=== modified file 'dhis-2/dhis-api/src/main/java/org/hisp/dhis/node/AbstractNode.java'
--- dhis-2/dhis-api/src/main/java/org/hisp/dhis/node/AbstractNode.java	2014-06-04 18:33:34 +0000
+++ dhis-2/dhis-api/src/main/java/org/hisp/dhis/node/AbstractNode.java	2014-06-05 09:09:03 +0000
@@ -28,13 +28,11 @@
  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE
  */
 
+import com.google.common.collect.ImmutableList;
 import com.google.common.collect.Lists;
-import com.google.common.collect.Maps;
-import org.hisp.dhis.node.exception.DuplicateNodeException;
 import org.hisp.dhis.node.exception.InvalidTypeException;
 
 import java.util.List;
-import java.util.Map;
 
 /**
  * @author Morten Olav Hansen <mortenoh@gmail.com>
@@ -49,7 +47,7 @@
 
     private String comment;
 
-    private Map<String, Node> children = Maps.newHashMap();
+    private List<Node> children = Lists.newArrayList();
 
     protected AbstractNode( String name, NodeType nodeType )
     {
@@ -75,6 +73,30 @@
     }
 
     @Override
+    public boolean is( NodeType type )
+    {
+        return type.equals( nodeType );
+    }
+
+    @Override
+    public boolean isSimple()
+    {
+        return is( NodeType.SIMPLE );
+    }
+
+    @Override
+    public boolean isComplex()
+    {
+        return is( NodeType.COMPLEX );
+    }
+
+    @Override
+    public boolean isCollection()
+    {
+        return is( NodeType.COLLECTION );
+    }
+
+    @Override
     public String getNamespace()
     {
         return namespace;
@@ -104,12 +126,7 @@
             return null;
         }
 
-        if ( children.containsKey( child.getName() ) )
-        {
-            throw new DuplicateNodeException();
-        }
-
-        children.put( child.getName(), child );
+        children.add( child );
         return child;
     }
 
@@ -123,20 +140,9 @@
     }
 
     @Override
-    public Node getChild( String name )
-    {
-        if ( children.containsKey( name ) )
-        {
-            return children.get( name );
-        }
-
-        return null;
-    }
-
-    @Override
     public List<Node> getChildren()
     {
-        return Lists.newArrayList( children.values() );
+        return ImmutableList.copyOf( children );
     }
 
     @Override

=== modified file 'dhis-2/dhis-api/src/main/java/org/hisp/dhis/node/Node.java'
--- dhis-2/dhis-api/src/main/java/org/hisp/dhis/node/Node.java	2014-06-04 18:33:34 +0000
+++ dhis-2/dhis-api/src/main/java/org/hisp/dhis/node/Node.java	2014-06-05 09:09:03 +0000
@@ -51,6 +51,37 @@
     NodeType getType();
 
     /**
+     * @param type Type to check for
+     * @return True if node is of this type
+     */
+    boolean is( NodeType type );
+
+    /**
+     * Helper that checks if node is of simple type, useful to checking if
+     * you are allowed to add children to this node.
+     *
+     * @return true if type is simple
+     * @see org.hisp.dhis.node.NodeType
+     */
+    boolean isSimple();
+
+    /**
+     * Helper that checks if node is of complex type.
+     *
+     * @return true if type is complex
+     * @see org.hisp.dhis.node.NodeType
+     */
+    boolean isComplex();
+
+    /**
+     * Helper that checks if node is of collection type.
+     *
+     * @return true if type is collection
+     * @see org.hisp.dhis.node.NodeType
+     */
+    boolean isCollection();
+
+    /**
      * Namespace for this node. Not all serializers support this, and its up to the
      * NodeSerializer implementation to decide what to do with this.
      *
@@ -84,14 +115,6 @@
     <T extends Node> void addChildren( Iterable<T> children );
 
     /**
-     * Returns child with name, or null if it doesn't exist.
-     *
-     * @param name Name to search for
-     * @return A node with that name if it exists, or null
-     */
-    Node getChild( String name );
-
-    /**
      * Get all child notes associated with this node. Please note that the returned list is a copy
      * of the internal list, and changes to the list will not be reflected in the node.
      *