Re: Does FM support varargs or arrays in method calls?

Yeah I tried 2.4 about 2 months ago and it wasn't stable enough at the time.  If a backport of that feature to 2.3.x isn't too much work that would be cool.

For now, I only have 3 places that call this method, and at most they'll pass in 5 parameters.  So I guess temporarily I can put up with this crap,

        public <E extends Entity> List<E> list(Class<E> entityClass,
                        String queryName, List<Object> queryParams) {
                switch (queryParams.size()) {
                        case 0:
                                return entityManager.findByNamedQuery(entityClass, queryName);
                        case 1:
                                return entityManager.findByNamedQuery(entityClass, queryName,
                                                queryParams.get(0));
                        case 2:
                                return entityManager.findByNamedQuery(entityClass, queryName,
                                                queryParams.get(0), queryParams.get(1));
                        case 3:
                                return entityManager.findByNamedQuery(entityClass, queryName,
                                                queryParams.get(0), queryParams.get(1), queryParams
                                                                .get(2));
                        case 4:
                                return entityManager.findByNamedQuery(entityClass, queryName,
                                                queryParams.get(0), queryParams.get(1), queryParams
                                                                .get(2), queryParams.get(3));
                        case 5:
                                return entityManager
                                                .findByNamedQuery(entityClass, queryName, queryParams
                                                                .get(0), queryParams.get(1),
                                                                queryParams.get(2), queryParams.get(3),
                                                                queryParams.get(4));
                        default:
                                throw new IllegalArgumentException(
                                                "More than 5 query parameters is currently not supported.");
                }
        }

That is really really bad, but as far as I can tell it's my only option at this point.  Any other ideas short of that mess or a backport?  I can't help but wonder if there isn't a feature of the language for this.  Collections should be autoboxed! :P

A google search led me here http://constc.blogspot.com/2007/04/calling-java-vararg-methods-from.html
Sounds like fun!  If I get bored this afternoon I'm gonna look in your svn to see how that all works, quite an interesting concept with for sure a very challenging implementation.

Thanks again,
John


-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Daniel Dekany
Sent: Thursday, December 06, 2007 6:22 AM
To: Attila Szegedi
Cc: FreeMarker-user
Subject: Re: [FreeMarker-user] Does FM support varargs or arrays in method calls?

Thursday, December 6, 2007, 9:43:28 AM, Attila Szegedi wrote:

> We've added vararg handling to 2.4 (which is not yet released).
> There's currently no vararg handling in 2.3. Can you try using 2.4?
> You can grab the latest 2.4 build from here:

That I don't recommend, as it is not stable.

> - go to <http://freemarker.org:8085/browse/FM-TRUNK/latest>
> - click "Artifacts" tab
> - download the freemarker.jar behind the "Library" link
>
> Failing that, I can backport vararg handling to 2.3.x branch.
>
> Attila.
>
> On 2007.12.05., at 23:17, Newman, John W wrote:
>
>> Hi,
>>
>> This is interesting, I might be in trouble here - hopefully I'm just
>> missing something.   Consider this,
>>
>> class WrappedObject  {
>>      public <E extends Entity> java.util.List<E>
>> findByNamedQuery(Class<E> entityClass,
>>                  String query, Object... queryParams) {
>>            return entityManager.findByNamedQuery(entityClass, query,
>> queryParams);
>>      }
>> }
>>
>>
>> class EntityManager  {
>>      public <E extends Entity> java.util.List<E>
>> findByNamedQuery(Class<E> entityClass,
>>                  String query, Object... queryParams) {
>>            // do hibernate stuff here
>>      }
>> }
>>
>>
>> [#assign results = wrappedObject.findByNamedQuery(${class},
>> "findByFirstAndLastName", ["John", "Smith"]) /]
>>
>> Should work right?
>>
>> : freemarker.template.TemplateModelException: No signature of method
>> findByNamedQuery matches
>> (java
>> .lang.Class,java.lang.String,freemarker.ext.beans.SequenceAdapter)
>>
>> If I forget about the varargs and change the wrapped objects method
>> to use Object[] queryParams, I get the exact same exception.
>> However if I change it to List<Object>, ["John", "Smith"] matches
>> the rule, and the method gets invoked.
>>
>> That's ok, but I can't change the API of the EntityManager class -
>> we're stuck with varargs there.  So,
>>
>>
>> class WrappedObject  {
>>      public <E extends Entity> java.util.List<E>
>> findByNamedQuery(Class<E> entityClass,
>>                  String query, List<Object> queryParams) {
>>            return entityManager.findByNamedQuery(entityClass, query,
>> queryParams == null ? queryParams : queryParams.toArray(new
>> Object[queryParams.size()]));
>>      }
>> }
>>
>> I really thought that would work.  Unfortunately, all it does is
>> pass in 1 parameter to entityManager's method, an Object[] - not
>> Object, Object.  Interesting.  Any ideas?  Is there different syntax
>> for arrays & lists?
>>
>> Any help is greatly appreciated.
>>
>> Thanks,
>> john
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>
> Attila.
>
> --
> home: http://www.szegedi.org
> weblog: http://constc.blogspot.com
>
>
>
>
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--
Best regards,
 Daniel Dekany


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