How to compute a bind variable from another?

Question

I am trying to create a View Criteria that has the following View Object Where Clause:
(UPPER(LOCALE) = UPPER(:LocaleCode) ) OR (UPPER(LOCALE) = UPPER(SUBSTR(:LocaleCode,1,2)))
In other words, I have a bind variable called LocaleCode, and I want to return all rows that either match the LocaleCode exactly (first part of the Where Clause), or match the first 2 characters of the LocaleCode value (second part of Where Clause).
I can't seem to figure out any way to do this straight-up using the UI for a View Criteria - there doesn't seem to be a "substring" operator when adding an item to the clause.
So, my thought was to create a second bind variable (e.g. "LocaleCode2") that was computed from the first bind variable (LocaleCode). This new bind variable would contain the first 2 characters from LocaleCode. I could then have the Where Clause be:
(UPPER(LOCALE) = UPPER(:LocaleCode) ) OR (UPPER(LOCALE) = UPPER(:LocaleCode2))
My problem is that when I define the LocaleCode2 bind variable, I see the option to set it to an Expression, but I can't seem to figure out how to build an expression that refers to another bind variable.
So, my questions are:
1. How can I have a bind variable expression refer to another bind variable (e.g. "LocaleCode2 = substring(:LocaleCode,1,2)" or something)?
2. Is there a better way to do this altogether? (What I'm trying to do is set up a view criteria for a lookup table that will return rows that match a passed-in locale exactly (language and country), or just on the 'language' part (first 2 characters).)
Thanks!

Answer 1

I think that bind variable accessors in the VO class is what you need. You can override the getter method of the bind variable "LocaleCode2" in order to return the first 2 chars from the bind variable "LocaleCode". Have a look at this blog post for details:
http://jdeveloperandadf.blogspot.com/2011/03/custom-java-bind-variable-in-where.html
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