question: public HeadRule ( String dir , String rule ) { String [ ] tmp = P_TAGSETS . split ( rule ) ; int i , size = tmp . length ; b_r2l = dir . equals ( DIR_RIGHT_TO_LEFT ) ; a_tagSets = new HeadTagSet [ size ] ; for ( i = 0 ; i < size ; i ++ ) a_tagSets [ i ] = new HeadTagSet ( tmp [ i ] ) ; }
target:  Constructs a new headrule by decoding the specific head tagsets.