Graphml export

timbuctoo-instancev4/src/main/java/nl/knaw/huygens/timbuctoo/server/TimbuctooV4.java

@@ -84,6 +84,7 @@
 import nl.knaw.huygens.timbuctoo.v5.dataset.DataSetRepository;
 import nl.knaw.huygens.timbuctoo.v5.dropwizard.DataSetFactoryManager;
 import nl.knaw.huygens.timbuctoo.v5.dropwizard.contenttypes.CsvWriter;
+import nl.knaw.huygens.timbuctoo.v5.dropwizard.contenttypes.GraphMlWriter;
 import nl.knaw.huygens.timbuctoo.v5.dropwizard.contenttypes.GraphVizWriter;
 import nl.knaw.huygens.timbuctoo.v5.dropwizard.contenttypes.JsonLdWriter;
 import nl.knaw.huygens.timbuctoo.v5.dropwizard.contenttypes.JsonWriter;
@@ -282,7 +283,8 @@ public void run(TimbuctooConfiguration configuration, Environment environment) t
       new CsvWriter(),
       new JsonLdWriter(),
       new JsonWriter(),
-      new GraphVizWriter()
+      new GraphVizWriter(),
+      new GraphMlWriter()
     );
 
     final PaginationArgumentsHelper argHelper = new PaginationArgumentsHelper(configuration.getCollectionFilters());

timbuctoo-instancev4/src/main/java/nl/knaw/huygens/timbuctoo/v5/dropwizard/contenttypes/GraphMlWriter.java

@@ -0,0 +1,19 @@
+package nl.knaw.huygens.timbuctoo.v5.dropwizard.contenttypes;
+
+import nl.knaw.huygens.timbuctoo.v5.serializable.serializations.GraphMlSerialization;
+import javax.ws.rs.Produces;
+
+@Produces(GraphMlWriter.MIME_TYPE)
+public class GraphMlWriter extends SerializerWriter {
+
+  public static final String MIME_TYPE = "text/graphml";
+
+  public GraphMlWriter() {
+    super(GraphMlSerialization::new);
+  }
+
+  @Override
+  public String getMimeType() {
+    return MIME_TYPE;
+  }
+}

timbuctoo-instancev4/src/main/java/nl/knaw/huygens/timbuctoo/v5/serializable/serializations/GraphMlSerialization.java

@@ -0,0 +1,69 @@
+package nl.knaw.huygens.timbuctoo.v5.serializable.serializations;
+
+import java.io.IOException;
+import java.io.OutputStream;
+import java.io.PrintWriter;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import nl.knaw.huygens.timbuctoo.v5.serializable.SerializableResult;
+import nl.knaw.huygens.timbuctoo.v5.serializable.serializations.base.CollectionsOfEntitiesSerialization;
+
+public class GraphMlSerialization extends CollectionsOfEntitiesSerialization {
+
+  private final PrintWriter writer;
+  private int countEdge = 1;
+
+  public GraphMlSerialization(OutputStream outputStream) throws IOException {
+    writer = new PrintWriter(outputStream);
+  }
+
+  public void serialize(SerializableResult serializableResult) throws IOException {
+    super.serialize(serializableResult);
+    Map<String, Integer> entityIds = new HashMap<>();
+    AtomicInteger nodeCounter = new AtomicInteger();
+    writeHeader();
+    for (Map<String, AggregatedEntity> entities : allEntities.values()) {
+      for (Map.Entry<String, AggregatedEntity> entity : entities.entrySet()) {
+        Integer nodeId = entityIds.computeIfAbsent(entity.getKey(), k -> nodeCounter.incrementAndGet());
+        writer.println("    <node id=\"node" + nodeId + "\">");
+        writer.println("      <data key=\"" + entity.getKey() + "\">" + entity.getValue() + "</data>");
+        writer.println("      <data key=\"label\">" + entity.getKey() + "</data>");
+        writer.println("    </node>");
+        for (Map.Entry<String, Set<String>> relation : entity.getValue().relations.entrySet()) {
+          for (String otherNodeUri : relation.getValue()) {
+            Integer otherNodeId = entityIds.computeIfAbsent(otherNodeUri, k -> nodeCounter.incrementAndGet());
+            writer.println("    <edge id=\"e" + countEdge  + "\" source=\"node" +
+                nodeId  + "\" target=\"node" + otherNodeId + "\">");
+            writer.println("      <data key=\"label\">" + relation.getKey() + "</data>");
+            writer.println("    </edge>");
+            countEdge++;
+          }
+        }
+      }
+    }
+    writeFooter();
+    writer.flush();
+    writer.close();
+  }
+
+
+  protected void writeHeader() {
+    String header = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n" +
+      "<graphml xmlns=\"http://graphml.graphdrawing.org/xmlns\"\n" +  
+      "    xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\"\n" +
+      "    xsi:schemaLocation=\"http://graphml.graphdrawing.org/xmlns\n" +
+      "        http://graphml.graphdrawing.org/xmlns/1.0/graphml.xsd\">";
+    writer.println(header);
+    writer.println("  <graph id=\"G\" edgedefault=\"directed\">");
+  }
+
+  protected void writeFooter() {
+    writer.println("  </graph>");
+    String footer = "</graphml>";
+    writer.println(footer);
+  }
+
+}