Advanced User-Defined Functions 

Use

Advanced user-defined functions can access more than just individual field values. Instead, you can import a complete context or an entire queue for a field as an array before your function is called. This enables you, for example, to perform calculations on all field values of a context as well as to divide up the contexts themselves further by inserting context changes.

Integration

When the instance for a source structure is parsed, a message mapping works with queues.

There is a queue for each hierarchy level. A queue can have the following entries:

Possible Queue Entries

Value	Meaning
(empty string)	This is a queue for a structure field. In the queue there is an entry with an empty string each time the field appears in the XML instance. In the example above there is such a queue for <A /> and <root />.
(string)	Value of a value field
ResultList.CC	Constant that shows a context change
ResultList.SUPPRESS	Constant that causes a field and its subnode to be ignored during processing
(empty context)	Context that does not contain any values (see the graphic below).

You can create special structure mappings by adding or removing context changes. The standard functions SplitByValue() and removeContexts() work by this principle.

See also: Structure Mappings by Setting the Context.

The following basic rule applies for nested structures: The number of contexts of a queue must be the same as the number of values (empty strings) of the upper-level queue.

Features

Advanced user-defined functions can import either just one context into the input arrays, or complete queues. You define this using the execution type in the function properties of a function:

Working with Contexts or Queues

Execution Type	Implications
All Values of Context	Advanced functions that only import one context do not have an identifiable context change. You can of course insert a context change into the results list.
All Values of Queue	Since one or more entire queues are imported in this case, this option is more memory-intensive and is not suitable for very large messages.

The input arrays do not contain the context change at the start and end of the context (or the queue). These context changes are implicitly always available and cannot be identified or deleted from the user-defined function.