8
I am writing a system in PHP that has to write to three persistence layers:
- One web service
- Two databases (one mysql one mssql)
The reason for this is legacy systems and cannot be changed.
I am wanting to use the DataMapper pattern and I am trying to establish the best way to achieve what I want. I have an interface like follows:
<?php
$service = $factory->getService()->create($entity);
?>
Below is some contrived and cut down code for brevity:
<?php
class Post extends AbstractService
{
protected $_mapper;
public function create(Entity $post)
{
return $this->_mapper->create($post);
}
}
class AbstractMapper
{
protected $_persistence;
public function create(Entity $entity)
{
$data = $this->_prepareForPersistence($entity);
return $this->_persistence->create($data);
}
}
?>
My question is that because there are three persistence layers, there will also therefore likely be a need for three mappers for each. I'd like a clean design pattern inspired interface to make this work.
I see it as having three options:
- Inject three mappers into the Service and call create on each
- $_mapper is an array/collection and it iterates through them calling create on each
- $_mapper is actually a container object that acts as a further proxy and calls create on each
Something strikes me as wrong with each of these solutions and would appreciate any feedback/recognised design patterns that might fit this.