Conditionally update the list cell

Question

Is it possible to update the list cell based on a given condition?
I was trying something like this, but it turns out that updateItem() is called later (and not when the Listview is updated from the ObservableList which i presumed)
public class lCell extends ListCell<String> {
@Override
public void updateItem(String item, boolean empty) {
            super.updateItem(item, empty);
            label.setText(getItem());//hbox contains image & a label
            System.out.println(item);
            if (item != null && !isCurrentUser)
              setGraphic(hbox);// Set the list cell as a hbox
            else if (item!=null && isCurrentUser)
             setText(getItem()); //Set it as the message present in the ObservableList
        }isCurrentUser is a "global" variable which changes it's value in a method (when another user - other than the one currently posting messages -enters the message)
Is there a way to get an output like:
<Image> User 1:
msg1
msg2
msg3...
<Image> User2:
msg1
msg2...
<Image> User1:
msgs...

Answer 1

Like you said, I created an object userMessage which has the username and the message. >>
public class userMessage {
        private static String user;
        private static String message;
        public userMessage(String u, String m) {
        this.user = u;
        this.message=m;
        public static String getUser() {
        return user;
        public void setUser(String user) {
        this.user = user;
        public static String getMessage() {
        return message;
        public void setMessage(String message) {
        this.message = message;
}And my list cell class looks something like this:
public class lCell extends ListCell<userMessage> {
@Override
        public void updateItem(userMessage item, boolean empty) {
            super.updateItem(item, empty);
            if (item != null)
                StringBuilder sb = new StringBuilder();
                sb.append(item.getUser()).append(": \n").append(item.getMessage());
                setText(sb.toString());
}Q). How do I add a <user name> and a <message> to the list?
I thought, if i want a new message to be sent, i call a function add() which does the needful.>>
public void add(String user, String message)
       userMessage um = new userMessage(user, message);
       obs.addAll(um);
}But it seems like the last known item (object) created over rides all the previous ones.
so if for example I have:
add(user1, Hi);
add(user2, Hi!);
add(user1, zzz); The list view shows me:
user1, zzz
user1, zzz
user1, zzz
What do I do to prevent this? Do I have to create a different object every time? :\