package connex.core.Presence;

import java.util.Vector;
import net.jxta.endpoint.Message;


class MessageQueue extends Thread {
    private Vector messages = new Vector();

    /**
     * @directed 
     */
    private MessageProcessor mprocessor;
    private boolean start = true;


    protected MessageQueue(MessageProcessor mprocessor) {
        this.mprocessor = mprocessor;
    }

    protected void stopIt() {
        start = false;
    }

    public void run() {
        Message message = null;
        while (start) {
            try {
                message = pop();

            } catch (InterruptedException e) {

                break;
            }

            if (message != null) {
                mprocessor.process(message);
            }
        }
    }

    public synchronized void push(Message message) {
        boolean shouldNotify = (messages.size() == 0);

        // add the message to the end of the vector
        messages.addElement(message);

        if (shouldNotify) {
            // notify the thread

            notify();
        }
    }

    private synchronized Message pop() throws InterruptedException {
        Message message = null;

        if (messages.size() == 0) {
            // wait for an element
            wait();
        }

        // pop the first element off of the vector
        if (messages.size() > 0) {
            message = (Message) messages.firstElement();
            messages.removeElementAt(0);
        }

        return message;
    }


}