[_A-Za-z0-9]+Any string that does not satisfy this regular expression should be considered invalid and will cause an
<InvalidCommand> message to be printed. Please
note that all strings are CASE INSENSITIVE. That is to say that when a parameter
is said to be a string type, it is case insensitive. Strings should be sorted in
asciibetical order. (HINT: The String.compareTo() method does this by default!)