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From Ted Husted <>
Subject Re: [DynaBean] a couple of other existing projects...
Date Thu, 03 Jan 2002 13:20:44 GMT
Paulo Gaspar wrote:
> For such use it makes sense to have a specialized DynaClass and some
> helpers,

Agreed. I'm just thinking that the first thing I will do with a DynaBean
is define a number of standard field or column helpers, that would
correlate to the columns or fields in a database. 

Since this will be a common idea, we might want to consider a companion
package to the DynaBean that defined these helpers. This could save us,
and dozens of others, from each implementing our own, all with the same

There are are finite number of column types supported by the JDBC, so
I'm thinking there could be a toolkit for generating these and rolling
them into a DynaBean. 

Since any value can be represented as a String, such a helper might
include a String buffer along with its native object, and could be very
useful in ferrying input from the Web tier (which is String based) to
the Business tier (which often needs native values). So each column
helper would have a getXXX form and a getXXXString form. There may also
be a setXXXBuffer form to enter data for later validation, and then a
trigger for the valiation/conversion routine.

Elsewhere in this thread, I believe it's been suggested that an
application might actually end up with two DynaBean definations, one
String, one native. This often happens in Struts applications today. I'm
just thinking that the leverage a DynaBean give us, makes a standard
column helper package is an attractive idea.

In practice, there would probably be domain-level validators/converters
in the column helpers, and a model-level validator/convereter in the
DynaBean itself. The idea being, for example, that first I make sure the
datum could be a username or password (not too short, et cetera), and
then I check to see if it actually registered as such. 

-- Ted Husted, Husted dot Com, Fairport NY USA.
-- Building Java web applications with Struts.
-- Tel +1 585 737-3463.
-- Web

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