/* Daniel Shiffman               */
/* Programming from A to Z       */
/* Spring 2006                   */
/* http://www.shiffman.net       */
/* daniel.shiffman@nyu.edu       */

// A Simple Thread example
// Reads information from an XML feed every so often
// occuring to the "wait" variable

import java.util.ArrayList;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import a2z.*;                  // Lookie, our code is a Processing library!

public class NewsThread extends Thread {

  private boolean running;           // Is the thread running?  Yes or no?
  private int wait;                  // How many milliseconds should we wait in between executions?
  private ArrayList headlines;       // ArrayList that will hold the news headlines
  private boolean available;         // Is new news available?

  // Constructor, create the thread
  // It is not running by default
  public NewsThread (int w, int total){
    wait = w;
    running = false;
    available = false;
    headlines = new ArrayList();
  }

  // Overriding "start()"
  public void start ()
  {
    // Set running equal to true
    running = true;
    // Print messages
    System.out.println("Starting thread (will execute every " + (wait/1000) + " seconds.)"); 
    // Do whatever start does in Thread, don't forget this!
    super.start();
  }


  // We must implement run, this gets triggered by start()
  public void run ()
  {
    while (running){
      System.out.println("reloading. . ."); 
      check();
      // Ok, let's wait for however long we should wait
      try {
        sleep((long)(wait));
      } 
      catch (Exception e) {
      }
    }
  }


  // Our method that quits the thread
  public void quit()
  {
    System.out.println("Quitting."); 
    running = false;  // Setting running to false ends the loop in run()
    // We used to need to call super.stop()
    // We don't any more since it is deprecated, see: http://java.sun.com/j2se/1.5.0/docs/guide/misc/threadPrimitiveDeprecation.html
    // super.stop();
    // Instead, we use interrupt, in case the thread is waiting. . .
    super.interrupt();
  }

  public boolean available() {
    return available;
  }
  public synchronized ArrayList getHeadlines() {
    // We should put a while (!available) loop here
    // but since we are explicitly only calling this function if available is true, we're ok
    available = false;
    notifyAll(); // let's notify everyone that available has changed
    return headlines;     
  }

  private synchronized void check() {
    headlines = new ArrayList();
    // Create a URL object and open an InputStream
    A2ZXmlReader xmlreader = null;
    try {
      xmlreader = new A2ZXmlReader("http://itp.nyu.edu/icm/proxy/proxy.php?url=http://news.google.com/?output=rss");
      // Call our recursive search function to locate the element we want

      ArrayList elements = new ArrayList();
      xmlreader.fillArrayList(xmlreader.getRoot(),"title",elements);
      for (int i = 0; i < elements.size(); i++) {
        Element e = (Element) elements.get(i);
        // As long as we find the element
        if (e != null) {
          Node n = e.getFirstChild();
          String headline = n.getNodeValue();
          headline = headline.replaceAll("&#39;","'");
          if ((!headline.matches("Google News")) && (headlines.size() < maxheadlines))  {
            headlines.add(headline);
          }
        }
      }
      available = true;
      notifyAll();  // let's notify everyone that the headlines have been updated
    } 
    catch (Exception e) {
      System.out.println("Something went wrong. " + e);
    }
  }
}