question: private boolean isUnsignedNumber ( String string ) { String s = string . trim ( ) ; if ( s . length ( ) < 1 ) return false ; if ( s . charAt ( 0 ) != '+' && s . charAt ( 0 ) != '-' ) { double value = 0 ; try { value = Double . parseDouble ( s ) ; } catch ( NumberFormatException e ) { return false ; } return true ; } return false ; }
target:  Tell whether the string contains an unsigned number.