MatchingEngineServer.java

import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.atomic.AtomicInteger;

public class MatchingEngineServer {

    private static final int PORT           = 5001;
    private static final int EXPECTED_NODES = 2;

    public static void main(String[] args) throws IOException, InterruptedException {

        // Shared queue between sequence buffer and matching engine
        BlockingQueue<Order> queue = new ArrayBlockingQueue<>(200_000);

        // Phase 3 — analytics and storage
        AnalyticsModule analytics = new AnalyticsModule();
        StorageLayer    storage   = new StorageLayer();

        MatchingEngineUI ui = new MatchingEngineUI(); // <--- ADD THIS
        ui.setVisible(true);

        analytics.setUI(ui);

        // Matching engine — same core as Phase 1
        MatchingEngine engine = new MatchingEngine(queue);
        engine.setAnalytics(analytics);
        engine.setStorage(storage);
        engine.setUI(ui);

        // Phase 3 — sequence buffer ensures in-order delivery to engine
        SequenceBuffer sequenceBuffer = new SequenceBuffer(queue);

        // Start background threads
        analytics.start();
        storage.start();
        engine.start();

        AtomicInteger connected = new AtomicInteger(0);
        Thread[]      handlers  = new Thread[EXPECTED_NODES];

        System.out.printf("[Server] Listening on port %d, waiting for %d nodes...%n",
            PORT, EXPECTED_NODES);

        try (ServerSocket serverSocket = new ServerSocket(PORT)) {
            for (int i = 0; i < EXPECTED_NODES; i++) {
                Socket clientSocket = serverSocket.accept();
                String name         = "Node-" + connected.incrementAndGet();
                handlers[i]         = new ClientHandler(clientSocket, sequenceBuffer, name);
                handlers[i].start();
                System.out.printf("[Server] %s connected. (%d/%d)%n",
                    name, connected.get(), EXPECTED_NODES);
            }
        } // ServerSocket closes here — no new connections accepted

        // Wait for all node connections to finish
        for (Thread h : handlers) h.join();

        // Small buffer for last orders to arrive through sequence buffer
        Thread.sleep(300);

        // Signal engine to shut down
        queue.put(Order.POISON_PILL);
        System.out.println("[Server] All nodes done. Poison pill sent.");

        engine.join();
        System.out.println("[Server] Shutdown complete.");
    }
}