private function setIndexes($indexes)
{
if (is_string($indexes)) {
$indexes = array_map("trim", explode(" ", $indexes));
} elseif (!is_array($indexes)) {
throw new \DomainException(sprintf("Array or string required for root index names: %s provided", gettype($indexes)));
} else {
foreach ($indexes as $index) {
if (!is_string($index)) {
throw new \DomainException(sprintf("Array of string index filenames required: %s provided", gettype($index)));
}
}
}
$this->indexes = array_filter($indexes);
}