mongodb-odm-docs-dash/Doctrine ODM.docset/Contents/Resources/Documents/_sources/reference/custom-collections.rst.txt

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.. _custom_collection:
Custom Collections
==================
.. note::
This feature was introduced in version 1.1
By default, Doctrine uses ``ArrayCollection`` implementation of its ``Collection``
interface to hold both embedded and referenced documents. That collection may then
be wrapped by a ``PersistentCollection`` to allow for change tracking and other
persistence-related features.
.. code-block:: php
<?php
use Doctrine\Common\Collections\ArrayCollection;
/** @Document */
class Application
{
// ...
/**
* @EmbedMany(targetDocument="Section")
*/
private $sections;
public function __construct()
{
$this->sections = new ArrayCollection();
}
// ...
}
For most cases this solution is sufficient but more sophisticated domains could use
their own collections (e.g. a collection that ensures its contained objects are sorted)
or to simply add common filtering methods that otherwise would otherwise be added to
owning document's class.
Custom Collection Classes
-------------------------
.. note::
You may want to check `malarzm/collections <https://github.com/malarzm/collections>`_
which provides alternative implementations of Doctrine's ``Collection`` interface and
aims to kickstart development of your own collections.
Using your own ``Collection`` implementation is as simple as specifying the
``collectionClass`` parameter in the ``@EmbedMany`` or ``@ReferenceMany`` mapping
and ensuring that your custom class is initialized in the owning class' constructor:
.. code-block:: php
<?php
use Doctrine\Common\Collections\ArrayCollection;
/** @Document */
class Application
{
// ...
/**
* @EmbedMany(
* collectionClass="SectionCollection"
* targetDocument="Section"
* )
*/
private $sections;
public function __construct()
{
$this->sections = new SectionCollection();
}
// ...
}
If you are satisfied with ``ArrayCollection`` and only want
to sprinkle it with some filtering methods, you may just extend it:
.. code-block:: php
<?php
use Doctrine\Common\Collections\ArrayCollection;
class SectionCollection extends ArrayCollection
{
public function getEnabled()
{
return $this->filter(function(Section $s) {
return $s->isEnabled();
});
}
}
Alternatively, you may want to implement the whole class from scratch:
.. code-block:: php
<?php
use Doctrine\Common\Collections\Collection;
class SectionCollection implements Collection
{
private $elements = array();
public function __construct(array $elements = array())
{
$this->elements = $elements;
}
// your implementation of all methods interface requires
}
Taking Control of the Collection's Constructor
----------------------------------------------
By default, Doctrine assumes that it can instantiate your collections in same
manner as an ``ArrayCollection`` (i.e. the only parameter is an optional PHP
array); however, you may want to inject additional dependencies into your
custom collection class(es). This will require you to create a
`PersistentCollectionFactory implementation <https://github.com/doctrine/mongodb-odm/blob/master/lib/Doctrine/ODM/MongoDB/PersistentCollection/PersistentCollectionFactory.php>`_,
which Doctrine will then use to construct its persistent collections.
You may decide to implement this class from scratch or extend our
``AbstractPersistentCollectionFactory``:
.. code-block:: php
<?php
use Doctrine\ODM\MongoDB\PersistentCollection\AbstractPersistentCollectionFactory;
use Symfony\Component\EventDispatcher\EventDispatcherInterface;
final class YourPersistentCollectionFactory extends AbstractPersistentCollectionFactory
{
private $eventDispatcher;
public function __construct(EventDispatcherInterface $eventDispatcher)
{
$this->eventDispatcher = $eventDispatcher;
}
protected function createCollectionClass($collectionClass)
{
switch ($collectionClass) {
case SectionCollection::class:
return new $collectionClass(array(), $this->eventDispatcher);
default:
return new $collectionClass;
}
}
}
The factory class must then be registered in the ``Configuration``:
.. code-block:: php
<?php
$eventDispatcher = $container->get('event_dispatcher');
$collFactory = new YourPersistentCollectionFactory($eventDispatcher);
$configuration = new Configuration();
// your other config here
$configuration->setPersistentCollectionFactory($collFactory);