Question

I’m trying to move my client network processing code into another thread, so it doesn’t hang the main thread when processing a packet.

Basically I have an ArrayList of packets received. The Thread runs an infinite while loop, processing any new packets. However this puts my CPU up to 100%, because even if there are no new packets, it still loops continuously.

What I want to do, is have the processing thread sleeping, and my thread, notify it, when there are new packets.

I’m coding this in Java.

EDIT:

This is what I am striving to achieve –

// Main Thread
// Listener
public void newPacketReceived(){
    receiverThread.addNewPacketToProcessingQueue(null);

}

// Receiver Thread
ArrayList<GamePacket> processingQueue = new ArrayList<GamePacket>();

public void addNewPacketToProcessingQueue(GamePacket packet){
    processingQueue.add(packet);
    this.notify();
}

public void run(){
    while(true){
        // Process Packets
        this.sleep(); // Sleep until thread is notified 
    }
}

Answer 1

Rather than using an ArrayList, use a BlockingQueue of some description (e.g. LinkedBlockingQueue). That’s designed for exactly this sort of use case.

The producer code will use offer to offer a new element, and the processing thread will use poll with a timeout to block (cheaply) until an element is present.