[TYPO3-mvc] Casting objects

[Xavier Perseguers]

Hi Sebastian,

> that's an interesting use-case! We wanted to write some mixin-support 
> somewhen in time, so that you can add functionality and behavior to 
> existing domain objects. However, we wanted to prevent overriding methods.
> 
> Would the above approach solve your problem as well?

As long as the findOneBy... and other related methods can be extended to 
return the new class, it is what I need because in fact I don't want to 
override existing methods, just add some functionality.

> For me it would be very helpful if you could explain your exact use-case 
> for the "casting".

Well, first of all I use Extbase naming conventions and partly base 
classes but I cannot use it fully because when I last tried to use it 
more than before (about 2 months ago) there was no support for my use 
case, namely modeling a legacy MSSQL database where there is no "uid", 
"pid", and the rest columns and I already had written my own 
"DataMapper" specifically for this case. Note that for the time being, I 
still don't persist anything, I just read data but I'll have too in a 
near future and that the rest of TYPO3 runs on standard MySQL.

Now, I made this business model in a dedicated extension and then add it 
as a dependency in my other extensions, may it be frontend plugins or 
backend modules.

Last week I decided to make a statistic frontend plugin with graphs 
(using sav_jpgraph) or plain-old "tables" of data. I use views in MSSQL 
to cleanly "prepare" data as I try as much as possible to use TYPO3 
standard query methods (with DBAL/AdoDB in this case) but the SQL parser 
is so "dumb" that this is a clear no go to create even "simple" queries 
involving subqueries:

SELECT ... FROM (SELECT ... FROM ... WHERE ...)

Thus my use case is that I wanted statistics to be put into my domain 
model (because it's related to the objects I have there) but still 
without "polluting" it for all extensions. This is why I extended the 
domain in a "statistics" extension does contains the extended domain 
model as well as related FE plugins/BE modules.

I attached the helper class I wrote yesterday to let me cast my domain 
objects. I basically now have this for instance for a Person and 
PersonRepository I would have to use with statistics:

class Tx_MyExtStatistics_Domain_Model_Person extends 
Tx_MyExtBusiness_Domain_Model_Person {

     public function getStatistics() {
        // code
     }
}

class Tx_MyExtStatistics_Domain_Model_PersonRepository extends 
Tx_MyExtBusiness_Domain_Model_PersonRepository {


public function findOneByUid($uid) {
     $person = parent::findOneByUid($uid);
     return 
Tx_MyExtStatistics_Helpers_Helper::castToClass('Tx_MyExtStatistics_Domain_Model_Person', 
$person);
     }
}

As said, Tx_MyExtStatistics_Helpers_Helper is attached to this message.

One more thing, I used some home-made lazy loading that did not yet 
exist in Extbase (and I guess still does not). For instance if my person 
is part of a company, I have a companyId in the database for the person 
table. But I do not want every time to have the related company object 
recreated when I get a person. This is why I have a setter on my person 
object to set the companyId but I have a getter for a company object, 
not for the companyId (this later explains part of the code you find in 
my castToClass static method:

public function setCompanyId($id) {
     $this->companyId = $id;
     // Reset lazy loading
     $this->company = null;
}

public function getCompany() {
     if (!$this->company) {
         $companyRepository = 
t3lib_div::makeInstance('Tx_MyExtBusiness_Domain_Model_CompanyRepository');
         /* @var ... */

         $this->company = 
$companyRepository->findOneByUid($this->companyId);
         $this->_cleanProperties['company'] = $this->company;
     }
     return $this->company;
}

-- 
Xavier Perseguers
DBAL-Member

http://xavier.perseguers.ch/en/tutorials/typo3.html