Signalling between two Windows

Question

I am not sure how to signal between two Windows created in the same Thread.
Suppose I have two Windows, WindowA and WindowB (either is a descendent from the Window hierarchy - ie. JFrame, JDialog, etc.).
WindowB can be instantiated with different parameters that cause it to look different.
I want to do something like this in a method in my WindowA class: (pseudo-code)
for int 1 to n
hide this window; (i.e. WindowA)
instantiate and display a new WindowB object (with xxxxx parameters)
wait for WindowB to signal this WindowA object that it should
now create a new WindowB object and display that new object
somewhere in Class code for WindowB
signal WindowA;
How do I set up a "wait and signal" between the two Windows? Without it, WindowA will keep going through the for loop creating new Windows immediately -> I would like it to wait until WindowB signals that it is ok to do so.
Thanks for any help.
-TJW

Answer 1

Here's an example:
class CreateWindows {
     int count = 0;
     int limit = 5;
     public CreateWindows(int limit) {
          this.limit = limit;
          create();
     void create() {
          if (++count < limit) {
               new WindowA(new SignalListener() {
                    public void signal() {
                         create();
interface SignalListener {
     void signal();
class WindowA {
     public WindowA(SignalListener listener) {
          // do things
          listener.signal();