FOF30\Model\DataModel::checkIn PHP Method

    public function checkIn($userId = null)
    {
        // If there is no loaded record we can't do much, I'm afraid
        if (!$this->getId()) {
            throw new RecordNotLoaded("Can't checkin a not loaded DataModel");
        }
        // If the lock fields are missing we have nothing to do
        if (!$this->hasField('locked_by') && !$this->hasField('locked_on')) {
            return $this;
        }
        // If there's no locked_by field we just unlock and return
        if (!$this->hasField('locked_by')) {
            return $this->unlock();
        }
        // If the current user and the user who locked the record are the same, unlock it.
        if (empty($userId)) {
            $userId = $this->container->platform->getUser()->id;
        }
        $lockedBy = $this->getFieldValue('locked_by');
        if (empty($lockedBy) || $lockedBy == $userId) {
            return $this->unlock();
        }
        // Get the component privileges
        $platform = $this->container->platform;
        $component = $this->container->componentName;
        $privileges = array('editown' => $platform->authorise('core.edit.own', $component), 'editstate' => $platform->authorise('core.edit.state', $component), 'admin' => $platform->authorise('core.admin', $component), 'manage' => $platform->authorise('core.manage', $component));
        // If we are trackign assets get the item's privileges
        if ($this->isAssetsTracked()) {
            $assetKey = $this->getAssetKey();
            $assetPrivileges = array('editown' => $platform->authorise('core.edit.own', $assetKey), 'editstate' => $platform->authorise('core.edit.state', $assetKey));
            foreach ($assetPrivileges as $k => $v) {
                $privileges[$k] = $privileges[$k] || $v;
            }
        }
        // If you are a Super User, component manager or allowed to edit the state of records we unlock it
        if ($privileges['admin'] || $privileges['manage'] || $privileges['editstate']) {
            return $this->unlock();
        }
        // If you are the owner of the record and have core.edit.own privilege we will unlock it.
        $owner = 0;
        if ($this->hasField('created_by')) {
            $owner = $this->getFieldValue('created_by');
        }
        if ($privileges['editown'] && $owner == $userId) {
            return $this->unlock();
        }
        // All else failed, you don't have the privilege to unlock this item.
        throw new LockedRecord();
    }