How is NioSelectedKeySet intended to be used?

[HKBUSeanTYH]

I am looking for help on how to use NioSelectedKeySet and its intended usage. Should I copy the TransportPoller and modify? What if I want to use multiple selectors? with static Fields in the transport poller what would happen if i instantiate multiple transport pollers?

[HKBUSeanTYH]

I have tried the following which is to extend the TransportPoller provided and create methods to register channels to selector and to perform select operations. Is this the correct/intended usage?

public class SelectorOptimizer extends TransportPoller {
    private final String SELECT_MODE;
    private final int SELECT_TIMEOUT;

    public SelectorOptimizer(String selectMode, int selectTimeout){
        super();
        this.SELECT_MODE = selectMode;
        this.SELECT_TIMEOUT = selectTimeout;
    }
    
    public void registerChannel(UDPChannel channel) throws ClosedChannelException {
        channel.getCHANNEL().register(this.selector, SelectionKey.OP_READ, channel);
    }
    
    public SelectionKey[] performSelection() throws IOException {
        this.selectedKeySet.clear();
        int readyKeys;
        if (SELECT_MODE.equals("BLOCK")) {
            readyKeys = this.selector.select();
        } else if (SELECT_MODE.equals("TIMEOUT")) {
            if (SELECT_TIMEOUT != 0) {
                readyKeys = this.selector.select(SELECT_TIMEOUT);
            } else {
                readyKeys = this.selector.select(5000);
            }
        } else {
            readyKeys = this.selector.selectNow();
        }

        return selectedKeySet.keys();
    }
}

[mikeb01]

NioSelectedKeySet is only intended to be using with TransportPoller as a workaround to avoid the memory allocation that occurs in Selector#selectedKeys. If you are running JDK 11 or later, then you should use Selector#select(Consumer<SelectionKey> action) instead of NioSelectedKeySet.