private boolean isIdentifier(String token){
  int size=token.length();
  for (int i=0; i < size; i++) {
    char c=token.charAt(i);
    if (isOperator(c))     return false;
  }
  if (token.startsWith("'") && token.endsWith("'"))   return false;
 else {
    try {
      new BigDecimal(token);
      return false;
    }
 catch (    NumberFormatException e) {
    }
  }
  if (isSQLFunctions(token))   return false;
  return true;
}

private boolean isIdentifier ( String token ) { int size = token . length ( ) ; for ( int i = 0 ; i < size ; i ++ ) { char c = token . charAt ( i ) ; if ( isOperator ( c ) ) return false ; } if ( token . startsWith ( "'" ) && token . endsWith ( "'" ) ) return false ; else { try { new BigDecimal ( token ) ; return false ; } catch ( NumberFormatException e ) { } } if ( isSQLFunctions ( token ) ) return false ; return true ; }
check if token is a valid sql identifier
