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/PrintableIRI.java

+package info.mathhub.uloapi.html;
+
+import org.eclipse.rdf4j.model.IRI;
+
+import java.util.List;
+import java.util.stream.Collectors;
+
+/**
+ * Wrapper around {@link IRI} that provides additional
+ * methods for use in Freemarker templates.
+ */
+public class PrintableIRI implements IRI {
+    private final IRI original;
+
+    public PrintableIRI(IRI original) {
+        this.original = original;
+    }
+
+    /**
+     * Convert a list of {@link IRI} to {@link PrintableIRI}.
+     */
+    public static List<PrintableIRI> convert(List<IRI> originals) {
+        return originals.stream().map(PrintableIRI::new).collect(Collectors.toList());
+    }
+
+    @Override
+    public String toString() {
+        return this.original.toString();
+    }
+
+    @Override
+    public String getNamespace() {
+        return this.original.getNamespace();
+    }
+
+    @Override
+    public String getLocalName() {
+        return this.original.getLocalName();
+    }
+
+    @Override
+    public String stringValue() {
+        return this.original.stringValue();
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        return this.original.equals(o);
+    }
+
+    @Override
+    public int hashCode() {
+        return this.original.hashCode();
+    }
+
+    public String toBase64() {
+        return Base64.encode(this.toString());
+    }
+}

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

@@ -67,7 +67,7 @@ public class Routes {
         final Query query = Query.getSingleton();
 
         final String contributor = request.params("contributor");
-        final List<IRI> contributions = query.getContributions(contributor);
+        final List<PrintableIRI> contributions = PrintableIRI.convert(query.getContributions(contributor));
 
         final Map<String, Object> model = new HashMap<>();
         model.put("contributor", contributor);
@@ -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<PrintableIRI> uses = PrintableIRI.convert(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_contributor.flt

@@ -16,7 +16,9 @@
     <ul>
         <#list contributions as contribution>
             <li>
-                <code>${contribution}</code>
+                <a href="/explore/node/${contribution.toBase64()?url}">
+                    <code>${contribution}</code>
+                </a>
             </li>
         </#list>
     </ul>

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>${uri}</code>
+        </li>
+    </ul>
+
+    <h3>Node uses...</h3>
+
+    <ul>
+        <#list uses as use>
+            <li>
+                <a href="/explore/node/${use.toBase64()?url}">
+                    <code>${use}</code>
+                </a>
+            </li>
+        </#list>
+    </ul>
+</#macro>
+
+<@display_page/>