extension of multi package to compartment added when necessary

converter-sbml/src/main/java/lcsb/mapviewer/converter/model/sbml/compartment/SbmlCompartmentExporter.java

@@ -11,6 +11,7 @@ import org.sbml.jsbml.ext.layout.BoundingBox;
 import org.sbml.jsbml.ext.layout.CompartmentGlyph;
 import org.sbml.jsbml.ext.layout.Dimensions;
 import org.sbml.jsbml.ext.layout.Point;
+import org.sbml.jsbml.ext.multi.MultiCompartmentPlugin;
 
 import lcsb.mapviewer.converter.model.sbml.SbmlElementExporter;
 import lcsb.mapviewer.converter.model.sbml.SbmlExtension;
@@ -38,6 +39,11 @@ public class SbmlCompartmentExporter extends SbmlElementExporter<Compartment, or
     }
     //for now we don't have this information - needed for validation
     result.setConstant(false);
+    if (isExtensionEnabled(SbmlExtension.MULTI)) {
+      MultiCompartmentPlugin multiExtension = new MultiCompartmentPlugin(result);
+      multiExtension.setIsType(false);
+      result.addExtension("multi", multiExtension);
+    }
     return result;
   }