/**
* Adds an existing channel to the folder. If the given channel is already
* part of another folder, it will be automatically removed from the old folder.
*
* @param MessageChannel $channel The channel which should be added to the folder.
*
* @return AbstractPostboxFolder Returns itself (fluent-interface)
*/
public function addChannel(MessageChannel $channel)
{
// first remove the channel
/* @var $oldFolder AbstractPostboxFolder */
$oldFolder = $channel->loadRelatedObject('PostboxFolder2MessageChannel');
if ($oldFolder !== null) {
$oldFolder->removeChannel($channel);
}
$this->createAssociation('PostboxFolder2MessageChannel', $channel);
return $this;
}