bundles/org.simantics.db.layer0/src/org/simantics/db/layer0/request/SingleActiveModel.java

   1 package org.simantics.db.layer0.request;
   2
   3 import java.util.Collection;
   4
   5 import org.simantics.db.ReadGraph;
   6 import org.simantics.db.Resource;
   7 import org.simantics.db.common.request.ResourceRead;
   8 import org.simantics.db.common.utils.NameUtils;
   9 import org.simantics.db.exception.DatabaseException;
  10 import org.simantics.db.exception.NoSingleResultException;
  11
  12 /**
  13  * Returns the active model or null if no single active model is available.
  14  */
  15 public class SingleActiveModel extends ResourceRead<Resource> {
  16
  17     public SingleActiveModel(Resource project) {
  18         super(project);
  19     }
  20
  21     @Override
  22     public Resource perform(ReadGraph graph) throws DatabaseException {
  23         Collection<Resource> actives = graph.syncRequest(new ActiveModels(resource));
  24         if (actives.size() == 1)
  25             return actives.iterator().next();
  26
  27         if (actives.size() == 0)
  28                 throw new NoSingleResultException("There are no active models.");
  29
  30         throw new NoSingleResultException("There are many active models: " + NameUtils.getSafeName(graph, actives));
  31
  32     }
  33
  34 }