has( $id ) ) {
$this->set( $id );
}
$instance = $this->instances[$id];
return $this->resolve( $instance );
}
/**
* Sets an entry of the container by its identifier
*
* @param string $id
* @param object|null $instance
*
* @return void
*/
public function set( string $id, object $instance = null ): void {
if ( $instance === null ) {
$instance = $id;
}
$this->instances[$id] = $instance;
}
/**
* Returns true if the container can return an entry for the given identifier.
* Returns false otherwise.
*
* `has($id)` returning true does not mean that `get($id)` will not throw an exception.
* It does however mean that `get($id)` will not throw a `NotFoundExceptionInterface`.
*
* @param string $id Identifier of the entry to look for.
*
* @return bool
*/
public function has( string $id ): bool {
return isset( $this->instances[$id] );
}
/**
* Resolves the service object by its name.
*
* @param string $class_name
*
* @throws DependencyHasNoDefaultValueException
* @throws DependencyIsNotInstantiableException
* @throws ReflectionException|Exception
*
* @return object
*/
public function resolve( string $class_name ): object {
if ( ! class_exists( $class_name ) ) {
throw new Exception( "Class: {$class_name} does not exist" );
}
$reflection_class = new ReflectionClass( $class_name );
if ( ! $reflection_class->isInstantiable() ) {
throw new DependencyIsNotInstantiableException( "Class: {$class_name} is not instantiable" );
}
if ( null === $reflection_class->getConstructor() ) {
return $reflection_class->newInstance();
}
$parameters = $reflection_class->getConstructor()->getParameters();
$dependencies = $this->build_dependencies( $parameters );
return $reflection_class->newInstanceArgs( $dependencies );
}
/**
* Builds the dependencies for the given parameters.
*
* @param ReflectionParameter[] $parameters
*
* @throws ReflectionException
* @throws DependencyHasNoDefaultValueException
*
* @return array
*/
public function build_dependencies( array $parameters ): array {
$dependencies = [];
foreach ( $parameters as $parameter ) {
$dependency = $parameter->getType() ? $parameter->getType()->getName() : null;
if ( is_null( $dependency ) ) {
if ( $parameter->isDefaultValueAvailable() ) {
$dependencies[] = $parameter->getDefaultValue();
} else {
throw new DependencyHasNoDefaultValueException( "Class: {$parameter->name} dependency can not be resolved" );
}
} else {
$dependencies[] = $this->get( $dependency );
}
}
return $dependencies;
}
}