I've always struggled with type conversion of lists and I'd appreciate a
more experienced brain to help me out.
Consider the following multiple select box:
<s:select multiple="true" name="users.id" list="users" listKey="id"
listValue="username" value="%{centre.users.{user.id}}" />
As per the documentation, "name your element people.name and the
framework will understand that it should create a new Person object for
each selected item and set its name accordingly."
This works correctly, without even needing an
MyAction-conversion.properties file if my action has:
private List<UserImpl> users;
However, because I usually work with interfaces (and Spring-inject my
dependencies), to have my action implementation-agnostic I want to have.
private List<User> users;
where User is an interface and UserImpl implements User.
However, as soon as the List (and getter/setters) are changed to use
User, the type conversion no longer works, yielding:
2011-05-17 11:17:13,554 WARN [CommonsLogger.java:60] : Error setting
expression 'users.id' with value '[Ljava.lang.String;@13d344e7'
ognl.OgnlException: Error converting given String values for Collection.
[org.springframework.beans.factory.BeanCreationException: Error creating
bean with name 'com.itclinical.iwrs.model.User': Could not resolve
matching constructor (hint: specify index/type/name arguments for simple
parameters to avoid type ambiguities)]
This happens even if I have a UserEditAction-conversion.properties with:
#KeyProperty_users=id
#Element_users=iw.persist.model.UserImpl
#CreateIfNull_users=true
So, how can one use the automatic type conversion when your list is
defined for an interface?
Thank you in advance,
Miguel Almeida
