Java - Socket setTrafficClass() Method

Description

The Java Socket setTrafficClass(int tc) is used to set traffic class or type-of-service octet in the IP header for packets sent from this Socket instance. As the underlying network implementation may ignore this value so applications must consider it as a hint. The allowed value of tc is in the range 0 <= tc <= 255 otherwise an IllegalArgumentException will be thrown.

Declaration

Following is the declaration for java.net.Socket.setTrafficClass(int tc) method.

public void setTrafficClass(int tc) throws SocketException

Parameters

tc − an int value for the bitset.

Return Value

N/A

Exception

SocketException − if there is an error setting the traffic class or type-of-service.

Example 1

The following example shows the usage of Java Socket setTrafficClass() method to set traffic class or type-of-service in the IP header for packets sent from this Socket. As first step, we've created a Socket instance using no argument constructor. Then in order to create a SocketAddress object, we've initialized an InetAddress instance of localhost address. Using InetSocketAddress object, we've created a SocketAddress object and then using bind() method, we bind the address to the socket. Then we're setting the type-of-service value as 25 (range is 0 to 255) using setTrafficClass() method. Once done, we're printing the value using getTrafficClass() method, local port and inetaddress as shown. In the end, we closed the socket using close() method.

package com.tutorialspoint;

import java.io.IOException;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.Socket;
import java.net.SocketAddress;

public class SocketDemo {
   public static void main(String[] args) throws IOException {
      Socket socket = new Socket();  
      InetAddress inetAddress=InetAddress.getByName("localhost");  
      SocketAddress socketAddress=new InetSocketAddress(inetAddress, 6066);  
      socket.bind(socketAddress); 
      socket.setTrafficClass(25); 
      System.out.println("type-of-service: "+socket.getTrafficClass()); 
      System.out.println("Port number: "+socket.getLocalPort()); 
      System.out.println("Inet Address: "+socket.getInetAddress()); 
      socket.close();
   }
}

Output

Let us compile and run the above program, this will produce the following result −

type-of-service: 24
Port number: 6066
Inet Address: null

Example 2

The following example shows the usage of Java Socket setTrafficClass() method to set the value of type-of-service of socket instance. As first step, we've created a Socket instance using no argument constructor. Now, we're printing the type-of-service value using getTrafficClass() method. Then we're setting the type-of-service value as 25 (range is 0 to 255) using setTrafficClass() method and print the same. In the end, we closed the socket using close() method.

package com.tutorialspoint;

import java.io.IOException;
import java.net.Socket;

public class SocketDemo {
   public static void main(String[] args) throws IOException {
      Socket socket = new Socket();  

      System.out.println("type-of-service: "+socket.getTrafficClass());
      socket.setTrafficClass(25);  
      System.out.println("type-of-service: "+socket.getTrafficClass());
      socket.close();
   }
}

Output

Let us compile and run the above program, this will produce the following result −

type-of-service: 0
type-of-service: 24

Example 3

The following example shows the usage of Java Socket setTrafficClass() method to set the value of type-of-service of socket instance, if socket is already closed. As first step, we've created a Socket instance using no argument constructor. Using socket.close(), we're closing the socket. Then we're setting the type-of-service value as 0 (range is 0 to 255) using setTrafficClass() method. Now, we're printing the type-of-service flag using getTrafficClass() method. Then we're setting the type-of-service value as 25 (range is 0 to 255) using setTrafficClass() method and print the same. In the end, we closed the socket using close() method. As socket is already closed, setTrafficClass() method call throws an exception as shown below −

package com.tutorialspoint;

import java.io.IOException;
import java.net.Socket;

public class SocketDemo {
   public static void main(String[] args) throws IOException {
      Socket socket = new Socket();  
      socket.close();	  
      socket.setTrafficClass(0);
      System.out.println("type-of-service: "+socket.getTrafficClass());
      socket.setTrafficClass(25);  
      System.out.println("type-of-service: "+socket.getTrafficClass());
      socket.close();
   }
}

Output

Let us compile and run the above program, this will produce the following result −

Exception in thread "main" java.net.SocketException: Socket is closed
	at java.base/java.net.Socket.setTrafficClass(Socket.java:1397)
	at com.tutorialspoint.SocketDemo.main(SocketDemo.java:10)