question: private void fillDeclaredPrefixes ( XMLStreamReader reader ) { fDeclaredPrefixes . clear ( ) ; final int len = reader . getNamespaceCount ( ) ; for ( int i = 0 ; i < len ; ++ i ) { String prefix = reader . getNamespacePrefix ( i ) ; fDeclaredPrefixes . add ( prefix != null ? prefix : "" ) ; } }
target:  Fills in the list of declared prefixes.