Writing pcap file functionality

src/main/java/com/softwaredesign/Main.java

@@ -1,11 +1,10 @@
 package com.softwaredesign;
 
-
 import org.pcap4j.core.NotOpenException;
+import org.pcap4j.core.PcapHandle;
 import org.pcap4j.core.PcapNativeException;
-import org.pcap4j.core.PcapNetworkInterface;
 
-import java.util.List;
+import java.io.IOException;
 
 public class Main {
     public static void main(String[] args) {

src/main/java/com/softwaredesign/NetworkInterfaceHandler.java

@@ -37,7 +37,7 @@ public List<PcapNetworkInterface> getAllDevices() throws IOException {
      * @param maxPackets: Maximum amount of packets to capture from the network interface
      * @throws PcapNativeException
      */
-    public void listenForPacketsOnDevice(PcapNetworkInterface device, int snapshotLength, int readTimeout, int maxPackets) throws PcapNativeException {
+    public PcapHandle listenForPacketsOnDevice(PcapNetworkInterface device, int snapshotLength, int readTimeout, int maxPackets) throws PcapNativeException, NotOpenException {
         final PcapHandle handle = device.openLive(snapshotLength, PromiscuousMode.PROMISCUOUS, readTimeout);
         packets = new ArrayList<>();
 
@@ -56,19 +56,19 @@ public void gotPacket(Packet packet) {
             e.printStackTrace();
         }
 
-        handle.close();
+        return handle;
     }
 
     /**
      * This function allows overloading for the previous listenForPacketsOnDevice function. Sets up default parameters.
      * @param device
      * @throws PcapNativeException
      */
-    public void listenForPacketsOnDevice(PcapNetworkInterface device) throws PcapNativeException {
+    public PcapHandle listenForPacketsOnDevice(PcapNetworkInterface device) throws PcapNativeException, NotOpenException {
         int snapshotLength = 65536; // in bytes
         int readTimeout = 50; // in milliseconds
         int maxPackets = 50;
-        listenForPacketsOnDevice(device, snapshotLength, readTimeout, maxPackets);
+        return listenForPacketsOnDevice(device, snapshotLength, readTimeout, maxPackets);
     }
 
     /**

src/main/java/com/softwaredesign/PcapFileWriterAndReader.java

@@ -0,0 +1,25 @@
+package com.softwaredesign;
+
+import org.pcap4j.core.NotOpenException;
+import org.pcap4j.core.PcapDumper;
+import org.pcap4j.core.PcapHandle;
+import org.pcap4j.core.PcapNativeException;
+import org.pcap4j.packet.Packet;
+
+import java.util.ArrayList;
+
+public class PcapFileWriterAndReader {
+    public void writePacketsToFile(String fileName, ArrayList<Packet> packets, PcapHandle handle) throws NotOpenException, PcapNativeException {
+        PcapDumper dumper = handle.dumpOpen(fileName + ".pcap");
+
+        for (Packet packet: packets) {
+            try {
+                dumper.dump(packet, handle.getTimestamp());
+            } catch (NotOpenException e) {
+                e.printStackTrace();
+            }
+        }
+
+        dumper.close();
+    }
+}