AliasCollection.php
public function getId($alias)
    {
        if (!isset($this->aliases[$alias])) {
            return null;
        }

        $id = $this->aliases[$alias];
        while (isset($this->aliases[$id])) {
            $id = $this->aliases[$id];
        }

        return $id;
    }
public function getId($alias)
    {
        if (!isset($this->aliases[$alias])) {
            return null;
        }

        $id = $this->aliases[$alias];
        while (isset($this->aliases[$id])) {
            $id = $this->aliases[$id];
        }

        return $id;
    }
public function getId ( $ alias ) { if ( ! isset ( $ this -> aliases [ $ alias ] ) ) { return null ; } $ id = $ this -> aliases [ $ alias ] ; while ( isset ( $ this -> aliases [ $ id ] ) ) { $ id = $ this -> aliases [ $ id ] ; } return $ id ; }
Returns the identifier of the item which has the given alias

@param string $alias The item alias

@return string|null The item identifier or null if no one item has the given alias
Returns the identifier of the item which has the given alias