From ae609dbf64f3556336c1bb961d5a4ae9484bd90b Mon Sep 17 00:00:00 2001
From: "Norbraten, Terry" <tdnorbra@nps.edu>
Date: Mon, 27 Jul 2020 17:46:47 -0700
Subject: [PATCH] no object creation in loops, use NIO
---
.../MulticastReceiver.java | 130 ++++++++++--------
.../MulticastSender.java | 84 ++++++-----
2 files changed, 124 insertions(+), 90 deletions(-)
diff --git a/examples/src/UdpMulticastHttpExamples/MulticastReceiver.java b/examples/src/UdpMulticastHttpExamples/MulticastReceiver.java
index a4e18df39a..15bf2a0b09 100644
--- a/examples/src/UdpMulticastHttpExamples/MulticastReceiver.java
+++ b/examples/src/UdpMulticastHttpExamples/MulticastReceiver.java
@@ -1,10 +1,14 @@
package UdpMulticastHttpExamples;
+import edu.nps.moves.dis7.utilities.DisThreadedNetIF;
import java.io.*;
import java.net.*;
+import java.nio.ByteBuffer;
+import java.util.logging.Level;
+import java.util.logging.Logger;
/**
- * Looks a lot like UdpReceiver. Start this before launching MulticastSender.
+ * Looks a lot like UdpReceiver. Start this before launching MulticastSender.
*
* @author mcgredo
* @author brutzman
@@ -14,81 +18,97 @@ public class MulticastReceiver {
// reserved range for all IPv4 multicast: 224.0.0.0 through 239.255.255.255
// https://en.wikipedia.org/wiki/Multicast_address
// https://www.iana.org/assignments/multicast-addresses/multicast-addresses.xhtml
-
- public static final String MULTICAST_ADDRESS = "239.1.2.15";
- public static final int DESTINATION_PORT = 1718;
- /** Time to live: how many router-decrement levels can be crossed */
- public static final int TTL = 10;
-
- final private static boolean infiniteReadLoop = true;
-
- public static void main(String[] args)
- {
- try
- {
- System.out.println("MulticastReceiver started...");
+ public static final String MULTICAST_ADDRESS = "239.1.2.15";
+ public static final int DESTINATION_PORT = 1718;
+
+ /**
+ * Time to live: how many router-decrement levels can be crossed
+ */
+ public static final int TTL = 10;
+
+ private static final boolean INFINITE_READ_LOOP = true;
+ private static NetworkInterface ni;
+
+ public static void main(String[] args) {
+
+ MulticastSocket multicastSocket = null;
+ InetSocketAddress group = null;
+ ByteBuffer buffer = ByteBuffer.allocate(1500);
+ DatagramPacket packet = new DatagramPacket(buffer.array(), buffer.capacity());
+ try {
+ System.out.println("MulticastReceiver started...");
+
// This is a java/IPv6 problem. You should also add it to the
// arguments used to start the app, eg -Djava.net.preferIPv4Stack=true
// set in the "run" section of preferences. Also, typically
// netbeans must be restarted after these settings.
