question: public static int findWordStart ( String line , int pos , String noWordSep ) { char ch = line . charAt ( pos - 1 ) ; if ( noWordSep == null ) { noWordSep = "" ; } boolean selectNoLetter = ( ! Character . isLetterOrDigit ( ch ) && noWordSep . indexOf ( ch ) == - 1 ) ; int wordStart = 0 ; for ( int i = pos - 1 ; i >= 0 ; i -- ) { ch = line . charAt ( i ) ; if ( selectNoLetter ^ ( ! Character . isLetterOrDigit ( ch ) && noWordSep . indexOf ( ch ) == - 1 ) ) { wordStart = i + 1 ; break ; } } return wordStart ; }
target:  Locates the start of the word at the specified position.