question: private static String genClassID ( String fileExt , int regLevel ) { boolean isClsIDExist = true ; String appendix , temClsID , temClsIDKey , temFileExt ; temFileExt = fileExt . trim ( ) ; if ( temFileExt . charAt ( 0 ) == '.' ) { temFileExt = temFileExt . substring ( 1 ) ; } int i = 1 ; while ( ( isClsIDExist ) && ( i < MAX_CLSID_NUMBER ) ) { appendix = Integer . toString ( i ) ; temClsID = "class" + temFileExt + appendix ; if ( temClsID != null ) { temClsIDKey = getClsIDKey ( temClsID , regLevel ) ; if ( temClsIDKey != null ) { isClsIDExist = isSubKeyExist ( temClsIDKey , regLevel ) ; if ( ! isClsIDExist ) { return temClsID ; } } } i ++ ; } return null ; }
target:  Constructs a new class ID name based on the given fileExt name by adding a sequence number at the rear of the given fileExt.