How to create a listener to a method in java

Question

I\'m having a really bad time to implement a listener to a method.

In my current work i have to request a method every 5 seconds in order to verify for new information

Answer 1

Ok i manage to solve my problem.

I implemented a listener based on observer model. For that i had to implement a interface that i called XMPPmessageListener:

public interface XMPPmessageListener {
    public void readMsg(String senderJID, String msg); 
}

than in the XmppHandler class, the class of the methods processMessage and getMessage i added methods to add and remove listeners and a LinkedList to store the listeners:

private LinkedList<XMPPmessageListener> listeners = new LinkedList<XMPPmessageListener>();

public void addMsgListener(XMPPmessageListener listener){
    listeners.add(listener);
}

public boolean removeMsgListener(XMPPmessageListener listener){
    return listeners.remove(listener);
}       

than i did some exchanges in processMessage method in order to warn the listeners:

public void processMessage(Chat chat, Message message) {
    if (message.getType() == Message.Type.chat) {
        for(XMPPmessageListener l: listeners){
            l.readMsg(chat.getParticipant().toString(), message.getBody().toString());
        }
    }
} 

Now i can be notified at any method everytime a message is receive by creating a XMPPmessageListener and decide what to do with the message by overriding the readMsg method:

XmppHandler xmpp = new XmppHandler(XMPPuser, XMPPpassword, XMPPaddress, XMPPdomain, XMPPport);

XMPPmessageListener msglistener = new XMPPmessageListener() {

                @Override
                public void readMsg(String senderJID, String msg) {
                    String asw=xmlHandler.processMsg(msg,senderJID);

                }
            };
            xmpp.addMsgListener(msglistener);