// https://stackoverflow.com/questions/18747134/getting-cant-assign-requested-address-java-net-socketexception-using-ehcache
System.setProperty("java.net.preferIPv4Stack", "true");
-
- MulticastSocket multicastSocket = new MulticastSocket(DESTINATION_PORT);
+
+ multicastSocket = new MulticastSocket(DESTINATION_PORT);
multicastSocket.setTimeToLive(TTL);
InetAddress multicastAddress = InetAddress.getByName(MULTICAST_ADDRESS);
+
+ group = new InetSocketAddress(multicastAddress, DESTINATION_PORT);
+
// Join group useful on receiving side
- multicastSocket.joinGroup(multicastAddress);
+ multicastSocket.joinGroup(group, ni = DisThreadedNetIF.findIpv4Interface());
// You can join multiple groups here
+
System.out.println("Multicast address/port: " + multicastAddress.getHostAddress() + "/" + DESTINATION_PORT);
System.out.println("Multicast packets received log:");
-
- int count = 0; // initialize
-
- while(true)
- {
- byte[] packetArray = new byte[1500]; // note use of typical MTU value
- DatagramPacket packet = new DatagramPacket(packetArray, packetArray.length);
-
+
+ int index, count = 0; // initialize
+ float firstFloat, secondFloat;
+ StringBuilder firstCharacters = new StringBuilder();
+ char nextChar;
+
+ while (true) {
multicastSocket.receive(packet);
count++;
-
- ByteArrayInputStream bais = new ByteArrayInputStream(packet.getData());
- DataInputStream dis = new DataInputStream(bais);
- String firstCharacters = new String();
- char nextChar = ' ';
- while (nextChar != ';') // read and build string until terminator ; found
- {
- nextChar = dis.readChar();
- firstCharacters += nextChar;
- }
- if (firstCharacters.contains(MulticastSender.QUIT_SENTINEL))
- {
- System.out.println("Received sentinel \"" + MulticastSender.QUIT_SENTINEL + "\"");
- if (!infiniteReadLoop)
+
+ nextChar = ' ';
+ while (nextChar != ';') // read and build string until terminator ; found
+ {
+ nextChar = buffer.getChar();
+ firstCharacters.append(nextChar);
+ }
+ if (firstCharacters.toString().contains(MulticastSender.QUIT_SENTINEL)) {
+ System.out.println("Received sentinel \"" + MulticastSender.QUIT_SENTINEL + "\"");
+ if (!INFINITE_READ_LOOP) {
break; // exit out of reading loop
- }
- int index = dis.readInt();
- float firstFloat = dis.readFloat();
- float secondFloat = dis.readFloat();
-
- if (count < 10) System.out.print(" "); // prettier output formatting
+ }
+ }
+ index = buffer.getInt();
+ firstFloat = buffer.getFloat();
+ secondFloat = buffer.getFloat();
+ buffer.clear();
+
+ if (count < 10) {
+ System.out.print(" "); // prettier output formatting
+ }
System.out.print(count + ". \"" + firstCharacters + "\" "); // wrap string in quote marks
System.out.println("index=" + index + ", firstFloat=" + firstFloat + " secondFloat=" + secondFloat);
-
+
System.out.println("MulticastReceiver loop complete.");
+ firstCharacters.setLength(0);
}
- }
- catch(IOException e)
+ } catch (IOException e) {
+ System.err.println("Problem with MulticastReceiver, see exception trace:");
+ System.err.println(e);
+ } finally // clean up after exit condition
{
- System.out.println("Problem with MulticastReceiver, see exception trace:");
- System.out.println(e);
- }
- finally // clean up after exit condition
- {
- // socket/database/completion cleanup code can go here, if needed.
+ if (multicastSocket != null && !multicastSocket.isClosed()) {
+ try {
+ multicastSocket.leaveGroup(group, ni);
+ } catch (IOException ex) {
+ Logger.getLogger(MulticastReceiver.class.getName()).log(Level.SEVERE, null, ex);
+ }
+ multicastSocket.close();
+ }
+ // socket/database/completion cleanup code can go here, if needed.
System.out.println("MulticastReceiver finally block, complete.");
- }
+ }
}
}
diff --git a/examples/src/UdpMulticastHttpExamples/MulticastSender.java b/examples/src/UdpMulticastHttpExamples/MulticastSender.java
index ae27b55f4c..7aaa9e4761 100644
--- a/examples/src/UdpMulticastHttpExamples/MulticastSender.java
+++ b/examples/src/UdpMulticastHttpExamples/MulticastSender.java
@@ -1,5 +1,6 @@
package UdpMulticastHttpExamples;
+import edu.nps.moves.dis7.utilities.DisThreadedNetIF;
import java.io.*;
import java.net.*;
@@ -28,9 +29,17 @@ public class MulticastSender {
public static final String QUIT_SENTINEL = "QUIT QUIT QUIT!";
- @SuppressWarnings("SleepWhileInLoop")
- public static void main(String[] args)
+ @SuppressWarnings("SleepWhileInLoop")
+ public static void main(String[] args) throws IOException
{
+ MulticastSocket multicastSocket = null;
+
+ // Put together a message with binary content. "ByteArrayOutputStream"
+ // is a java.io utility that lets us put together an array of binary
+ // data, which we put into the UDP packet.
