Dynamic array creation

[None]

Dynamic array creation

Hi all... here's a good one for you...

I have a situation where I have some bean, and I need to populate an
array field in it... here's the problem... I do not know the element
type of the array before runtime.

Now, I've been planning on using Commons Beanutils, since the rest of
this particular app does (it's doing a lot of introspection of the
beans and such).

So, here's the question... can anyone figure out a way to dynamically
create an array at runtime? What I mean is, I want to do the
followig:

PropertyUtils.setProperty(obj, fieldName,
((List)fieldValues).toArray());

So, I want to set the field named by fieldName on the bean instance
referenced by obj, and I want to do it by taking the fieldValues List
and converting it to an array. Now, I can do:

PropertyUtils.setProperty(obj, fieldName,
((List)fieldValues).toArray(new String[0]));

....and that's great, except that I don't know until runtime that the
field of the bean is of type String, it could be anything else. So,
how can I dynamically do the equivalent of the new String[0] is really
the question?

FYI, I don't really care if this is done with Beanutils, but I think
that's probably the logical course of action. Any ideas? Thanks all!

[Oliver Wong]

"None" <no**@none.com> wrote in message
news:3b********************************@4ax.com...

Dynamic array creation

Hi all... here's a good one for you...

I have a situation where I have some bean, and I need to populate an
array field in it... here's the problem... I do not know the element
type of the array before runtime.

Now, I've been planning on using Commons Beanutils, since the rest of
this particular app does (it's doing a lot of introspection of the
beans and such).

So, here's the question... can anyone figure out a way to dynamically
create an array at runtime? What I mean is, I want to do the
followig:

PropertyUtils.setProperty(obj, fieldName,
((List)fieldValues).toArray());

So, I want to set the field named by fieldName on the bean instance
referenced by obj, and I want to do it by taking the fieldValues List
and converting it to an array. Now, I can do:

PropertyUtils.setProperty(obj, fieldName,
((List)fieldValues).toArray(new String[0]));

...and that's great, except that I don't know until runtime that the
field of the bean is of type String, it could be anything else. So,
how can I dynamically do the equivalent of the new String[0] is really
the question?

FYI, I don't really care if this is done with Beanutils, but I think
that's probably the logical course of action. Any ideas? Thanks all!

Use the Array.newInstance(Class, int) method:

http://java.sun.com/j2se/1.5.0/docs/...g.Class,%20int)

(note that there's a close parenthesis at the end that's part of this URL).

- Oliver