/// <summary>
/// Takes a <see cref="Common.Person">Person</see> and allows them
/// to join the chat room, if there is not already a chatter with
/// the same name
/// </summary>
/// <param name="person"><see cref="Common.Person">Person</see> joining</param>
/// <returns>An array of <see cref="Common.Person">Person</see> objects</returns>
public Person[] Join(Person person)
{
bool userAdded = false;
//create a new ChatEventHandler delegate, pointing to the MyEventHandler() method
myEventHandler = new ChatEventHandler(MyEventHandler);
//carry out a critical section that checks to see if the new chatter
//name is already in use, if its not allow the new chatter to be
//added to the list of chatters, using the person as the key, and the
//ChatEventHandler delegate as the value, for later invocation
lock (syncObj)
{
if (!checkIfPersonExists(person.Name) && person != null)
{
this.person = person;
chatters.Add(person, MyEventHandler);
userAdded = true;
}
}
//if the new chatter could be successfully added, get a callback instance
//create a new message, and broadcast it to all other chatters, and then
//return the list of al chatters such that connected clients may show a
//list of all the chatters
if (userAdded)
{
callback = OperationContext.Current.GetCallbackChannel <IChatCallback>();
ChatEventArgs e = new ChatEventArgs();
e.msgType = MessageType.UserEnter;
e.person = this.person;
BroadcastMessage(e);
//add this newly joined chatters ChatEventHandler delegate, to the global
//multicast delegate for invocation
ChatEvent += myEventHandler;
Person[] list = new Person[chatters.Count];
//carry out a critical section that copy all chatters to a new list
lock (syncObj)
{
chatters.Keys.CopyTo(list, 0);
}
return(list);
}
else
{
return(null);
}
}
/// <summary>
///loop through all connected chatters and invoke their
///ChatEventHandler delegate asynchronously, which will firstly call
///the MyEventHandler() method and will allow a asynch callback to call
///the EndAsync() method on completion of the initial call
/// </summary>
/// <param name="e">The ChatEventArgs to use to send to all connected chatters</param>
private void BroadcastMessage(ChatEventArgs e)
{
ChatEventHandler temp = ChatEvent;
//loop through all connected chatters and invoke their
//ChatEventHandler delegate asynchronously, which will firstly call
//the MyEventHandler() method and will allow a asynch callback to call
//the EndAsync() method on completion of the initial call
if (temp != null)
{
foreach (ChatEventHandler handler in temp.GetInvocationList())
{
handler.BeginInvoke(this, e, new AsyncCallback(EndAsync), null);
}
}
}
/// <summary>
///loop through all connected chatters and invoke their
///ChatEventHandler delegate asynchronously, which will firstly call
///the MyEventHandler() method and will allow a asynch callback to call
///the EndAsync() method on completion of the initial call
/// </summary>
/// <param name="e">The ChatEventArgs to use to send to all connected chatters</param>
private void BroadcastMessage(ChatEventArgs e)
{
ChatEventHandler temp = ChatEvent;
//loop through all connected chatters and invoke their
//ChatEventHandler delegate asynchronously, which will firstly call
//the MyEventHandler() method and will allow a asynch callback to call
//the EndAsync() method on completion of the initial call
if (temp != null)
{
foreach (ChatEventHandler handler in temp.GetInvocationList())
{
handler.BeginInvoke(this, e, new AsyncCallback(EndAsync), null);
}
}
}
/// <summary>
/// This method is called when ever one of the chatters
/// ChatEventHandler delegates is invoked. When this method
/// is called it will examine the events ChatEventArgs to see
/// what type of message is being broadcast, and will then
/// call the correspoding method on the clients callback interface
/// </summary>
/// <param name="sender">the sender, which is not used</param>
/// <param name="e">The ChatEventArgs</param>
private void MyEventHandler(object sender, ChatEventArgs e)
{
try
{
switch (e.msgType)
{
case MessageType.Receive:
callback.Receive(e.person, e.message);
break;
case MessageType.ReceiveWhisper:
callback.ReceiveWhisper(e.person, e.message);
break;
case MessageType.UserEnter:
callback.UserEnter(e.person);
break;
case MessageType.UserLeave:
callback.UserLeave(e.person);
break;
}
}
catch
{
Leave();
}
}
/// <summary>
/// A request has been made by a client to leave the chat room,
/// so remove the <see cref="Common.Person">Person </see>from
/// the internal list of chatters, and unwire the chatters
/// delegate from the multicast delegate, so that it no longer
/// gets invokes by globally broadcasted methods
/// </summary>
public void Leave()
{
if (this.person == null)
return;
//get the chatters ChatEventHandler delegate
ChatEventHandler chatterToRemove = getPersonHandler(this.person.Name);
//carry out a critical section, that removes the chatter from the
//internal list of chatters
lock (syncObj)
{
chatters.Remove(this.person);
}
//unwire the chatters delegate from the multicast delegate, so that
//it no longer gets invokes by globally broadcasted methods
ChatEvent -= chatterToRemove;
ChatEventArgs e = new ChatEventArgs();
e.msgType = MessageType.UserLeave;
e.person = this.person;
this.person = null;
//broadcast this leave message to all other remaining connected
//chatters
BroadcastMessage(e);
}
/// <summary>
/// Broadcasts the input msg parameter to all the <see cref="Common.Person">
/// Person</see> whos name matches the to input parameter
/// by looking up the person from the internal list of chatters
/// and invoking their ChatEventHandler delegate asynchronously.
