Mqtt multithreaded Java app

Question

I have a Java app which acts like a command server for other devices and communicated with them via MQTT. I want to add a new functionality and don't let my sender class (implemented as a thread) send another message if the receiver class (also implemented as a thread) doesn't allow him to, let's say when a message containing "ACK" is received from a device.

I am trying to achieve it with wait and notify but no luck until now. How should I implement it?

I tried initializing the sender class inside the receiver so I can manipulate the thread but it keeps losing the connection when I notify the sender so he becomes running again.

I can upload the code if needed, thank you in advance.

• Robert Harvey: I suggest you delete your question from this site and repost it to Stack Overflow, including the corresponding code. Implementation/coding help questions are off-topic here.
• George Sp: @RobertHarvey Isn't software engineering about software architecture too?
• Neil: @GeorgeSp You're asking for a way to make one thread wait for another, correct? This is not really a question of software architecture and more about relaying tasks between threads. I would recommend you read up on LinkedBlockingQueue. When one thread is ready, it calls take() and when the other is ready, it calls put() allowing your threads to collaborate.

Answer 1

I found a solution to my problem.

I moved my class definitions to the file that main exists and declared a volatile variable which works like a mutex and synchronizes the two threads. Now it works like a charm.

In my opinion this was a architecture problem and not strictly programming related. I hope I help someone in the future with this.