First, define a hidden form field that uses a default expression to call the Java class by not including any Display class in the field definition:
<Field name=’jobGrade’> <Default> <invoke name=’getJobGrade’ class=’com.waveset.custom.DatabaseAccessor’> <ref>waveset.accountId</ref> </invoke> </Default> </Field> </Derivation> |
Default expressions are evaluated only if the view does not contain a value for the attribute jobGrade. Once the default expression has been run, the result is stored in jobGrade, and the expression is not run again.