The document describes code to add a timeout mechanism to a Receiver class. The Receiver should wait for 4 timeouts of 5 seconds each, displaying messages at each timeout. If a message is received during the timeouts, it should display the message and terminate. If no message is received within 20 seconds, it should display a final message before terminating.

1. Add code to the following class:
Receiver
to impose a four times timeout of 5 seconds. On the expiration
of first, second, and third timeout the following messages
should be displayed on the console of the
Receiver
:
It is 5 seconds I am waiting.
It is 10 seconds I am waiting.
It is 15 seconds I am waiting.
On the expiration of fourth timeout the following message
should be displayed on the console of the
Receiver
and the
Receiver
should be terminated:
It is 20 seconds I am waiting.
I waited 20 seconds to get your message. But you did not send
it.
If the
Sender
sends its message during these time periods the Receiver
should displays the message and terminates. The following are
the result of five outputs of the
Receiver
:
Output 1: When the
Sender
sends its message before the expiration of 5 seconds:
Let us go to a movie

2. Output 2: When the
Sender
sends its message before the expiration of 10 seconds:
It is 5 seconds I am waiting.
Let us go to a movie
Output 3: When the
Sender
sends its message before the expiration of 15 seconds:
It is 5 seconds I am waiting.
It is 10 seconds I am waiting.
Let us go to a movie
Output 4: When the
Sender
sends its message before the expiration of 20 seconds:
It is 10 seconds I am waiting.
It is 15 seconds I am waiting.
Let us go to a movie
Output 5: When the
Sender
either sends its message after 20 seconds or does not send at
all:
It is 5 seconds I am waiting.
It is 10 seconds I am waiting.
It is 15 seconds I am waiting.
It is 20 seconds I am waiting.
I waited 20 seconds to get your message. I do not wait anymore.
Note: This question is similar (not the same) as exercise 4 in
chapter 4 of your book.
Note: Only copy/paste the class:
Receiver
class under the word:
Answer

3. .
Hints:
1.
You need to call the java method:
setSoTimeout(5000)
of class:
DatagramSocket
.
2.
You need an extra catch-block with the exception class:
SocketTimeoutException
.
3.
You need a loop that iterates at most four times every 5
seconds.
Sender
:
import
java.io.*;
import
java.net.*;
public
class
Sender {
public
static
void
main(String[]
args

4. )
throws
IOException {
// This class is complete, do not change it.
try
{
String
message
=
"Let us go to a movie"
;
byte
[]
buffer
=
message
.getBytes();
int
port
= 16790;
InetAddress
host
= InetAddress.
getByName
(
"localhost"
);
DatagramSocket
serverSocket
=
new

5. DatagramSocket();
DatagramPacket
datagram
=
new
DatagramPacket(
buffer
,
buffer
.
length
,
host
,
port
);
serverSocket
.send(
datagram
);
serverSocket
.close();
}
catch
(IOException
e
) {
System.
out
.println(
"Error: "
+
e

6. );
System.
exit
(0);
}
}
}
Receiver
:
import
java.io.*;
import
java.net.*;
public
class
Receiver {
// Complete this class.
public
static
void
main(String[]
args
)
throws
IOException {
final
int
MAX_LEN
= 100;

7. byte
[]
buffer
=
new
byte
[
MAX_LEN
];
int
port
= 16790;
DatagramPacket
datagram
=
new
DatagramPacket(
buffer
,
buffer
.
length
);
DatagramSocket
clientSocket
=
new
DatagramSocket(
port
);
.......
}
}

8. Answer
:
Receiver
: