Looking for simple Round robin example

[Meir Yan]

Hello all
i have problem to find "Simple' example source code to understand the round robin algorithm
can some one please point me to some info and simple java code implementation of round robin?
thanks

[Frank Carver]

"Round Robin" usually means just to step round a list of objects.

Imagine a group of people sitting in a circle and passing someting between them. The item passes from one person to another round the circle, potentially forever.

As a code example, try this:

package test;
 
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
 
import junit.framework.TestCase;
 
class Robin {
private int i;
 
public Robin(int i) {
this.i = i;
}
 
public int call() {
return i;
}
}
 
class RoundRobin {
private Iterator<Robin> it;
private List<Robin> list;
 
public RoundRobin(List<Robin> list) {
this.list = list;
it = list.iterator();
}

public int next() {
// if we get to the end, start again
if (!it.hasNext()) {
it = list.iterator();
}
Robin robin = it.next();

return robin.call();
}
}
 
public class RoundRobinTest extends TestCase {
List<Robin> items = new ArrayList<Robin>();
RoundRobin round;

public void testOne() {
items.add(new Robin(1));
round = new RoundRobin(items);
assertEquals(1, round.next());
assertEquals(1, round.next());
}

public void testTwo() {
items.add(new Robin(1));
items.add(new Robin(2));
round = new RoundRobin(items);
assertEquals(1, round.next());
assertEquals(2, round.next());
assertEquals(1, round.next());
assertEquals(2, round.next());
}

public void testThree() {
items.add(new Robin(1));
items.add(new Robin(2));
items.add(new Robin(3));
round = new RoundRobin(items);
assertEquals(1, round.next());
assertEquals(2, round.next());
assertEquals(3, round.next());
assertEquals(1, round.next());
assertEquals(2, round.next());
assertEquals(3, round.next());
}
}

In this case I am using an iterator to step through a list, and starting again when I reach the end.

Does that make any sense?

[Ramesh Sunkara]

hi Frank

Your post is very useful for me thanks for your help

[naniigadu pokiri]

Hi Frank,

You example gives us everything to understand,

Thanks,
Raja