Null

SYNTAX

null

The null value corresponds to one of three different scenarios:

1. the absence of an attribute in a Ruletest Input pane or request message
2. the absence of data for an attribute in a Ruletest (the value zero counts as data)
3. a business object (supplied by an external application) that has an instance variable of null

A null value is different from an empty String (for String data types) or zero for numeric data types. An empty String is represented in a Ruletest as [] -- open then close square brackets. Any attribute value, including any empty strings, may be reset to null in a Ruletest by right-clicking the attribute and choosing Set to null. Mandatory attributes (property set in the Vocabulary) may not have a null value.

The Literals row in the table of Summary Table of Vocabulary Usage Restriction applies. No special exceptions.

The following Rulesheet uses null to test for the existence of a real value in decimal1, and assign a value to boolean1 as a result.

A sample Ruletest provides four examples of decimal1. Input and Output panels are illustrated below. Posted messages are not shown.