processing4/processing/app/PdeUpdater.java

import java.io.*;
import java.net.*;
import java.util.*;


public class PdeUpdater {
  PdeUpdater() {
    Properties properties = new Properties();
    try {
      properties.load(new FileInputStream("lib/pde.properties"));
    } catch (Exception e) {
      System.err.println("Error reading pde.properties");
      e.printStackTrace();
      System.exit(1);
    }

    // 'enabled' no longer valid because 
    // this is a separate updater application
    boolean updateEnabled = true;
    //(new Boolean(properties.getProperty("update.enabled", 
    //				  "false"))).booleanValue();

    // check for updates from the server, if enabled
    //if (getBoolean("update.enabled", false)) {
    if (updateEnabled) {
      // open the update file to get the latest version
      long lastUpdate = 0;
      try {
	DataInputStream dis = 
	  new DataInputStream(new FileInputStream("lib/version"));
	lastUpdate = dis.readLong();
	//System.out.println("pde.jar timestamp is " + lastUpdate);
      } catch (IOException e) { }

      //String baseUrl = get("update.url");
      String baseUrl = properties.getProperty("update.url");

      try {
	URL url = new URL(baseUrl + "version");
	URLConnection conn = url.openConnection();
	//conn.connect();

	//System.out.println("date of last update" + conn.getDate());
	long newDate = conn.getLastModified();
	//System.out.println("server timestamp is " + newDate);
	//System.out.println((newDate - lastUpdate) + "ms newer");
	if (newDate > lastUpdate) {
	  System.out.println("new update available");

	  DataOutputStream vos = 
	    new DataOutputStream(new FileOutputStream("lib/version"));
	    //new DataOutputStream(new FileOutputStream("lib/version.update"));
	  vos.writeLong(newDate);
	  vos.flush();
	  vos.close();

	  url = new URL(baseUrl + "pde.jar");
	  conn = url.openConnection();

	  // move the old pde.jar file out of the way
	  //File pdeJar = new File("lib/pde.jar");
	  //pdeJar.renameTo("lib/pde.old.jar");

	  // download the new pde.jar file
	  //FileOutputStream os = new FileOutputStream("lib/pde.jar.update");
	  FileOutputStream os = new FileOutputStream("lib/pde.jar");
	  //Object object = conn.getContent();
	  //System.out.println(object);
	  InputStream is = conn.getInputStream();
	  copyStream(is, os);
	  os.close();

	  // if everything copied ok, rename new/old files
	  // this probably needs to be way more bulletproof
	  /*
	  File file = new File("lib/version");
	  if (file.exists()) 
	    System.out.println(file.renameTo(new File("lib/version.old")));
	  file = new File("lib/version.update");
	  System.out.println(file.renameTo(new File("lib/version")));

	  file = new File("lib/pde.jar");
	  file.delete();
	  //System.out.println(file.renameTo(new File("lib/pde.jar.old")));
	  file = new File("lib/pde.jar.update");
	  System.out.println(file.renameTo(new File("lib/pde.jar")));
	  */

	  // restart or relaunch
	  //System.out.println("done copying new version, restart");
	  //System.exit(0);

	}

	/*
	  try {
	    Class c = Class.forName("PdeApplication");
	    Object o = c.newInstance();
	  //PdeApplication.main(null);
	  } catch (Exception e) {
	    System.err.println("update failed");
	    e.printStackTrace();
	  }
	*/
	// mac mrj is not smart enough to exit the applicaiton here
	System.exit(0);

      } catch (IOException e1) {
	e1.printStackTrace();

	//} catch (MalformedURLException e2) {
	//e2.printStackTrace();
      }
    }
  }


  static public void copyStream(InputStream input, OutputStream output
				/*int padding, long length*/) 
    throws IOException {
    byte[] buffer = new byte[4096];
    int count;
    int amount;

    int length = Integer.MAX_VALUE;
    // if length is not actually known, the function will still break
    // in the correct spot, so just set to some enormous value
    //if (length == -1) {
    //length = Integer.MAX_VALUE;
    //}
    //if (padding != 0) {
    //input.skip((int) padding);
    //}

    while (true) {
      amount = (length < 4096) ? (int) length : 4096;
      //System.err.print(amount + " ");
      count = input.read(buffer, 0, amount);
      //System.out.println("got " + count);
      if (count == -1)
	break;

      output.write(buffer, 0, count);
      length -= count;	// used to be amount... bug?
      if (length == 0)
	break;
    }
    output.flush();
  }


  static public void main(String args[]) {
    new PdeUpdater();
  }
}