MRM Custom wire format: NULL handling

An explicit null is identified by a specific value that identifies an element as being null.

The Boolean Null Value can be specified at the message set level, and applies to the Boolean elements of all messages that are defined in that message set. The null value of all other element types can be specified individually for each element.

CWF supports the representation of null values by using the Encoding Null and Encoding Null Value element properties. Together, this information controls how null values are handled by the MRM parser.

The Encoding Null property can be set to one of four values:

NullLogicalValue

The Encoding Null Value property is interpreted as a logical value. Therefore, if its value is set to 0, for example, both 0 and 0.00 are interpreted as null values.

NullLiteralValue

The Encoding Null Value property is interpreted as a string value. Therefore, the value of the element in the bit stream must match exactly the value that is specified to be interpreted as a null value.

NullPadFill

Used for fixed-length elements. On output, any element with a null value is padded to the appropriate length with the specified padding character.

NullLiteralFill

The Encoding Null Value property is interpreted as a single character string value. Therefore, each character of the value of the element in the bit stream must match exactly the character value specified to be interpreted as a null value.