How to avoid using this in a constructor
- by Paralife
I have this situation:
interface MessageListener
{
void onMessageReceipt(Message message);
}
class MessageReceiver
{
MessageListener listener;
public MessageReceiver(MessageListener listener, other arguments...)
{
this.listener = listener;
}
loop()
{
Message message = nextMessage();
listener.onMessageReceipt(message);
}
}
and I want to avoid the following pattern: (Using the this in the Client constructor)
class Client implements MessageListener
{
MessageReceiver receiver;
MessageSender sender;
public Client(...)
{
receiver = new MessageReceiver(this, other arguments...);
sender = new Sender(...);
}
.
.
.
@Override
public void onMessageReceipt(Message message)
{
if(Message.isGood())
sender.send("Congrtulations");
else
sender.send("Boooooooo");
}
}
The reason why i need the above functionality is because i want to call the sender inside the onMessageReceipt() function, for example to send a reply. But I dont want to pass the sender into a listener, so the only way I can think of is containing the sender in a class that implements the listener, hence the above resulting Client implementation. Is there a way to achive this without the use of 'this' in the constructor? It feels bizare and i dont like it, since i am passing myself to an object(MessageReceiver) before I am fully constructed. On the other hand, the MessageReceiver is not passed from outside, it is constructed inside, but does this 'purifies' the bizarre pattern?
I am seeking for an alternative or an assurance of some kind that this is safe, or situations on which it might backfire on me.
