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diff --git a/bundles/org.simantics.browsing.ui.model/src/org/simantics/browsing/ui/model/children/RelationChildRule.java b/bundles/org.simantics.browsing.ui.model/src/org/simantics/browsing/ui/model/children/RelationChildRule.java
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index 000000000..0e5b21b92
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+++ b/bundles/org.simantics.browsing.ui.model/src/org/simantics/browsing/ui/model/children/RelationChildRule.java
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+/*******************************************************************************
+ * Copyright (c) 2010, 2011 Association for Decentralized Information Management in
+ * Industry THTH ry.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *     VTT Technical Research Centre of Finland - initial API and implementation
+ *******************************************************************************/
+package org.simantics.browsing.ui.model.children;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+
+import org.simantics.browsing.ui.model.tests.Test;
+import org.simantics.db.ReadGraph;
+import org.simantics.db.Resource;
+import org.simantics.db.exception.DatabaseException;
+import org.simantics.db.exception.NoInverseException;
+
+/**
+ * A child rule that says that there is exactly one child node whose content 
+ * is equal to the content of the parent.
+ * @author Hannu Niemistö
+ */
+public class RelationChildRule implements ChildRule {
+
+    Resource relation;
+    Test test;
+    
+    public RelationChildRule(Resource relation, Test test) {
+        this.relation = relation;
+        this.test = test;
+    }
+    
+    @Override
+    public Collection<?> getChildren(ReadGraph graph, Object parent) throws DatabaseException {
+        Collection<Resource> result = graph.getObjects((Resource)parent, relation);
+        if(test != null) {
+            ArrayList<Resource> filtered = new ArrayList<Resource>(result.size());
+            for(Resource r : result)
+                if(test.test(graph, r))
+                    filtered.add(r); 
+            result = filtered;
+        }
+        return result;
+    }
+
+    @Override
+    public Collection<?> getParents(ReadGraph graph, Object child)
+            throws DatabaseException {
+        try {
+            if(child instanceof Resource) {
+                Resource inverse = graph.getInverse(relation);            
+                return graph.getObjects((Resource)child, inverse);
+            }
+        } catch(NoInverseException e) {
+        }   
+        return Collections.emptyList();
+    }
+    
+    @Override
+    public boolean isCompatible(Class<?> contentType) {
+        return contentType.equals(Resource.class);
+    }
+}