/// Where the MyEventHandler() method is called at the start of the
/// asynch call, and the EndAsync() method at the end of the asynch call
/// </summary>
/// <param name="to">The persons name to send the message to</param>
/// <param name="msg">The message to broadcast to all chatters</param>
public void Whisper(string to, string msg)
{
ChatEventArgs e = new ChatEventArgs();
e.msgType = MessageType.ReceiveWhisper;
e.person = this.person;
e.message = msg;
try
{
ChatEventHandler chatterTo;
//carry out a critical section, that attempts to find the
//correct Person in the list of chatters.
//if a person match is found, the matched chatters
//ChatEventHandler delegate is invoked asynchronously
lock (syncObj)
{
chatterTo = getPersonHandler(to);
if (chatterTo == null)
{
throw new KeyNotFoundException("The person whos name is " + to +
" could not be found");
}
}
//do a async invoke on the chatter (call the MyEventHandler() method, and the
//EndAsync() method at the end of the asynch call
chatterTo.BeginInvoke(this, e, new AsyncCallback(EndAsync), null);
}
catch (KeyNotFoundException)
{
}
}
/// <summary>
/// Broadcasts the input msg parameter to all connected chatters
/// by using the BroadcastMessage() method
/// </summary>
/// <param name="msg">The message to broadcast to all chatters</param>
public void Say(string msg)
{
ChatEventArgs e = new ChatEventArgs();
e.msgType = MessageType.Receive;
e.person = this.person;
e.message = msg;
BroadcastMessage(e);
}
/// <summary>
/// Takes a <see cref="Common.Person">Person</see> and allows them
/// to join the chat room, if there is not already a chatter with
/// the same name
/// </summary>
/// <param name="person"><see cref="Common.Person">Person</see> joining</param>
/// <returns>An array of <see cref="Common.Person">Person</see> objects</returns>
public Person[] Join(Person person)
{
bool userAdded = false;
//create a new ChatEventHandler delegate, pointing to the MyEventHandler() method
myEventHandler = new ChatEventHandler(MyEventHandler);
//carry out a critical section that checks to see if the new chatter
//name is already in use, if its not allow the new chatter to be
//added to the list of chatters, using the person as the key, and the
//ChatEventHandler delegate as the value, for later invocation
lock (syncObj)
{
if (!checkIfPersonExists(person.Name) && person != null)
{
this.person = person;
chatters.Add(person, MyEventHandler);
userAdded = true;
}
}
//if the new chatter could be successfully added, get a callback instance
//create a new message, and broadcast it to all other chatters, and then
//return the list of al chatters such that connected clients may show a
//list of all the chatters
if (userAdded)
{
callback = OperationContext.Current.GetCallbackChannel<IChatCallback>();
ChatEventArgs e = new ChatEventArgs();
e.msgType = MessageType.UserEnter;
e.person = this.person;
BroadcastMessage(e);
//add this newly joined chatters ChatEventHandler delegate, to the global
//multicast delegate for invocation
ChatEvent += myEventHandler;
Person[] list = new Person[chatters.Count];
//carry out a critical section that copy all chatters to a new list
lock (syncObj)
{
chatters.Keys.CopyTo(list, 0);
}
return list;
}
else
{
return null;
}
}
