/**
* Gets the parent collection names for each route collection.
*
* @return array An array where the key is the collection name and the
* value is an array of the parent collection names.
*/
protected function _getCollectionHierarchy()
{
$parents = array();
foreach ($this as $collectionName => $collection) {
$parents[$collectionName] = $collection->getParent();
}
$tree = Iterable::toTree($parents);
$keys = Iterable::arrayKeysMultidimensional($tree);
$result = array();
foreach ($keys as $key) {
$result[$key] = array_merge((array) Iterable::getParentsFromKey($key, $tree), array($key));
}
return $result;
}
