Setting an option in an option element using a Java bean

[Bob]

How can a particular option in an option element on a JSP be set using a getXXX()
method of a Java bean?

[Larne Pekowsky]

Bob <robert.byrnes@transcore.com> wrote:
>How can a particular option in an option element on a JSP be set
>using a getXXX() method of a Java bean?

Unfortunately there's no easy, single-tag, sort of thing that will do
this for you. You have to check each of your options, and when you
find the currently chosen option add a SELECTED parameter. Something
like this:

<jsp:useBean class="ColorBean" id="which"/>

<select name="color">
<option <%= which.getColor().equals("Red") ? "SELECTED" : "" %>>Red
<option <%= which.getColor().equals("Green") ? "SELECTED" : "" %>>Green
<option <%= which.getColor().equals("Blue") ? "SELECTED" : "" %>>Blue
</select>


The stuff in the expression tags <%= %> are little chunks of Java
code. In Java something like

expression1 ? expression2 : expression3

means "If expression1 is true use expression2, otherwise use
expression3." So the first clause:

which.getColor().equals("Red") ? "SELECTED" : ""

means "call getColor() on the 'which' bean, if it is equal to "Red"
then add "SELECTED" to the page, otherwise add an empty string. So if
which.getColor() is Red, this will result in:

<option SELECTED>Red

which is exactly what we want.

Admittedly this is a little verbose, and requires a fair bit of
repeated code. I think it should be possible to create a custom tag
or two that would hide some of this complexity, but I haven't seen any
examples yet.

- Larne