From d2ab45e7ecdfee71806eb0388527cd50ba96975d Mon Sep 17 00:00:00 2001
From: Matthias Jaros <jarlucmat@mailbox.org>
Date: Mon, 6 Jul 2026 11:05:31 +0200
Subject: Changing scanner from collecting all results to a stream of output.
 Saves RAM and is not necessary to first collect everything

---
 src/main/java/com/it_jaros/jscanner/App.java     |  2 +-
 src/main/java/com/it_jaros/jscanner/Scan.java    | 16 +++-------------
 src/main/java/com/it_jaros/jscanner/Scanner.java | 11 +++++------
 3 files changed, 9 insertions(+), 20 deletions(-)

(limited to 'src')

diff --git a/src/main/java/com/it_jaros/jscanner/App.java b/src/main/java/com/it_jaros/jscanner/App.java
index 700b3f0..42d2321 100644
--- a/src/main/java/com/it_jaros/jscanner/App.java
+++ b/src/main/java/com/it_jaros/jscanner/App.java
@@ -24,7 +24,7 @@ public class App {
         try (Scanner scanner = new Scanner(options)) {
             Scan scan = Scan.create(options);
             addShutdownHook(scanner);
-            printScanResults(scanner.runScan(scan), scan.getPeakConcurrentConnects(), options.showFilteredPorts());
+            scanner.runScan(scan, result -> printPortsResults(result, options.showFilteredPorts()));
         } finally {
             shutdownLatch.countDown();
             removeShutdownHook();
diff --git a/src/main/java/com/it_jaros/jscanner/Scan.java b/src/main/java/com/it_jaros/jscanner/Scan.java
index 75ed349..bdc3f3a 100644
--- a/src/main/java/com/it_jaros/jscanner/Scan.java
+++ b/src/main/java/com/it_jaros/jscanner/Scan.java
@@ -13,23 +13,17 @@ import java.util.stream.Stream;
  */
 public class Scan {
     private final Stream<String> hosts;
-    private final ScanState state;
     private final String ports;
     private final Counter counter;
     private final ProgressBar progressBar;
 
-    private Scan(Stream<String> hosts, String ports, ScanState state, boolean quiet) {
+    private Scan(Stream<String> hosts, String ports, boolean quiet) {
         this.hosts = hosts;
         this.ports = ports;
-        this.state = state;
         this.counter = new Counter();
         this.progressBar = new ProgressBar(quiet);
     }
 
-    public List<ScanResult> getResults() {
-        return this.state.getCopyOfResults();
-    }
-
     public int getPeakConcurrentConnects() {
         return counter.max();
     }
@@ -70,11 +64,11 @@ public class Scan {
     }
 
     private static Scan create(Stream<String> lines, String ports, boolean quiet) {
-        return new Scan(lines, ports, new ScanState(), quiet);
+        return new Scan(lines, ports, quiet);
     }
 
     public static Scan create(List<String> hostsArgv, String ports, boolean quiet) {
-        return new Scan(hostsArgv.stream(), ports, new ScanState(), quiet);
+        return new Scan(hostsArgv.stream(), ports, quiet);
     }
 
     public Stream<String> getHosts() {
@@ -105,8 +99,4 @@ public class Scan {
     public void decSocketCounter() {
         counter.dec();
     }
-
-    public void addScanResult(ScanResult scanResult) {
-        state.addScanResult(scanResult);
-    }
 }
diff --git a/src/main/java/com/it_jaros/jscanner/Scanner.java b/src/main/java/com/it_jaros/jscanner/Scanner.java
index 40c2e23..3e655a5 100644
--- a/src/main/java/com/it_jaros/jscanner/Scanner.java
+++ b/src/main/java/com/it_jaros/jscanner/Scanner.java
@@ -10,6 +10,7 @@ import java.util.concurrent.*;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.atomic.AtomicLong;
+import java.util.function.Consumer;
 import java.util.function.Function;
 
 public class Scanner implements AutoCloseable {
@@ -54,9 +55,8 @@ public class Scanner implements AutoCloseable {
      * Starts a given scan.
      *
      * @param scan
-     * @return
      */
-    public List<ScanResult> runScan(final Scan scan) {
+    public void runScan(final Scan scan, final Consumer<ScanResult> consumer) {
         if (scan == null) {
             throw new IllegalArgumentException("Scan argument cannot be null");
         }
@@ -88,9 +88,8 @@ public class Scanner implements AutoCloseable {
                 // No matter what happens we have to free the resources after getting ScanResult
                 try {
                     ScanResult result = finishedHost.get();
-                    // we only want results that give value and not cost RAM for nothing
-                    if (!result.openPorts().isEmpty() || !result.filteredPorts().isEmpty()) {
-                        scan.addScanResult(result);
+                    if (result != null) {
+                        consumer.accept(result);
                     }
                 } finally {
                     state.activeWorkers().release();
@@ -104,7 +103,6 @@ public class Scanner implements AutoCloseable {
         }
 
         scan.stop();
-        return scan.getResults();
     }
 
     /**
@@ -155,6 +153,7 @@ public class Scanner implements AutoCloseable {
 
                 try {
                     PortResult portResult = portResultFuture.get();
+                    if (portResult == null) continue;
                     switch (portResult.getState()) {
                         case OPEN -> {
                             // bitset is not thread-safe, so it is set
-- 
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