Added maxTargetLimit for a cap that defines how many targets are scanned

at the same time.

1 files changed, 12 insertions, 2 deletions

diff --git a/src/main/java/com/it_jaros/network_scanner/Scanner.java b/src/main/java/com/it_jaros/network_scanner/Scanner.java
index 81cbe1b..7ee0276 100644
--- a/src/main/java/com/it_jaros/network_scanner/Scanner.java
+++ b/src/main/java/com/it_jaros/network_scanner/Scanner.java
@@ -26,12 +26,14 @@ public class Scanner {
     private final int timeoutInMillis;
     private final long delayInNanos;
     private final int maxWorkersPerHost;
+    private final int maxTargetsLimit;
 
-    public Scanner(int socketLimit, int timeoutInMillis, int delayInMillis, int maxWorkersPerHost) {
+    public Scanner(int socketLimit, int timeoutInMillis, int delayInMillis, int maxWorkersPerHost, int maxTargetsLimit) {
         this.timeoutInMillis = timeoutInMillis;
         this.delayInNanos = TimeUnit.MILLISECONDS.toNanos(Math.max(0, delayInMillis));
         this.socketLimit = new Semaphore(socketLimit);
         this.maxWorkersPerHost = maxWorkersPerHost;
+        this.maxTargetsLimit = maxTargetsLimit;
     }
 
     public List<ScanResult> scan(ScanOptions target) {
@@ -43,8 +45,16 @@ public class Scanner {
         progressBar.start();
         try (ExecutorService executor = Executors.newVirtualThreadPerTaskExecutor()) {
             List<Future<ScanResult>> futures = new ArrayList<>();
+            Semaphore maxTargets = new Semaphore(maxTargetsLimit);
             for (String target : targets) {
-                futures.add(executor.submit(() -> scanTarget(target, ports)));
+                maxTargets.acquireUninterruptibly();
+                futures.add(executor.submit(() -> {
+                    try {
+                        return scanTarget(target, ports);
+                    } finally {
+                        maxTargets.release();
+                    }
+                }));
             }
 
             futures.forEach((Future<ScanResult> f) -> {