Added swap method

CircularArrayList.java

package mishael;

import java.util.ArrayList;
import java.util.Random;

public class CircularArrayList<Generic>
{
	private ArrayList<Generic> a;

	public CircularArrayList()
	{
		this.a = new ArrayList<Generic>();
	}

	public CircularArrayList(Generic first)
	{
		this.a = new ArrayList<Generic>();
		this.a.add(first);
	}

	public CircularArrayList(Generic[] first)
	{
		this.a = new ArrayList<Generic>();
		for (Generic temp : first)
			this.a.add(temp);
	}

	public void add(Generic o)
	{
		this.a.add(o);
	}

	public Generic get(int index)
	{
		if (this.a.size() == 0)
			return null;
		return this.a.get(index % this.a.size());
	}

	public void set(int index, Generic o)
	{
		if (this.a.size() == 0)
			return;
		this.a.set(index % this.a.size(), o);
	}
	
	public void swap(int index1, int index2)
	{
		Generic temp=get(index2);
		set(index2, get(index1));
		set(index1, temp);
	}
	
	public void mixup(int swaps)
	{
		for(int i=1; i<=swaps; i++)
			swap(new Random().nextInt(this.a.size()), new Random().nextInt(this.a.size()));
	}

	public String toString()
	{
		String st = "[";
		if (this.a.size() != 0)
			st += this.a.get(0).toString();
		else
			return "[Empty]";
		for (int i = 1; i < this.a.size(); i++)
			st += ", " + this.a.get(i).toString();
		st += "]";
		return st;
	}

	public static void main(String[] args)
	{
		CircularArrayList<Integer> test = new CircularArrayList<Integer>(new Integer[]{ 0, 1, 2 });
		System.out.println(test.toString());
		test.swap(0, 2);
		System.out.println(test.toString());
		test.swap(0, 3);
		System.out.println(test.toString());
		test.mixup(10);
		System.out.println(test.toString());
	}
}