New generator that creates a URI from several fields, otherwise a UUID

[ymark]

Implement a new generator that will create a URI from a given set of fields. If any of these fields does not exist then it will create a UUID for the node.

<ROOT>
	<COIN>
		<ID>id1</ID>
		<CODE> code1</CODE>
	<COIN>
	<COIN>
		<ID>id2</ID>
		<CODE></CODE>
	<COIN>
</ROOT>

In the above example, the generator should re-use the values from the elements ID and CODE for generating a URI. In the first case it will construct a URI, n the second case it will construct a UUID.