SpecBasedFactoryTrait.php

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<?php
namespace Wikimedia\Leximorph\Traits;
 
use Psr\Log\LoggerInterface;
use Psr\Log\NullLogger;
use UnexpectedValueException;
use Wikimedia\ObjectFactory\ObjectFactory;
 
trait SpecBasedFactoryTrait {
 
    protected string $langCode;
 
    protected ?LoggerInterface $logger = null;
 
    protected array $singletons = [];
 
    abstract protected function getSpecMap(): array;
 
    abstract protected function getSpecArgs( array $spec, LoggerInterface $logger ): array;
 
    protected function createFromSpec( string $class ) {
        if ( isset( $this->singletons[$class] ) ) {
            $cached = $this->singletons[$class];
 
            return $cached;
        }
 
        $specs = $this->getSpecMap();
        if ( !isset( $specs[$class] ) ) {
            throw new UnexpectedValueException( "Class not registered: $class" );
        }
 
        $spec = $specs[$class];
        $logger = $this->logger ?? new NullLogger();
 
        $args = $this->getSpecArgs( $spec, $logger );
        if ( !empty( $spec['args'] ) && is_array( $spec['args'] ) ) {
            $args = array_merge( $args, $spec['args'] );
        }
 
        $objectSpec = [
            'class' => $class,
            'args' => $args,
        ];
 
        $instance = ObjectFactory::getObjectFromSpec( $objectSpec );
 
        if ( !$instance instanceof $class ) {
            throw new UnexpectedValueException(
                "Expected instance of $class, got " . get_class( $instance )
            );
        }
 
        $this->singletons[$class] = $instance;
 
        return $instance;
    }
}