Overriding a Mapping Table Entry

If the mapper chooses the wrong transformer for a specific source and target type pair, you can override it by decorating the correct transformer and adding it to the mapping table.

note

Note that in this case, we don't decorate the transformer to replace the original transformer in the dependency injection container. Instead, we are "duplicating" an existing transformer, override its type mapping information, and putting it earlier in the mapping table.

Suppose you have a YourObject class and a YourObjectDto class, but the mapper does not use the desired transformer for the job. You can fix it by decorating the correct transformer like this:

use Rekalogika\Mapper\Transformer\AbstractTransformerDecorator;
use Rekalogika\Mapper\Transformer\ObjectToObjectTransformer;
use Rekalogika\Mapper\Transformer\Contracts\TypeMapping;
use Rekalogika\Mapper\Util\TypeFactory;

class OverrideTransformer extends AbstractTransformerDecorator
{
    public function __construct(ObjectToObjectTransformer $transformer)
    {
        parent::__construct($transformer);
    }

    public function getSupportedTransformation(): iterable
    {
        yield new TypeMapping(
            TypeFactory::objectOfClass(YourObject::class),
            TypeFactory::objectOfClass(YourObjectDto::class),
        );
    }
}

With the above example, when the source is YourObject and the target is YourObjectDto, the mapper will now choose ObjectToObjectTransformer instead of choosing from the rest of the mapping table.