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Interface busrider.Strategy

public interface Strategy

Each Player in the game has an associated Strategy. The conductor calls this interface when:

• a game begins (startGame),
• the game ends (endGame),
• any player becomes fast (playerIsFast),
• any route is bought or sold (transferRoute),
• another player rides this player's routes, and thereby pays a fare (receiveFare).
• the player's turn begins (startTurn),
• the player's turn ends (endTurn),
• the player may select a destination (chooseDestination),
• the player arrives at his destination terminus (youArrived),
• the Strategy may select the player's Segment, a part of the routes along which the player travels (chooseSegment),
• the Strategy may choose a Route for the player to sell (youMustSell),
• the player goes bankrupt, and therefore leaves the game (youAreBroke),

Some of the methods return values. It is always legal to return null, after which the conductor will make a selection on behalf of the player. This may be a poor choice, but allows one to participate with minimal effort. (Indeed, this is what StrategyAdapter does.) Throwing an exception out of an interface method has the same effect.

Since route selection may be somewhat difficult for the programmer, the conductor tries to make good Segment choices. Other decisions of the conductor are likely to be abysmal, and are documented below.

See Also:

StrategyAdapter, Player

Method Index

beginTurn()

called at the start of the player's turn.

chooseDestination(Junction, Junction)

called to let the Strategy choose one of two Destinations.

chooseSegment(int)

called whenever it is the player's turn to move, and the Strategy may choose a Segment to follow.

endGame(int)

indicates that the game has ended.

endTurn()

called at the end of the player's turn.

playerIsFast(int)

called whenever a player buys a Right-of-way.

receiveFare(int, int)

called whenever someone pays this player for riding on his routes.

startGame(Game, PlayerView)

indicates that a game is starting.

transferRoute(int)

called whenever a route changes ownership, after the change.

youAreBroke()

called near the end of a player's turn, when his cash is negative, and the player has nothing to sell.

youArrived()

called to inform the player of his arrival at his destination.

youMustSell()

called near the end of a player's turn, when his cash is negative.

Methods

 public abstract void startGame(Game ga,
                                PlayerView me)

indicates that a game is starting. The Strategy can keep a reference to the Game parameter, or can fetch it by Game.getInstance(). One can can inspect the Game, to see the Board, the number of players, their locations, etc.

The PlayerView parameter is a view to the Strategy's player. This differs from the PlayerViews obtainable from the Game, in that one can always see one's own cash. We recommend that the Strategy keep that reference: it is the only way to see one's cash!

 public abstract void endGame(int winner)

indicates that the game has ended. winner is the player-index of the winner, or -1 if no player has won.

 public abstract void playerIsFast(int playerIndex)

called whenever a player buys a Right-of-way. playerIndex specifies which player bought.

 public abstract void transferRoute(int routeIndex)

called whenever a route changes ownership, after the change. routeIndex specifies which route. The Game can be queried to see the new owner.

 public abstract void receiveFare(int fromwhom,
                                  int payment)

called whenever someone pays this player for riding on his routes. The player's cash is already updated.

fromwhom is the rider's player-index.

 public abstract void beginTurn()

called at the start of the player's turn.

 public abstract void endTurn()

called at the end of the player's turn.

 public abstract Junction chooseDestination(Junction term1,
                                            Junction term2)

called to let the Strategy choose one of two Destinations.

The Strategy will return one of the two parameters. (Otherwise the first is selected.)

 public abstract Purchase youArrived()

called to inform the player of his arrival at his destination. The bank has already credited his cash.

The Strategy will return a Purchase reference, or null (meaning purchase nothing). If the purchase is legal, it is made; otherwise nothing is purchased.

 public abstract Segment chooseSegment(int roll)

called whenever it is the player's turn to move, and the Strategy may choose a Segment to follow. This routine is called even if there is only one choice.

roll indicates the remainder of the player's dice roll for this turn.

The Strategy may return null or an invalid Segment, in which case the conductor will make a legal choice (and probably a reasonable one).

 public abstract Route youMustSell()

called near the end of a player's turn, when his cash is negative. This routine is called even if the player has only one route to sell.

The Strategy will return the index of a route, indicating which route to sell. If it returns null, or tries to sell a route which the player does not own, the conductor will choose a route.

 public abstract void youAreBroke()

called near the end of a player's turn, when his cash is negative, and the player has nothing to sell. The player has therefore lost. The player will not have any more turns, and the Strategy will not be informed of other player's activities. It will receive its last endTurn call, and an endGame call.

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