/*
 * Created on Aug 5, 2004
 */
package hashing;

import java.util.Iterator;
import java.util.Random;

/** Producer of a series of random strings with the format of IP addresses,
 * xxx.xxx.xxx.xxx.  This class is an Iterator, so it can be used with the
 * familiar pattern:
 *  * <br />
 * <pre>
 Iterator sIter = new RandomAlphaStringsGenerator(maxDesired);
 while (sIter.hasNext()) {
    String aStr = (String) sIter.next();
    //do something with aStr
 }
</pre><br />

 * @author dickey
 */
public class RandomIPAddresses implements Iterator {
	
	private int limit;
	
	private Random rgen;
	
	public RandomIPAddresses(int limit) {
		if (limit <= 0) {
			throw new IllegalArgumentException("limit must be >0");
		}
		this.limit = limit;
		rgen = new Random(this.limit); //seed so that the same series is generated
	}

	/* 
	 * @see java.util.Iterator#remove()
	 */
	public void remove() {
		throw new UnsupportedOperationException("remove is not supported");
	}

	/* 
	 * @see java.util.Iterator#hasNext()
	 */
	public boolean hasNext() {
		assert limit >= 0;
		return limit > 0;
	}

	/* 
	 * @see java.util.Iterator#next()
	 */
	public Object next() {
		this.limit--;
		assert limit >= 0;
		StringBuffer ipStr = new StringBuffer(16);
		for (int i = 1; i <=4; i++) {
			ipStr.append(rgen.nextInt(256));
			if (i < 4) {
				ipStr.append('.');
			}
		}
		//System.out.println(ipStr);
		return ipStr.toString();
	}

}