Bad and good examples of traits

controller_with_trait.php

<?php

trait Serialization
{
    protected function serialize($data, $groups = null)
    {
        $context = new SerializationContext($groups);

        return $this->serializer->serialize($data, $context);
    }
}


class ControllerWithTrait
{
    use Serialization;

    protected $serializer;

    public function __construct(Serializer $serializer)
    {
        $this->serializer = $serializer;
    } 

    public function withTraits()
    {
        $data = ['some', 'data'];
        
        return $this->serialize($data, 'my_group');
    }
}

controller_without_traits.php

<?php 

class Controller
{
    protected $serializer;

    public function __construct(Serializer $serializer)
    {
        $this->serializer = $serializer;
    } 

    public function withoutTraits()
    {
        $data = ['some', 'data'];
        $context = new SerializationContext('my_group');

        return $this->serializer->serialize($data, $context);
    }
}

serializer.php

<?php

class SerializerContext
{
    private $serializationGroups = [];

    public function __construct($groups = null)
    {
        $groups = is_null($groups) ? 'default' : $groups;
        $groups = is_array($groups) ? $groups : [$groups];
        $this->serializationGroups = $groups;
    }
}

class Serializer
{
    // ...
    public function serialize($data, $context)
    {
        // do something with data. Context stores settings for our work
    }
    // ...
}