<?php

namespace Metadata\Driver;

final class DriverChain implements AdvancedDriverInterface
{
private $drivers;

public function __construct(array $drivers = array())
{
$this->drivers = $drivers;
}

public function addDriver(DriverInterface $driver)
{
$this->drivers[] = $driver;
}

public function loadMetadataForClass(\ReflectionClass $class)
{
foreach ($this->drivers as $driver) {
if (null !== $metadata = $driver->loadMetadataForClass($class)) {
return $metadata;
}
}

return null;
}

/**
* {@inheritDoc}
*/
public function getAllClassNames()
{
$classes = array();
foreach ($this->drivers as $driver) {
if (!$driver instanceof AdvancedDriverInterface) {
throw new \RuntimeException(
sprintf(
'Driver "%s" must be an instance of "AdvancedDriverInterface" to use '.
'"DriverChain::getAllClassNames()".',
get_class($driver)
)
);
}
$driverClasses = $driver->getAllClassNames();
if (!empty($driverClasses)) {
$classes = array_merge($classes, $driverClasses);
}
}

return $classes;
}
}