Grails command objects and input name values

Question

I have a form where I have to have the input elements ordered specifically. So my form looks something like this:

<input type="text" name="name"/>
<select name="contacts.first">...</select>
<select name="contacts.second">...</select>
...

I have a command object that I'm trying to use to validate this form. However, I can't seem to get it to map correctly. My command object looks like this:

@Validatable
class MyCommand {
     def name
     def contacts

     static constraints = { /* ... */ }
}

My controller action looks like:

def update = { MyCommand cmd -> 
    if (cmd.validate()) {
         /* ... */
    }
}

When I look at cmd.contacts, it's null. If I name each select just contacts instead of contacts.first, it is an array of values as expected, but I did not want to depend on the browser to make sure these items are in a specific order. Any suggestions to making this work? The correct order is crucial.

Answer 1

Original idea: http://stateyourbizness.blogspot.com/2009/02/binding-to-collection-fields-on-command.html

So for your command object you could use:

import org.apache.commons.collections.FactoryUtils;
import org.apache.commons.collections.ListUtils;

class MyCommand {
    def name
    List contacts = ListUtils.lazyList([], FactoryUtils.constantFactory(''))
    /* ... */
}

And have your html look like:

<input type="text" name="name"/>
<select name="contacts[0]">...</select>
<select name="contacts[1]">...</select>