Removing Logic / Dynamic logic

Question

Hello all... this is something I have been thinking about for a few weeks and every once and a while I get inspired to see if I can find a simple solution to a rather annoying (but not critical) problem I am having with a bit of code... and in fact... I run into this more than a few times a year (so hell... maybe there's a design pattern out there somewhere...)
Anyway... here's the deal.
I have an EJB that accepts a WDDX string, which I deserialize into a Hashtable (very basic)...
Then I loop through the Hashtable looking at the keys and in this case I build a dynamic SQL statement based on the keys that are present in the Hashtable.
So I have a bit of code that looks like this:
if (key.equalsIgnoreCase("foo")) {
    if (sqlStatement.length() == 0)
        sqlStatement.append("where foo = '" + hash.get(key) + "' ");
    else
        sqlStatement.append("and foo = '" + hash.get(key) + "' ");
}Of course the above is a very simple example... sometimes I have to look at the value as well...
Basically... my code gets HUGE! I mean... if I have to check for 20 or so keys... that gets to be a bit crazy... and I hate having to scroll through that much code :)
So, what I am wondering is... is there a design pattern... technique... method... black magic/black box trick to make this logic more dynamic? What I have been thinking is if I could have a configuration file-like construct... almost like a rules file or something similar to that.
Any hints, tips, tricks, advice, swift kick in the backside for asking something that is probably very obvious... would be greatly appreciate.
./dave

Answer 1

If you know the keys that you're looking for can't you
use an array? For Example - put the keys into a
string[] :
private String[] keys = new String[] {"aaa", "bbb",
"ccc", "ddd", "eee", "foo", "ggg", "hhh", "iii"};
... snipped ...
Heh.. thanks! I actually started doing that, but it became as big of a mess as my original concept because... and I know I didn't state this in my example... that I may have to do a bit more complex logic on a key I have in a hash... like if a key is of a certain value... i have to append a String variable so that I can do a certain outter-right join as part of the query I'm building...
Here's an actual example (snipped from my EJB)
else if (key.equals("SELECTYEAR")) {
    if (criteria.length() == 0)
        criteria.append("WHERE v.model_yr = '"+value+"' ");
    else
        criteria.append("AND v.model_yr = '"+value+"' ");
    ordIDJoin = "AND o.ord_id = oi.ord_id";
    configIDJoin = "AND oi.veh_config_id = v.veh_config_id";
else if (key.equals("ORD_STAT_CD"))
    if (value.indexOf(LIST_SEPARATOR) > 0)
        if (criteria.length() == 0)
            criteria.append("WHERE o.ord_stat_cd IN ("+value+") ");
        else
            criteria.append("AND o.ord_stat_cd IN ("+value+") ");
    else
         if (criteria.length() == 0)
            criteria.append("WHERE o.ord_stat_cd = "+value+" ");
         else
            criteria.append("AND o.ord_stat_cd = "+value+" ");So... now (I think) you can see why I need something that can handle a bit more complexity when deciding how to append my sql statement StringBuffer
Thanks for responding! :)
./dave