+ ByteArrayOutputStream baos = new ByteArrayOutputStream();
+ DataOutputStream dos = new DataOutputStream(baos);
+
try
{
System.out.println("MulticastSender started...");
@@ -42,53 +51,58 @@ public class MulticastSender {
System.setProperty("java.net.preferIPv4Stack", "true");
// multicast group we are sending to--not a single host
- MulticastSocket multicastSocket = new MulticastSocket(DESTINATION_PORT);
+ multicastSocket = new MulticastSocket(DESTINATION_PORT);
multicastSocket.setTimeToLive(TTL); // time to live reduces scope of transmission
InetAddress multicastAddress = InetAddress.getByName(MULTICAST_ADDRESS);
System.out.println("Multicast address/port: " + multicastAddress.getHostAddress() + "/" + DESTINATION_PORT);
+
+ InetSocketAddress group = new InetSocketAddress(multicastAddress, DESTINATION_PORT);
// Join group useful on receiving side
- multicastSocket.joinGroup(multicastAddress);
+ multicastSocket.joinGroup(group, DisThreadedNetIF.findIpv4Interface());
// You can join multiple groups here
+ DatagramPacket packet;
+ byte[] buffer;
+
for (int index = 0; index < LOOPSIZE; index++)
{
- // Put together a message with binary content. "ByteArrayOutputStream"
- // is a java.io utility that lets us put together an array of binary
- // data, which we put into the UDP packet.
- ByteArrayOutputStream baos = new ByteArrayOutputStream();
- DataOutputStream dos = new DataOutputStream(baos);
+ // Put together an updated packet to send
+ if (index < LOOPSIZE - 1)
+ {
+ // Put together an updated packet to send
+ dos.writeChars(System.getProperty("user.name") + ": ");
+ dos.writeChars("MulticastSender packet " + Integer.toString(index) + ";"); // string chars for readability
+ dos.writeInt (index); // arbitrary data, needs Java or byte-alignment to read
+ dos.writeFloat(17.0f); // arbitrary data, needs Java or byte-alignment to read
+ dos.writeFloat(23.0f); // arbitrary data, needs Java or byte-alignment to read
+ }
+ else dos.writeChars(QUIT_SENTINEL + ";"); // note string must include ; semicolon as termination sentinel
+
+ buffer = baos.toByteArray();
+ packet = new DatagramPacket(buffer, buffer.length, multicastAddress, DESTINATION_PORT);
- // Put together an updated packet to send
- if (index < LOOPSIZE - 1)
- {
- // Put together an updated packet to send
- dos.writeChars(System.getProperty("user.name") + ": ");
- dos.writeChars("MulticastSender packet " + Integer.toString(index) + ";"); // string chars for readability
- dos.writeInt (index); // arbitrary data, needs Java or byte-alignment to read
- dos.writeFloat(17.0f); // arbitrary data, needs Java or byte-alignment to read
- dos.writeFloat(23.0f); // arbitrary data, needs Java or byte-alignment to read
- }
- else dos.writeChars(QUIT_SENTINEL + ";"); // note string must include ; semicolon as termination sentinel
-
- byte[] buffer = baos.toByteArray();
- DatagramPacket packet = new DatagramPacket(buffer, buffer.length, multicastAddress, DESTINATION_PORT);
-
- multicastSocket.send(packet);
- System.out.println("Sent multicast packet " + index + " of " + LOOPSIZE);
-
- // How fast does this go? Does UDP try to slow it down, or does
- // this cause network problems? (hint: yes for an unlimited send
- // rate, unlike TCP). How do you know on the receiving side
- // that you haven't received a duplicate UDP packet, out of
- // order packet, or dropped packet? Necessary considerations.
- Thread.sleep(1000); // Send 100, one per second
+ multicastSocket.send(packet);
+ System.out.println("Sent multicast packet " + index + " of " + LOOPSIZE);
+ baos.reset();
+
+ // How fast does this go? Does UDP try to slow it down, or does
+ // this cause network problems? (hint: yes for an unlimited send
+ // rate, unlike TCP). How do you know on the receiving side
+ // that you haven't received a duplicate UDP packet, out of
+ // order packet, or dropped packet? Necessary considerations.
+ Thread.sleep(1000); // Send 100, one per second
}
System.out.println("MulticastSender complete.");
}
catch(IOException | InterruptedException e)
{
- System.out.println("Problem with MulticastSender, see exception trace:");
- System.out.println(e);
+ if (multicastSocket != null)
+ multicastSocket.close();
+
+ dos.close();
+
+ System.err.println("Problem with MulticastSender, see exception trace:");
+ System.err.println(e);
}
}
--
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