From 4b39ad9ba44f39e4c68d3592b1295f0044315f7d Mon Sep 17 00:00:00 2001
From: Matthias Jaros <jarlucmat@mailbox.org>
Date: Wed, 5 Aug 2026 17:42:08 +0200
Subject: Removed usage of selector and selectionkey and instead use
 locksupport and wait logic to utilize virtual threads park mechanism for
 performance improvement

---
 src/main/java/com/it_jaros/jscanner/Scanner.java | 44 +++++++++++++-----------
 1 file changed, 23 insertions(+), 21 deletions(-)

diff --git a/src/main/java/com/it_jaros/jscanner/Scanner.java b/src/main/java/com/it_jaros/jscanner/Scanner.java
index 5277327..01185bb 100644
--- a/src/main/java/com/it_jaros/jscanner/Scanner.java
+++ b/src/main/java/com/it_jaros/jscanner/Scanner.java
@@ -3,8 +3,6 @@ package com.it_jaros.jscanner;
 import java.io.IOException;
 import java.io.InputStream;
 import java.net.*;
-import java.nio.channels.SelectionKey;
-import java.nio.channels.Selector;
 import java.nio.channels.SocketChannel;
 import java.nio.charset.StandardCharsets;
 import java.time.Duration;
@@ -12,6 +10,7 @@ import java.util.*;
 import java.util.concurrent.*;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.locks.LockSupport;
 import java.util.function.Consumer;
 import java.util.function.Function;
 
@@ -351,32 +350,35 @@ public class Scanner implements AutoCloseable {
             socketLimit.acquire();
             scan.socketStart();
             try(
-                    SocketChannel socketChannel = SocketChannel.open();
-                    Selector isOpen = Selector.open()
+                    SocketChannel socketChannel = SocketChannel.open()
             ) {
                 socketChannel.configureBlocking(false);
-                SelectionKey isOpenKey = socketChannel.register(isOpen, SelectionKey.OP_CONNECT);
                 socketChannel.connect(new InetSocketAddress(host, port));
-                long deadlineNanos = System.nanoTime() + TimeUnit.MILLISECONDS.toNanos(timeoutInMillis);
-                long waitInMillis = Math.min(timeoutInMillis, 5);
-                while (isOpenKey.isValid() && !isOpenKey.isConnectable()) {
-                    if (isOpen.select(waitInMillis) == 1) {
-                        if (socketChannel.finishConnect()) {
-                            result.setState(PortState.OPEN);
-                            //if (bannerRecognition) {
-                            //    result.setBanner(getBanner(socket));
-                            //}
-                        } else {
-                            result.setState(PortState.FILTERED);
-                        }
+                final long deadlineNanos = System.nanoTime() + TimeUnit.MILLISECONDS.toNanos(timeoutInMillis);
+                final long waitInNanos = TimeUnit.MILLISECONDS.toNanos(1000);
+                boolean isConnected = false;
+                while (!cancelled && !isConnected) {
+                    long remainingNanos = deadlineNanos - System.nanoTime();
+                    if (remainingNanos <= 0) {
                         break;
                     }
+                    LockSupport.parkNanos(Math.min(waitInNanos, remainingNanos));
+                    isConnected = socketChannel.finishConnect();
+                }
 
-                    if (deadlineNanos - System.nanoTime() < 0) {
-                        result.setState(PortState.FILTERED);
-                        break;
-                    }
+                if (cancelled) {
+                    return result;
+                }
+
+                if (isConnected) {
+                    result.setState(PortState.OPEN);
+                    //if (bannerRecognition) {
+                    //    result.setBanner(getBanner(socket));
+                    //}
+                } else {
+                    result.setState(PortState.FILTERED);
                 }
+
             } catch (SocketTimeoutException ignored) {
                 result.setState(PortState.FILTERED);
             } catch (ConnectException ignored) {
-- 
cgit v1.3.1