ModelAndView(withGlobals(model), "explore_contributor.flt");
     };
 
+    public static final TemplateViewRoute exploreNode = (Request request, Response response) -> {
+        final Query query = Query.getSingleton();
+
+        final String base64uri = request.params("base64uri");
+        final String uri = Base64.decode(base64uri);
+
+        final List<IRI> uses = query.getUses(uri);
+
+        final Map<String, Object> model = new HashMap<>();
+        model.put("uri", uri);
+        model.put("uses", uses);
+
+        return new ModelAndView(withGlobals(model), "explore_node.flt");
+    };
+
     /**
      * Add some global values we always need to argument {@code model}.
      *

src/ulo-storage-applications/src/main/java/info/mathhub/uloapi/query/IRIs.java

+package info.mathhub.uloapi.query;
+
+import org.eclipse.rdf4j.model.IRI;
+import org.eclipse.rdf4j.model.ValueFactory;
+import org.eclipse.rdf4j.model.impl.SimpleValueFactory;
+
+public class IRIs {
+    private IRIs() {}
+
+    /**
+     * Create an {@link IRI} from argument {@code value}.
+     *
+     * @param value The argument to turn into an {@link IRI}.
+     * @return An {@link IRI} that contains argument {@code value}.
+     */
+    public static IRI fromString(String value) {
+        if (value == null) {
+            throw new NullPointerException("argument value must not be null");
+        }
+
+        final ValueFactory valueFactory = SimpleValueFactory.getInstance();
+        return valueFactory.createIRI(value);
+    }
+}

src/ulo-storage-applications/src/main/java/info/mathhub/uloapi/query/Query.java

@@ -167,4 +167,34 @@ public class Query {
 
         return GraphDB.execute(this.serverUrl, this.repository, operation);
     }
+
+    /**
+     * Return a list of works used by another given node.
+     *
+     * @param nodeuri The URI of the node.
+     */
+    public List<IRI> getUses(String nodeuri) {
+        final GraphDB.Operation<List<IRI>> operation = (manager, repository, connection) -> {
+            final Set<IRI> uses = new HashSet<>();
+            final IRI subject = IRIs.fromString(nodeuri);
+
+            final RepositoryResult<Statement> result = connection.getStatements(subject, ULO.uses, null);
+
+            for (final Statement statement : result) {
+                final Value object = statement.getObject();
+
+                if (!(object instanceof IRI)) {
+                    log.warn("found object that is not an IRI");
+                    continue;
+                }
+
+                final IRI asIri = (IRI) object;
+                uses.add(asIri);
+            }
+
+            return new ArrayList<>(uses);
+        };
+
+        return GraphDB.execute(this.serverUrl, this.repository, operation);
+    }
 }

src/ulo-storage-applications/src/main/resources/spark/template/freemarker/explore_node.flt

+<#ftl output_format="HTML" auto_esc=false>
+<#setting url_escaping_charset='UTF-8'>
+
+<#include "base.flt">
+
+<#macro page_title>
+    Explore Node
+</#macro>
+
+<#macro page_main>
+
+    <h2>Explore Node</h2>
+
+    <h3>URI</h3>
+
+    <ul>
+        <li>
+            <code>${uri}</code>
+        </li>
+    </ul>
+
+    <h3>Node uses...</h3>
+
+    <ul>
+        <#list uses as use>
+            <li>
+                <code>${use}</code>
+            </li>
+        </#list>
+    </ul>
+</#macro>
+
+<@display_page/>