package org.apache.struts2.showcase.conversion
public class EnumTypeConverter extends StrutsTypeConverter
{
//old methods..
//new method to convert map contents to Strings..
@Override
public String[] convertToStrings(Map context, Object o)
{
int j=0;
Strings[] s;
List l = (List) o;
String result ="<";
for (Iterator i = l.iterator(); i.hasNext(); )
{
s[j++]=i.next();
}
return s;
}
//...other methods..
}
FWIW
Martin--
----- Original Message -----
From: "Jeromy Evans" <[EMAIL PROTECTED]>
To: "Struts Users Mailing List" <user@struts.apache.org>
Sent: Tuesday, February 19, 2008 5:23 PM
Subject: Re: Type conversion questions
> Daniel Baldes wrote:
> > Hello,
> >
> > I have a web form where you can, generally speaking, assign objects to
> > groups. This is done via a multiple select box which displays an
> > object's name and uses its ID property as value.
> >
> > So, usually, my action would get back a String array containing the
> > IDs of the selected objects. I want the framework to load the
> > corresponding objects from the database and pass them as a Collection
> > to my action's setObjects(Collection<Object> objects) method, so that
> > my action doesn't have to deal with loading objects.
> >
> > So I wrote a type converter. The "convertFromString" method takes the
> > String array with the IDs, determines the target element type using
> > ObjectTypeDeterminer, loads the objects and returns them in a
> > collection. In this direction - form to action - it works quite well.
> >
>
> Great. I've never tried this myself. I suppose you run the risk of
> some performance penalties doing it here (eg. select n+1 due to
> iteration) and the conversion error exception is probably not ideal, but
> otherwise I'm impressed.
> > Now my questions:
> >
> > 1. extending StrutsTypeConverter forces me to implement String
> > convertToString(Map context, Object o). I think there is no common
> > sense way of converting a collection back to a String in this context.
> > It would, maybe, make sense to convert it to a String[]. But what I
> > actually want is to have access to the unconverted collection in the
> > JSP. This might seem strange from some point of view, and I could live
> > without it, but is there a way to do this? Example:
> >
> > <s:select multiple="true"
> > name="myObjects"
> > list="myObjects" listKey="id" listValue="name" />
> >
> > This way I could use getMyObjects() for displaying my objects and
> > setMyObjects() for setting them (using only their IDs).
> >
>
> It does really follow the intended contract of the interface, but I
> don't see why convertFromString can't return a different view of the
> object than convertToString. Have you tried it? This effectively gives
> you the "databinding" feature of ASP.net (which I personally cringe at,
> but can't argue with how productive it is to work with)
> >
> > 2. Is there a way to define a type converter application wide, like
> > "always use this type converter for setting types which are subclasses
> > of X" and "for setting types which are Collection<subclass-of-X>"?
> > This way I could define the type converter once for all
> > persistence-capable classes.
> >
> classpath:xwork-converters.properties allows you to define global
> converters by class name. You may be able to the the element_ feature
> for collections.
> Otherwise visitor validation will have to do
>
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