wyvern.lib.commands
Class OfferCommand

java.lang.Object
  wyvern.lib.commands.OfferCommand

All Implemented Interfaces:

BuiltInCommand, Command

public class OfferCommand

extends java.lang.Object

implements BuiltInCommand

Implements a safe-trading system. A player can "offer" an item for sale in their inventory, optionally specifying a particular player to sell it to.

Version:

1.0, Apr 26, 2003

Author:

Steve Yegge

Field Summary

static int

AUCTION_FEE

Method Summary

void	addCommands(java.util.Map commands, CommandList list) Adds commands.
CommandEvent	createBuyEvent(CommandEvent event) Creates an event for buying an item from a player.
CommandEvent	createEvent(CommandEvent event) Implements Command.createEvent()
CommandEvent	createRescindEvent(CommandEvent event) Creates an event for rescinding an offer.
boolean	execute(CommandEvent ev) Executes the event by marking the item for sale.
boolean	executeBuyEvent(CommandEvent ev) Executes a purchase.
boolean	executeRescindEvent(CommandEvent ev) Executes a rescind.
static OfferCommand	getImpl()
CommandEvent	getTarget(CommandEvent event) Looks for the thing to offer for sale.
boolean	knowsCommand(java.lang.String command) Built-in commands always return true, so that *someone* handles it.
static void	main(java.lang.String[] args) Tests the regular expression for matching args.
CommandEvent	parseArgs(CommandEvent event) Splits up the args to the event.
static void	removeOfferingProperties(GameObject obj) Removes the properties set by the "offer" command, including the suffix showing the price.
CommandEvent	usage(CommandEvent event) Vetoes the event with a Usage message.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

AUCTION_FEE

public static final int AUCTION_FEE

See Also:

Constant Field Values

Method Detail

getImpl

public static OfferCommand getImpl()

addCommands

public void addCommands(java.util.Map commands,
                        CommandList list)

Adds commands.

Specified by:

addCommands in interface BuiltInCommand

Parameters:

commands - the map to add to

list - the command list we're registering in, from which we can derive the command agent (i.e. player or monster) and other information.

knowsCommand

public boolean knowsCommand(java.lang.String command)

Built-in commands always return true, so that *someone* handles it.

Specified by:

knowsCommand in interface Command

Parameters:

command - the complete original text of the command.

Returns:

true if we want to handle the command.

createEvent

public CommandEvent createEvent(CommandEvent event)

Implements Command.createEvent()

Specified by:

createEvent in interface Command

Parameters:

event - the initial, raw event

Returns:

a new event containing everything a Hook callback would need in order to modify or veto the event.

parseArgs

public CommandEvent parseArgs(CommandEvent event)

Splits up the args to the event.

Parameters:

event - the initial event

Returns:

the event, with up to 3 new properties set: - "target-obj": the description of the object - "price": the offering price - "buyer": the single player to offer it to (optional) Vetoes the event if it doesn't have well-formed arguments.

usage

public CommandEvent usage(CommandEvent event)

Vetoes the event with a Usage message.

getTarget

public CommandEvent getTarget(CommandEvent event)

Looks for the thing to offer for sale.

Parameters:

event - the original event, with args parsed into "item", "price", and optional "buyer" properties.

Returns:

If we found the target, returns a new TargetedEvent wrapping the target, containing the "price" and optional "buyer" properties. If not, returns the original event, vetoed with an appropriate failure message.

execute

public boolean execute(CommandEvent ev)

Executes the event by marking the item for sale.

Specified by:

execute in interface Command

Parameters:

ev - the CommandEvent to execute

Returns:

true if the event completed successfully, else false.

createRescindEvent

public CommandEvent createRescindEvent(CommandEvent event)

Creates an event for rescinding an offer.

executeRescindEvent

public boolean executeRescindEvent(CommandEvent ev)

Executes a rescind.

removeOfferingProperties

public static void removeOfferingProperties(GameObject obj)

Removes the properties set by the "offer" command, including the suffix showing the price. Called when rescinding an offer, and when someone buys the item successfully.

Parameters:

obj - an offered object for which to remove the properties

Returns:

the object, with "offer-price", "offered-by", etc. removed. The object is invalidated.

createBuyEvent

public CommandEvent createBuyEvent(CommandEvent event)

Creates an event for buying an item from a player.

Parameters:

event - the original event encapsulating the command

Returns:

an event containing "seller" and "item" properties, or else an event vetoed with an appropriate message.

executeBuyEvent

public boolean executeBuyEvent(CommandEvent ev)

Executes a purchase.

Parameters:

ev - a TargetedEvent created by createBuyEvent()

Returns:

true if successful

main

public static void main(java.lang.String[] args)

Tests the regular expression for matching args.