Data Transformation Engine Type Designer Reference Guide

Chapter 12 - Error Detection and Recovery Error Detection
♦ The data object is valid but contains errors. You indicated that you wanted to
ignore certain errors.
In addition to these conditions, the system can also tell if there is any unknown
data remaining after the card object has been recognized. This can occur if there
really is "junk" at the end. It may also be that enough data was identified to
determine the status of the entire object and the data at the end could not, for
some reason, be determined to have anything to do with the data object.
When a data object exists, the status of that object is determined by validating its
type properties. If an entire data object is an item, it is easy to determine what
the status is: whether it is valid or whether it does not match its item format,
whether its value is not one of the specified restrictions, or whether it is missing
an initiator or terminator. If the source or destination exists and the entire data
object is an item, there is nothing else it could possibly be.
If the type of the entire data object is a group, the status of each component must
be determined. The system uses existence indicators to determine whether a
group component exists. If a component exists, the system can also tell you its
status. If a component is required in another component that exists, the system
will notify you if that required component is missing.
Existence Versus Presence of Components
A component exists if the data object in which it is contained in exists and if the
component takes up space (if there is at least one byte in the data stream
representing that component).
For example,
♦ If a delimiter appears as a placeholder for that component.
♦ If the type of that component has an initiator that distinguishes that
component from any other component that may appear at that position in a
data stream, the component exists if the initiator is there.
♦ If the type of that component is a group with an identifier and all components
up to and including that identifier have been found to be valid.
♦ If the type of the component is an item with a restriction list and one of its
restrictions appear in the data.
♦ If the type of the component is an item with a Padded To length specified and
the item contains at least the number of bytes in the Pad To length.
♦ If the type of an optional component is valid, but the component rule evaluates
to FALSE, the component only exists if there is a syntactic placeholder.
Data may exist, but may not be present. The presence of data is determined by
whether the data has content. The following definitions are used in other parts of
this reference guide: