// This example is from _Java Examples in a Nutshell_. (http://www.oreilly.com)
// Copyright (c) 1997 by David Flanagan
// This example is provided WITHOUT ANY WARRANTY either expressed or implied.
// You may study, use, modify, and distribute it for non-commercial purposes.
// For any commercial use, see http://www.davidflanagan.com/javaexamples
import java.rmi.*;
import java.util.Vector;
import java.io.IOException;
/**
* This class defines three nested Remote interfaces for use by our MUD game.
* It also defines a bunch of exception subclasses, and a constant string
* prefix used to create unique names when registering MUD servers
**/
public class Mud {
/**
* This interface defines the exported methods of the MUD server object
**/
public interface RemoteMudServer extends Remote {
/** Return the name of this MUD */
public String getMudName() throws RemoteException;
/** Return the main entrance place for this MUD */
public RemoteMudPlace getEntrance() throws RemoteException;
/** Look up and return some other named place in this MUD */
public RemoteMudPlace getNamedPlace(String name)
throws RemoteException, NoSuchPlace;
/**
* Dump the state of the server to a file so that it can be restored later
* All places, and their exits and things are dumped, but the "people"
* in them are not.
**/
public void dump(String password, String filename)
throws RemoteException, BadPassword, IOException;
}
/**
* This interface defines the methods exported by a "person" object that
* is in the MUD.
**/
public interface RemoteMudPerson extends Remote {
/** Return a full description of the person */
public String getDescription() throws RemoteException;
/** Deliver a message to the person */
public void tell(String message) throws RemoteException;
}
/**
* This is the most important remote interface for the MUD. It defines the
* methods exported by the "places" or "rooms" within a MUD. Each place
* has a name and a description, and also maintains a list of "people" in
* the place, things in the place, and exits from the place. There are
* methods to get a list of names for these people, things, and exits. There
* are methods to get the RemoteMudPerson object for a named person, to get
* a description of a named thing, and to go through a named exit.
* There are methods for interacting with other people in the MUD.
* There are methods for building the MUD by creating and destroying
* things, adding new places (and new exits to those places), for linking
* a place through a new exit to some other place (possibly on another
* MUD server), and for closing down an existing exit.
**/
public interface RemoteMudPlace extends Remote {
/** Look up the name of this place */
public String getPlaceName() throws RemoteException;
/** Get a description of this place */
public String getDescription() throws RemoteException;
/** Find out the names of all people here */
public Vector getNames() throws RemoteException;
/** Get the names of all things here */
public Vector getThings() throws RemoteException;
/** Get the names of all ways out of here */
public Vector getExits() throws RemoteException;
/** Get the RemoteMudPerson object for the named person. */
public RemoteMudPerson getPerson(String name)
throws RemoteException, NoSuchPerson;
/** Get more details about a named thing */
public String examineThing(String name) throws RemoteException,NoSuchThing;
/** Use the named exit */
public RemoteMudPlace go(RemoteMudPerson who, String direction)
throws RemoteException,NotThere,AlreadyThere,NoSuchExit,LinkFailed;
/** Send a message of the form "David: hi everyone" */
public void speak(RemoteMudPerson speaker, String msg)
throws RemoteException, NotThere;
/** Send a message of the form "David laughs loudly" */
public void act(RemoteMudPerson speaker, String msg)
throws RemoteException, NotThere;
/** Add a new thing in this place */
public void createThing(RemoteMudPerson who, String name,
String description)
throws RemoteException, NotThere, AlreadyThere;
/** Remove a thing from this place */
public void destroyThing(RemoteMudPerson who, String thing)
throws RemoteException, NotThere, NoSuchThing;
/** Create a new place, bi-directionally linked to this one by an exit */
public void createPlace(RemoteMudPerson creator,
String exit, String entrance,
String name, String description)
throws RemoteException,NotThere,ExitAlreadyExists,PlaceAlreadyExists;
/**
* Link this place (unidirectionally) to some existing place. The
* destination place may even be on another server.
**/
public void linkTo(RemoteMudPerson who, String exit,
String hostname, String mudname, String placename)
throws RemoteException, NotThere, ExitAlreadyExists, NoSuchPlace;
/** Remove an existing exit */
public void close(RemoteMudPerson who, String exit)
throws RemoteException, NotThere, NoSuchExit;
/**
* Remove this person from this place, leaving them nowhere.
* Send the specified message to everyone left in the place.
**/
public void exit(RemoteMudPerson who, String message)
throws RemoteException, NotThere;
/**
* Put a person in a place, assigning their name, and sending the
* specified message to everyone else in the place. The client should
* not make this method available to the user. They should use go()
* instead.
**/
public void enter(RemoteMudPerson who, String name, String message)
throws RemoteException, AlreadyThere;
/**
* Return the server object of the MUD that "contains" this place
* This method should not be directly visible to the player
**/
public RemoteMudServer getServer() throws RemoteException;
}
/**
* This is a generic exception class that serves as the superclass
* for a bunch of more specific exception types
**/
public static class MudException extends Exception {}
/**
* These specific exception classes are thrown in various contexts.
* The exception class name contains all the information about the exception;
* no detail messages are provided by these classes.
**/
public static class NotThere extends MudException {}
public static class AlreadyThere extends MudException {}
public static class NoSuchThing extends MudException {}
public static class NoSuchPerson extends MudException {}
public static class NoSuchExit extends MudException {}
public static class NoSuchPlace extends MudException {}
public static class ExitAlreadyExists extends MudException {}
public static class PlaceAlreadyExists extends MudException {}
public static class LinkFailed extends MudException {}
public static class BadPassword extends MudException {}
/**
* This constant is used as a prefix to the MUD name when the server
* registers the mud with the RMI Registry, and when the client looks
* up the MUD in the registry. Using this prefix helps prevent the
* possibility of name collisions.
**/
static final String mudPrefix = "com.davidflanagan.mud.";
}
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