bundles/org.eclipse.packagedrone.storage.apm/src/org/eclipse/packagedrone/storage/apm/StorageManager.java
private static State getSameParent ( final State parent, final MetaKey key )
    {
        State current = parent;
        while ( current != null )
        {
            if ( current.key.equals ( key ) )
            {
                return current;
            }

            current = current.parent;
        }
        return null;
    }
private static State getSameParent ( final State parent, final MetaKey key )
    {
        State current = parent;
        while ( current != null )
        {
            if ( current.key.equals ( key ) )
            {
                return current;
            }

            current = current.parent;
        }
        return null;
    }
Traverse up from the provided parent and find the first which uses the
same key

@param parent
the first parent candidate
@param key
the key to look for
@return the first parent (which may be the input parameter), which uses
the same key