jscanner

commit ab71c5ad14512f2a33e1c91f510c4c00c8026ff7
parent b38ac9bda18b619e9177db1a71b1370552a8a0c3
Author: Matthias Jaros <jaros@mailbox.org>
Date:   Fri,  3 Jul 2026 12:21:01 +0200

Added comments and minor refactoring

Diffstat:
M
src/main/java/com/it_jaros/jscanner/Scan.java
 | 
3
+++
M
src/main/java/com/it_jaros/jscanner/Scanner.java
 | 
16
++++++++++++----

2 files changed, 15 insertions(+), 4 deletions(-)
diff --git a/src/main/java/com/it_jaros/jscanner/Scan.java b/src/main/java/com/it_jaros/jscanner/Scan.java
@@ -8,6 +8,9 @@ import java.nio.file.NoSuchFileException;
 import java.nio.file.Path;
 import java.util.List;
 
+/**
+ * Object holder for stateful volatile data during scan
+ */
 public class Scan {
     private final List<String> hosts;
     private final ScanState state;
diff --git a/src/main/java/com/it_jaros/jscanner/Scanner.java b/src/main/java/com/it_jaros/jscanner/Scanner.java
@@ -49,6 +49,11 @@ public class Scanner implements AutoCloseable {
     }
 
 
+    /**
+     * Starts a given scan.
+     * @param scan
+     * @return
+     */
     public List<ScanResult> runScan(Scan scan) {
         if (scan == null) {
             throw new IllegalArgumentException("Scan argument cannot be null");
@@ -61,18 +66,20 @@ public class Scanner implements AutoCloseable {
         int hostsToProcess = hostsInQueue.size();
         int activeHostWorkers = 0;
         while ((hostsToProcess > 0 && !cancelled) || activeHostWorkers > 0) {
-            // process queue
             while (
                     !hostsInQueue.isEmpty() // continue as long as we have hosts to process
                             && activeHostWorkers < maxHostsLimit // limit is not reached
                             && !cancelled // and scanner not closed
             ) {
-                activeHostWorkers++;
+                // here we are filling the completion service
+                // host <-> virtual thread
                 final String host = hostsInQueue.poll();
+                activeHostWorkers++;
                 completionService.submit(() -> scanHostPorts(host, scan.getPorts(), scan));
             }
 
             try {
+                // let's check for results and give add them to our scan data holder object
                 Future<ScanResult> finishedHost = completionService.poll(10, TimeUnit.MILLISECONDS);
                 if (finishedHost == null) {
                     continue;
@@ -118,8 +125,10 @@ public class Scanner implements AutoCloseable {
                             && activePerHostWorkers < maxWorkersPerHost // and we have not reached our limit 
                             && !cancelled // and the scanner is not about to close
             ) {
-                activePerHostWorkers++;
+                // Here we are filling the completion service
+                // port <-> virtual thread
                 final int currentPort = portRange.next();
+                activePerHostWorkers++;
                 completionService.submit(() -> {
                     waitForSlot(portSlotFactory);
                     return checkPort(host, currentPort, scan);
@@ -133,7 +142,6 @@ public class Scanner implements AutoCloseable {
                 }
 
                 PortResult portResult = portResultFuture.get();
-
                 activePerHostWorkers--;
                 portsToProcess--;
                 progress.done().incrementAndGet();