Got it working with JSP

Hi,

I put some effort into making it work with websites based on JSP. (I hope it's not against the terms of service)

implement this class:

/*
 * Created on Dec 18, 2004
 */
package coop.techunity.de;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import java.util.Vector;

/**
 * @author Thomas Lange www.techunity.de
 */
public class CoOp {
	private static Vector ads = new Vector();
	private static long lastAd = 0;

	/**
	 * Get one ad from remote ad server
	 * @return
	 */
	private static String getAd() {
		String url = "http://ads.digitalpoint.com/network.php?s=www.yourdomainDOTcom&type=link";
		URL urlURL;
		try {
			urlURL = new URL(url);
		} catch (MalformedURLException e1) {
			System.out.println("Malformatted url");
			e1.printStackTrace();
			return null;
		}
		try {
			URLConnection urlConnection = urlURL.openConnection();
			BufferedReader in = new BufferedReader(
					new InputStreamReader( urlConnection.getInputStream()));
			String line = null;
			String firstline = null;
			while ((line = in.readLine()) != null) {
				if (firstline == null) {
					firstline = line;
				}
			}
			in.close();
			return firstline;
		} catch (IOException e2) {
			System.out.println("Couldn't read / send urlconnection failure");
			e2.printStackTrace();
			return null;
		}
	}

	/**
	 * get an ad to display (utilizes cache)
	 * @return next ad as String or "" if an error occured
	 */
	public static String nextAd() {
		// Less than 400 ads in cache or last update more than 900 ms ago?
		if (ads.size() < 400 || lastAd + 900 < System.currentTimeMillis()) {
			// Yes, get an additional new ad from the network.
			String ad = getAd();
			lastAd = System.currentTimeMillis();
			if (ad != null) {
				ads.add(ad);
				synchronized (ads) {
					if (ads.size() > 400) {
						// Remove oldest ad from cache, if more than 400.
						ads.remove(0);
					}
				}
				return ad;
			}
			return "";
		}
		else {
			// we've got enough ads in the cache already.
			// return a random one.
			synchronized (ads) {
				return (String) ads.get((int)(Math.random() * ads.size()));
			}
		}
	}

}

Code (markup):

and use it in your jsp pages with

<%=de.techunity.coop.CoOp.nextAd()>

or implement a custom tag.

Cheers
Thomas