Re: How to set the name parameter on a multiple s:select

[Dale Newfield]

On May 30, 2013, at 5:42 AM, Miguel Almeida  wrote:
> That's an alternative, yes. I do tend to prefer having the model objects
> in my actions though, to keep the number of objects to a minimum - it
> makes more sense to have a List objects than an Integer[]
> ids, but maybe that's personal preference.

Of course you eventually want objects, but remember this is a web application, 
and the only thing the browser is supplying are ids.  It's up to your action to 
bridge that difference.

> I'm not sure where the ambiguity is. Take the following request
> parameters:
> entity.entity2List[0].entity3.id=10
> entity.entity2List[1].entity3.id=20
> 
> There is no ambiguity in how the Object should be populated - one
> entity, which has two Entity2 on the entity2List object: the first
> entity2 has an Entity3.id=10 and the second Entity2 has an
> Entity3.id=20.

Bzzt.  That doesn't do what you want, and it requires more data than your 
browser is providing.  That doesn't set the entity3 object with id 10 on the 
first entity2, rather it assumes there already are two entity2 objects on 
entity, that those already have entity3 objects on the them and then it just 
changes the ids!  If you model he ui on the browser page differently you can 
get the parameters above, but the nature of a multi select is that you're 
getting back multiple (unordered) values each with the same request parameter 
name.

Sounds like what you want are multiple single selects, so that each can have a 
different description on the page (identifying the entity2 for which this 
selection is being made), and allowing each to have a distinct index in its 
parameter name.  You'll still have the first problem above, though--you want to 
load the entity3 with the provided id and set that object on the corresponding 
entity2.  You can probably use the params-prepare-params stack pattern to help 
you, but you'll still need to have the parameter name be to just to properties 
on the action that your prepare knows to hydrate on prepare, then the body of 
the action just has to wire up the objects.

-Dale
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Re: How to set the name parameter on a multiple s:select

[Miguel Almeida]

Thanks for the feedback Dale.
A couple of thoughts below.
On Wed, 2013-05-29 at 08:18 -0400, Dale Newfield wrote:

> I would have a setter on my action class that takes an array of ids.  Then 
> the action does the appropriate lookups, and sets the hydrated objects on the 
> appropriate models.

That's an alternative, yes. I do tend to prefer having the model objects
in my actions though, to keep the number of objects to a minimum - it
makes more sense to have a List objects than an Integer[]
ids, but maybe that's personal preference.

> You do recognize that the data you provided is ambiguous, though, right?  
> Nothing you stated is sufficient to know *which* entity2 objects should be 
> set on entity, just which entity3 objects you want those entity2 objects to 
> have.  In fact, if you don't happen to get a number of entity3 ids that 
> matches the number of entity2s on entity, you've left yourself no way of 
> knowing how to proceed. (Remember, all you get is a (potentially unordered) 
> list of ids from the form submission, not tuples.)

I'm not sure where the ambiguity is. Take the following request
parameters:
entity.entity2List[0].entity3.id=10
entity.entity2List[1].entity3.id=20

There is no ambiguity in how the Object should be populated - one
entity, which has two Entity2 on the entity2List object: the first
entity2 has an Entity3.id=10 and the second Entity2 has an
Entity3.id=20.
In fact, this request works as expected (as evidenced by the test case
[1]). The challenge is to create an s:select that generates that request
parameters!

Miguel

[1] Unit Test snippet

request.setParameter("entity.entity2List[0].entity3.id", "2");
request.setParameter("entity.entity2List[1].entity3.id", "11");

createAction("/example/Conversion.action");

executeProxy();

Entity entity = ((TypeConversionAction) action).getEntity();
assertNotNull(entity);
assertNotNull(entity.getEntity2List());
assertEquals(2, entity.getEntity2List().size());

assertEquals(2, 
entity.getEntity2List().get(0).getEntity3().getId());
assertEquals(11, 
entity.getEntity2List().get(1).getEntity3().getId());

> 
> -Dale
> 
> On May 29, 2013, at 6:27 AM, Miguel Almeida  wrote:
> 
> > Dear all,
> > 
> > Imagine you have the following scenario:
> > - a property in your action: private Entity entity;
> > 
> > - Entity has a List entity2List
> > - Entity2 has a Entity3 entity3
> > 
> > Now, you need an s:select with multiple="true" to populate entity3. This
> > corresponds to having a request in the form
> > entity.entity2List[n].entity3.id (n=0,1,2...depending on how many items
> > are selected).
> > 
> > Question: how should the name parameter of the s:select be like to
> > achieve this?
> > 
> > Me and Lukasz  have tried the following without success (meaning
> > entity.entity2List has is empty):
> >  > name="%{entity.entity2List[].entity3.id}" list="#someList" listKey="id"
> > listValue="code"/>
> >  > name="entity.entity2List[].entity3.id" list="#someList" listKey="id"
> > listValue="code"/>
> > 
> > 
> > Thank you for your help!
> > 
> > Miguel Almeida
> > 
> 
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