----- Original Message -----
From: "Jonas Bj�rnerstedt" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Wednesday, May 30, 2001 4:55 PM
Subject: Bean philosophy
> Having just switched from Perl to Java web development, perhaps I am missing
> something fundamental. Being new to the forum, I also don't know if this
> issue has been discussed before.
>
> It strikes me as odd that in beans in general and ActionForm beans in
> particular that properties are set by setXxx and getXxx methods.
> Spontaneously you would think that a bean should have a get("name") and a
> set("name", "value") to retreive or save attributes in a Hashtable in the
> bean.
>
> Reusability is one of the nice things about beans. With the current design
> however, if I want to retreive the properties set in a bean in a reusable
> way, I have to go the roundabout way of using reflection. My question is: In
> what sense is a bean more than than a Hashtable?
In a Been, you can use a Hashtable to save your attributes, but you don't have to use
a Hashtable. I normaly don't. Because I know which attributes to expect, I implement
these as fields in the Bean, and save the values in these. I know that a Hashtable has
an expected constant-time on the get and put operations, but it is only expected time.
With fields, I know that I have a constant-time operations, besides I'm sure that Java
won't have to do some bookkeeping behind my back to insure the proper working of a
Hashtable.
Besides that, you can do a lot of other interesting stuff in the get/set methods, like
accessing other objects, if you don't want to store the attributes in your Been.
I have also been programming Perl, and I know that Hashtables are a nice thing. But
remember, that a Java class is a proper class, and not just a hashtable in desguise.
But of course there are situations, where what you propose is very usefull.
/Anders.
