From 46c9efab50810dd755087c97a3bc06f9e7082b56 Mon Sep 17 00:00:00 2001
From: "Norbraten, Terry" <tdnorbra@nps.edu>
Date: Mon, 27 Jul 2020 13:34:47 -0700
Subject: [PATCH] no object creation in loops
---
.../UdpMulticastHttpExamples/UdpReceiver.java | 44 ++++++++++++++-----
.../UdpMulticastHttpExamples/UdpSender.java | 27 ++++++++----
2 files changed, 51 insertions(+), 20 deletions(-)
diff --git a/examples/src/UdpMulticastHttpExamples/UdpReceiver.java b/examples/src/UdpMulticastHttpExamples/UdpReceiver.java
index 178b785722..5b23f76d15 100644
--- a/examples/src/UdpMulticastHttpExamples/UdpReceiver.java
+++ b/examples/src/UdpMulticastHttpExamples/UdpReceiver.java
@@ -2,6 +2,7 @@ package UdpMulticastHttpExamples;
import java.io.*;
import java.net.*;
+
/**
* An example of receiving UDP packets. Since very often both the
* sender and receiver are on the same host we use different ports
@@ -20,36 +21,55 @@ public class UdpReceiver
/**
* @param args the command line arguments
+ * @throws java.io.IOException
*/
- public static void main(String[] args)
+ public static void main(String[] args) throws IOException
{
+ DatagramSocket udpSocket = null;
+ DataInputStream dis = null;
+ int packetCount = 0;
+
try
{
- System.out.println("UdpReceiver started...");
+ System.out.println(UdpReceiver.class.getName() + " started...");
+
// Create a UDP socket
- DatagramSocket udpSocket = new DatagramSocket(RECEIVING_PORT);
+ udpSocket = new DatagramSocket(RECEIVING_PORT);
+ udpSocket.setReceiveBufferSize(1500);
+ udpSocket.setBroadcast(false); // we're just receiving here
+
+ byte[] receiveBuffer = new byte[udpSocket.getReceiveBufferSize()];
+ DatagramPacket receivePacket = new DatagramPacket(receiveBuffer, receiveBuffer.length);
+
+ InputStream bais;
+ float first, second;
// You need a new receiving packet to read from every packet received
while (true)
{
- byte[] receiveBuffer = new byte[1500];
- DatagramPacket receivePacket = new DatagramPacket(receiveBuffer, receiveBuffer.length);
udpSocket.receive(receivePacket);
// Decode the contents by extracting the data from the packet
- ByteArrayInputStream bais = new ByteArrayInputStream(receivePacket.getData());
- DataInputStream dis = new DataInputStream(bais);
+ bais = new ByteArrayInputStream(receivePacket.getData());
+ dis = new DataInputStream(bais);
// What happens if you read an integer? Two double values? ***
- float first = dis.readFloat(); // alternatives: readFloat(); readInt(); dis.readUTF();
- float second = dis.readFloat();
- System.out.println("first value: " + first + " second value: " + second);
+ first = dis.readFloat(); // alternatives: readFloat(); readInt(); dis.readUTF();
+ second = dis.readFloat();
+
+ System.out.println("first value: " + first + " second value: " + second + " packet count = " + ++packetCount);
}
}
catch(IOException e)
{
- System.out.println("Problem with UdpReceiver, see exception trace:");
- System.out.println(e);
+ if (udpSocket != null)
+ udpSocket.close();
+
+ if (dis != null)
+ dis.close();
+
+ System.err.println("Problem with UdpReceiver, see exception trace:");
+ System.err.println(e);
}
}
}
diff --git a/examples/src/UdpMulticastHttpExamples/UdpSender.java b/examples/src/UdpMulticastHttpExamples/UdpSender.java
index 18afda921b..db8b923a65 100644
--- a/examples/src/UdpMulticastHttpExamples/UdpSender.java
+++ b/examples/src/UdpMulticastHttpExamples/UdpSender.java
@@ -21,22 +21,27 @@ public class UdpSender
public static final int RECEIVING_PORT = 1415;
public static final String DESTINATION_HOST = "localhost";
- @SuppressWarnings("SleepWhileInLoop")
- public static void main(String[] args)
+ @SuppressWarnings("SleepWhileInLoop")
+ public static void main(String[] args) throws IOException
{
+ DatagramSocket udpSocket = null;
+ DataOutputStream dos = null;
+
try
{
System.out.println("UdpSender started...");
+
// Create a UDP socket
- DatagramSocket udpSocket = new DatagramSocket(SENDING_PORT);
+ udpSocket = new DatagramSocket(SENDING_PORT);
// 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);
- // alternatives: writeFloat(17.0f); writeInt(17); writeUTF("\"hello MV3500 no really\"");
+ dos = new DataOutputStream(baos);
+
+ // alternatives: writeFloat(17.0f); writeInt(17); writeUTF("\"hello MV3500 no really\"");
dos.writeFloat(17.0f);
dos.writeFloat(24.0f);
byte[] buffer = baos.toByteArray();
@@ -58,14 +63,20 @@ public class UdpSender
{
udpSocket.send(packet);
Thread.sleep(1000); // Send 100, one per second
- System.out.println("Bert Sent packet " + index + " of 100");
+ System.out.println("Bert sent packet " + index + " of 100");
}
System.out.println("UdpSender complete.");
}
catch (IOException | InterruptedException e)
{
- System.out.println("Problem with UdpSender, see exception trace:");
- System.out.println(e);
+ if (udpSocket != null)
+ udpSocket.close();
+
+ if (dos != null)
+ dos.close();
+
+ System.err.println("Problem with UdpSender, see exception trace:");
+ System.err.println(e);
}
}
}
--
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