From ca276dc879738664910d61650dda715e177da7cd Mon Sep 17 00:00:00 2001
From: Matthias Jaros <jarlucmat@mailbox.org>
Date: Tue, 11 Aug 2026 16:07:59 +0200
Subject: Boundaries: Added PortList class to encapsulate BitSet and thus have
 a clear boundary to the outside world that uses the result

---
 src/main/java/com/it_jaros/jscanner/PortList.java  | 27 ++++++++++++++++++++++
 .../java/com/it_jaros/jscanner/ProgressBar.java    | 14 +++++------
 .../java/com/it_jaros/jscanner/ScanResult.java     | 13 +++++++----
 src/main/java/com/it_jaros/jscanner/Scanner.java   |  8 ++++++-
 4 files changed, 49 insertions(+), 13 deletions(-)
 create mode 100644 src/main/java/com/it_jaros/jscanner/PortList.java

(limited to 'src/main')

diff --git a/src/main/java/com/it_jaros/jscanner/PortList.java b/src/main/java/com/it_jaros/jscanner/PortList.java
new file mode 100644
index 0000000..574d3eb
--- /dev/null
+++ b/src/main/java/com/it_jaros/jscanner/PortList.java
@@ -0,0 +1,27 @@
+package com.it_jaros.jscanner;
+
+import java.util.BitSet;
+import java.util.List;
+
+/**
+ * Encapsulates a port scan result and is immutable
+ */
+public class PortList {
+    private final BitSet ports;
+
+    public PortList(BitSet ports) {
+        this.ports = ports;
+    }
+
+    public List<Integer> getPorts() {
+        return ports.stream().boxed().toList();
+    }
+
+    public boolean isEmpty() {
+        return ports.isEmpty();
+    }
+
+    public int size() {
+        return ports.cardinality();
+    }
+}
diff --git a/src/main/java/com/it_jaros/jscanner/ProgressBar.java b/src/main/java/com/it_jaros/jscanner/ProgressBar.java
index 795c9bb..3a38069 100644
--- a/src/main/java/com/it_jaros/jscanner/ProgressBar.java
+++ b/src/main/java/com/it_jaros/jscanner/ProgressBar.java
@@ -2,7 +2,7 @@ package com.it_jaros.jscanner;
 
 import java.io.BufferedReader;
 import java.io.InputStreamReader;
-import java.util.BitSet;
+import java.util.List;
 import java.util.Map;
 import java.util.concurrent.Executors;
 import java.util.concurrent.ScheduledExecutorService;
@@ -75,12 +75,12 @@ public class ProgressBar {
         sb.append("\n");
         if (!result.openPorts().isEmpty()) {
             sb.append(
-                    String.format("\t (%d) open:\t%s%n", result.openPorts().cardinality(), map(result.openPorts(), result.bannerRecognition()))
+                    String.format("\t (%d) open:\t%s%n", result.openPorts().size(), map(result.openPorts().getPorts(), result.bannerRecognition()))
             );
         }
         if (showFilteredPorts && !result.filteredPorts().isEmpty()) {
             sb.append(
-                    String.format("\t (%d) filtered:\t%s%n", result.filteredPorts().cardinality(), map(result.filteredPorts()))
+                    String.format("\t (%d) filtered:\t%s%n", result.filteredPorts().size(), map(result.filteredPorts().getPorts()))
             );
         }
         sb.append("\n");
@@ -88,12 +88,12 @@ public class ProgressBar {
         System.out.flush();
     }
 
-    private static String map(BitSet ports) {
-        return ports.stream().mapToObj(String::valueOf).collect(Collectors.joining(","));
+    private static String map(List<Integer> ports) {
+        return ports.stream().map(String::valueOf).collect(Collectors.joining(","));
     }
 
-    private static String map(BitSet ports, Map<Integer, ServiceType> bannerRecognition) {
-        return ports.stream().mapToObj(port -> {
+    private static String map(List<Integer> ports, Map<Integer, ServiceType> bannerRecognition) {
+        return ports.stream().map(port -> {
             ServiceType serviceType = bannerRecognition.getOrDefault(port, ServiceType.UNKNOWN);
 
             if (serviceType == ServiceType.UNKNOWN) {
diff --git a/src/main/java/com/it_jaros/jscanner/ScanResult.java b/src/main/java/com/it_jaros/jscanner/ScanResult.java
index 85d9a36..3eb4d0d 100644
--- a/src/main/java/com/it_jaros/jscanner/ScanResult.java
+++ b/src/main/java/com/it_jaros/jscanner/ScanResult.java
@@ -1,19 +1,22 @@
 package com.it_jaros.jscanner;
 
-import java.util.*;
+import java.util.BitSet;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
 
 public record ScanResult(
         String host,
-        BitSet openPorts,
-        BitSet filteredPorts,
+        PortList openPorts,
+        PortList filteredPorts,
         Map<Integer, ServiceType> bannerRecognition,
         List<ScanFailure> errors
 ) {
     public static ScanResult empty(String host) {
         return new ScanResult(
                 host,
-                new BitSet(PortRange.MAX_PORT),
-                new BitSet(PortRange.MAX_PORT),
+                new PortList(new BitSet(PortRange.MAX_PORT)),
+                new PortList(new BitSet(PortRange.MAX_PORT)),
                 Collections.emptyMap(),
                 Collections.emptyList()
         );
diff --git a/src/main/java/com/it_jaros/jscanner/Scanner.java b/src/main/java/com/it_jaros/jscanner/Scanner.java
index fdd011e..7f6b743 100644
--- a/src/main/java/com/it_jaros/jscanner/Scanner.java
+++ b/src/main/java/com/it_jaros/jscanner/Scanner.java
@@ -464,7 +464,13 @@ public class Scanner implements AutoCloseable {
         }
 
         ScanResult build() {
-            return new ScanResult(host, openPorts, filteredPorts, Collections.unmodifiableMap(serviceTypes), Collections.unmodifiableList(scanFailures));
+            return new ScanResult(
+                    host,
+                    new PortList(openPorts),
+                    new PortList(filteredPorts),
+                    Collections.unmodifiableMap(serviceTypes),
+                    Collections.unmodifiableList(scanFailures)
+            );
         }
     }
 }
-- 
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