Create a Custom Backend Adapter

To create a custom backend adapter, you need to follow three steps:

1. Create a new PHP class for your custom backend adapter;
2. Register it as a service tagged pimcore.backend_power_tools.alternative_element_trees.data_object.adapter;
3. Add the adapter class to the mapping.

Create the PHP Class

You must define getAdapterValues function that returns the adapter's value while extending \Pimcore\Bundle\BackendPowerToolsBundle\Adapter\AlternativeElementTree\DataObject\AbstractObjectAdapter:

<?php 

namespace App\Adapter\AlternativeElementTree; 

class CustomAdapter extends \Pimcore\Bundle\BackendPowerToolsBundle\Adapter\AlternativeElementTree\DataObject\AbstractObjectAdapter
{
    // start implementing 
    protected function getAdapterValues(): array
    {
        ...
    }
}

Tag the Service

Without the tag the adapter is not found and no value is shown:

services:
  App\Adapter\AlternativeElementTree\CustomAdapter:
    autowire: true
    tags:
      - { name: 'pimcore.backend_power_tools.alternative_element_trees.data_object.adapter' }

Add the Adapter Type to the Mapping

The last step is to add the adapter type to the mapping. This can be done in the config.yaml of your bundle.

pimcore_backend_power_tools:
  pimcore_alternative_object_trees:
    adapters:
      input: #= the datatype of the corresponding class field
        frontend: SimpleValueAdapter
        backend: App\Adapter\AlternativeElementTree\CustomAdapter