One to many mapping in mule data mapper - mule

Question

I have an input xml and it has only one Telephone child element,
<ContactMethod>
<Telephone type="fax">
<Number>String</Number>
<Extension>String</Extension>
</Telephone>
</ContactMethod>
But my output XML has multiple Telephone child element,
<ContactMethod>
<Telephone type="fax">
<Number>String</Number>
<Extension>String</Extension>
</Telephone>
<Telephone type="fax">
<Number>String</Number>
<Extension>String</Extension>
</Telephone>
</ContactMethod>
I want to map from input element Number to output Number and also Extension element.
I can't change the schema because it is globally used.
I don't see any options to map using Element Mapping.
And I tried using adding Rule to the ContactMethod element, but no luck.
......
Above I is just example I asked. I need one to many mapping idea in datamapper.
See attached image, that is my actual requirement. Look at the Disclosure/CandidateDisclosure elements in source and destination
My source is XML and target is JSON, but the actual logic I need is similar for all the structures ..

Answer 1

I am maintaining a project which use DataMapper and faced the same issue. To solve it I add Java Transformer (you can use Groovy or other scripting languages) after DataMapper to group the one-to-many relationship.
Following is the pseudo code:
provide empty telpMap
foreach telpXml which is extracted from src/payload {
key = telpXml.get("#type");
if (telpMap.containsKey(key)) {
List number = telpMap.get(key).get("Number");
number.addAll(telpXml.get("Number"));
List extension = telpMap.get(key).get("Extension");
extension.addAll(telpXml.get("Extension"));
} else {
telpMap.put(key, telpXml);
}
}
return telpMap.values();