ActionScript 3.0 Design Patterns.pdf - VideoTutorials-bg.com

were reviewed, we’d like to focus on a more general key OOP concept for the Symmetric
Proxy design pattern—flexibility.
Because the Symmetric Proxy design focuses on interaction over the Internet, we
need to look at two different kinds of flexibility. First, we need to look at communication
flexibility. That is, can the model be used with different communication technologies
over the Internet? Second, we must consider game flexibility. To what
extent can different games be employed with the design?
Communication Flexibility
The first question to address is whether or not any trans-Internet communication can
work with the Symmetric Proxy pattern. Because of its ease of use and built-in features
like remote shared objects, using an application such as Flash Media Server 2
has a built-in disadvantage as a communication testing and development platform
for a general communication design pattern. The server-side script automatically
informs all players of the current game state in the form of one or both players having
moved. Once both players have moved, the referee determines who has won and
resets the game for another round.
In the original model of the Symmetric Proxy and the Androgynous variation, as long
as the proxy player makes the same move as the original player, whether FMS,
another open socket technology, or middleware such as PHP, C#, Perl, ColdFusion,
or VB.NET, is not important. The move for the proxy is the only state that really
needs to be sent over the Internet. The proxy plays the move, and the referee takes
care of deciding whether the proxy or its player opponent wins, displaying the outcome
and resetting the variables for a new game. So any communication system that
can send the player’s state to its proxy is acceptable, meeting the criteria of communication
flexibility.
Game Flexibility
In the implementation you will see in this chapter, the referee’s not quite as active as
the one envisioned by Heliotis and Schreiner. The primary difference is that the referee
only inspects the moves after both moves have been made in a game. Because
each round in a game of RPS is a complete game, each game is over as soon as both
players have moved. At this point, the referee kicks in with its template method,
decides who won, displays the outcome, and resets the values to the start states.
One way of reducing the referee’s work is in the UI. Players can only enter one of
three different moves displayed on the buttons. The real player blocks any attempt to
make any other move, such as one where the player has not made a move selection.
In a more complexgame with a wider selection of moves, either more responsibilities
would be delegated to the referee or the UI would take care of allowing a wider
but still limited move set.
476 | Chapter 13: Symmetric Proxy Pattern