question: public boolean validate ( String telephone ) { char aChar ; StringBuilder buf = new StringBuilder ( telephone ) ; for ( int aIndex = 0 ; aIndex < buf . length ( ) ; aIndex ++ ) { aChar = buf . charAt ( aIndex ) ; if ( ! Character . isSpaceChar ( aChar ) ) { if ( ! Character . isDigit ( aChar ) && ! isValidTelephoneChars ( aChar ) ) { return false ; } } } return true ; }
target:  Determines whether the specified string is a valid "basic" telephone number string