Design
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Design

There are two classes to design: the InvalidBet exception and the Table class.

InvalidBet Exception

InvalidBet is thrown when the Player attempts to place a bet which exceeds the table's limit.

 InvalidBet extends Exception {
}

This class simply inherits all features of the superclass.

In Python, the declaration must have a body, and the pass statement is used for this purpose.

class  InvalidBet ( Exception ): 
    pass 

Table Class

Table contains all the Bets created by the Player. A table also has a betting limit, and the sum of all of a player's bets must be less than or equal to this limit. We assume a single Player in the simulation.

Fields

  • int limit ;

    This is the table limit. The sum of a Player's bets must be less than or equal to this limit.

  • List bets ;

    This is a LinkedList of the Bets currently active. These will result in either wins or losses to the Player.

Constructors

  • Table();

    Creates an empty LinkedList of bets.

Methods

  • boolean isValid(Bet bet);

    Validates this bet. If the sum of all bets is less than or equal to the table limit, then the bet is valid, return true. Otherwise, return false.

  • void placeBet(Bet bet)
        throws InvalidBet;

    Adds this bet to the list of working bets. If the sum of all bets is greater than the table limit, then an exception should be thrown (Java) or raised (Python). This is a rare circumstance, and indicates a bug in the Player more than anything else.

  • ListIterator iterator();

    Returns a ListIterator over the list of bets. This gives us the freedom to change the representation from LinkedList to any other Collection with no impact to other parts of the application.

    In Python, we can return an iterator over the available list of Bet instances. The traditional Python approach is to return the list object itself, rather than an iterator over the list. With the introduction of the generators in Python 2.3, however, it can be slightly more flexible to return an iterator rather than the list object.

    Note that we need to be able remove Bets from the table. Consequently, we have to update the list, which requires that we use a ListIterator, not an Iterator.

  • Java: public String toString();

    Python: def __str__(self):

    reports on all of the currently placed bets.

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