=== modified file 'dhis-2/dhis-api/src/main/java/org/hisp/dhis/dataelement/DataElementCategory.java'
--- dhis-2/dhis-api/src/main/java/org/hisp/dhis/dataelement/DataElementCategory.java	2012-03-27 17:38:48 +0000
+++ dhis-2/dhis-api/src/main/java/org/hisp/dhis/dataelement/DataElementCategory.java	2012-04-11 07:45:09 +0000
@@ -35,6 +35,7 @@
 import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlRootElement;
 import org.hisp.dhis.common.BaseIdentifiableObject;
 import org.hisp.dhis.common.Dxf2Namespace;
+import org.hisp.dhis.common.IdentifiableObject;
 import org.hisp.dhis.common.view.DetailedView;
 import org.hisp.dhis.common.view.ExportView;
 import org.hisp.dhis.concept.Concept;
@@ -179,4 +180,27 @@
     {
         this.concept = concept;
     }
+
+    @Override
+    public void mergeWith( IdentifiableObject other )
+    {
+        super.mergeWith( other );
+
+        if ( other.getClass().isInstance( this ) )
+        {
+            DataElementCategory dataElementCategory = (DataElementCategory) other;
+
+            concept = dataElementCategory.getConcept() == null ? concept : dataElementCategory.getConcept();
+
+            for ( DataElementCategoryOption dataElementCategoryOption : dataElementCategory.getCategoryOptions() )
+            {
+                categoryOptions.add( dataElementCategoryOption );
+
+                if ( dataElementCategoryOption.getCategory() == null )
+                {
+                    dataElementCategoryOption.setCategory( this );
+                }
+            }
+        }
+    }
 }

=== modified file 'dhis-2/dhis-api/src/main/java/org/hisp/dhis/dataelement/DataElementCategoryCombo.java'
--- dhis-2/dhis-api/src/main/java/org/hisp/dhis/dataelement/DataElementCategoryCombo.java	2012-03-27 17:38:48 +0000
+++ dhis-2/dhis-api/src/main/java/org/hisp/dhis/dataelement/DataElementCategoryCombo.java	2012-04-11 07:45:09 +0000
@@ -36,6 +36,7 @@
 import org.hisp.dhis.common.BaseIdentifiableObject;
 import org.hisp.dhis.common.CombinationGenerator;
 import org.hisp.dhis.common.Dxf2Namespace;
+import org.hisp.dhis.common.IdentifiableObject;
 import org.hisp.dhis.common.view.DetailedView;
 import org.hisp.dhis.common.view.ExportView;
 
@@ -243,4 +244,27 @@
     {
         this.optionCombos = optionCombos;
     }
+
+    @Override
+    public void mergeWith( IdentifiableObject other )
+    {
+        super.mergeWith( other );
+
+        if ( other.getClass().isInstance( this ) )
+        {
+            DataElementCategoryCombo dataElementCategoryCombo = (DataElementCategoryCombo) other;
+
+            categories.addAll( dataElementCategoryCombo.getCategories() );
+
+            for ( DataElementCategoryOptionCombo dataElementCategoryOptionCombo : dataElementCategoryCombo.getOptionCombos() )
+            {
+                optionCombos.add( dataElementCategoryOptionCombo );
+
+                if ( dataElementCategoryOptionCombo.getCategoryCombo() == null )
+                {
+                    dataElementCategoryOptionCombo.setCategoryCombo( this );
+                }
+            }
+        }
+    }
 }

=== modified file 'dhis-2/dhis-api/src/main/java/org/hisp/dhis/dataelement/DataElementCategoryOption.java'
--- dhis-2/dhis-api/src/main/java/org/hisp/dhis/dataelement/DataElementCategoryOption.java	2012-03-27 17:38:48 +0000
+++ dhis-2/dhis-api/src/main/java/org/hisp/dhis/dataelement/DataElementCategoryOption.java	2012-04-11 07:45:09 +0000
@@ -37,6 +37,7 @@
 import org.hisp.dhis.common.BaseIdentifiableObject;
 import org.hisp.dhis.common.BaseNameableObject;
 import org.hisp.dhis.common.Dxf2Namespace;
+import org.hisp.dhis.common.IdentifiableObject;
 import org.hisp.dhis.common.view.DetailedView;
 import org.hisp.dhis.concept.Concept;
 
@@ -125,6 +126,22 @@
     }
 
     // -------------------------------------------------------------------------
+    // Logic
+    // -------------------------------------------------------------------------
+
+    public void addCategoryOptionCombo( DataElementCategoryOptionCombo dataElementCategoryOptionCombo )
+    {
+        categoryOptionCombos.add( dataElementCategoryOptionCombo );
+        dataElementCategoryOptionCombo.getCategoryOptions().add( this );
+    }
+
+    public void removeCategoryOptionCombo( DataElementCategoryOptionCombo dataElementCategoryOptionCombo )
+    {
+        categoryOptionCombos.remove( dataElementCategoryOptionCombo );
+        dataElementCategoryOptionCombo.getCategoryOptions().remove( this );
+    }
+
+    // -------------------------------------------------------------------------
     // Getters and setters
     // -------------------------------------------------------------------------
 
@@ -173,4 +190,23 @@
     {
         this.categoryOptionCombos = categoryOptionCombos;
     }
+
+    @Override
+    public void mergeWith( IdentifiableObject other )
+    {
+        super.mergeWith( other );
+
+        if ( other.getClass().isInstance( this ) )
+        {
+            DataElementCategoryOption dataElementCategoryOption = (DataElementCategoryOption) other;
+
+            concept = dataElementCategoryOption.getConcept() == null ? concept : dataElementCategoryOption.getConcept();
+            category = category != null ? category : dataElementCategoryOption.getCategory();
+
+            for ( DataElementCategoryOptionCombo dataElementCategoryOptionCombo : dataElementCategoryOption.getCategoryOptionCombos() )
+            {
+                addCategoryOptionCombo( dataElementCategoryOptionCombo );
+            }
+        }
+    }
 }

=== modified file 'dhis-2/dhis-api/src/main/java/org/hisp/dhis/dataelement/DataElementCategoryOptionCombo.java'
--- dhis-2/dhis-api/src/main/java/org/hisp/dhis/dataelement/DataElementCategoryOptionCombo.java	2012-03-27 17:38:48 +0000
+++ dhis-2/dhis-api/src/main/java/org/hisp/dhis/dataelement/DataElementCategoryOptionCombo.java	2012-04-11 07:45:09 +0000
@@ -37,6 +37,7 @@
 import org.hisp.dhis.common.BaseIdentifiableObject;
 import org.hisp.dhis.common.BaseNameableObject;
 import org.hisp.dhis.common.Dxf2Namespace;
+import org.hisp.dhis.common.IdentifiableObject;
 import org.hisp.dhis.common.view.DetailedView;
 import org.hisp.dhis.common.view.ExportView;
 
@@ -325,4 +326,18 @@
     {
         this.categoryOptions = categoryOptions;
     }
+
+    @Override
+    public void mergeWith( IdentifiableObject other )
+    {
+        super.mergeWith( other );
+
+        if ( other.getClass().isInstance( this ) )
+        {
+            DataElementCategoryOptionCombo dataElementCategoryOptionCombo = (DataElementCategoryOptionCombo) other;
+
+            categoryCombo = categoryCombo != null ? categoryCombo : dataElementCategoryOptionCombo.getCategoryCombo();
+            categoryOptions.addAll( dataElementCategoryOptionCombo.getCategoryOptions() );
+        }
+    }
 }