/**
    * Logback: the reliable, generic, fast and flexible logging framework.
    * Copyright (C) 1999-2015, QOS.ch. All rights reserved.
    *
    * This program and the accompanying materials are dual-licensed under
    * either the terms of the Eclipse Public License v1.0 as published by
    * the Eclipse Foundation
    *
    *   or (per the licensee's choosing)
   *
   * under the terms of the GNU Lesser General Public License version 2.1
   * as published by the Free Software Foundation.
   */
  package chapters.mdc;
  
  import java.rmi.RemoteException;
  import java.rmi.registry.LocateRegistry;
  import java.rmi.registry.Registry;
  import java.rmi.server.UnicastRemoteObject;
  import java.util.Vector;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import org.slf4j.MDC;
  
  import ch.qos.logback.classic.LoggerContext;
  import ch.qos.logback.classic.joran.JoranConfigurator;
  import ch.qos.logback.core.joran.spi.JoranException;
  
  /**
   * A simple NumberCruncher implementation that logs its progress when
   * factoring numbers. The purpose of the whole exercise is to show the
   * use of mapped diagnostic contexts in order to distinguish the log
   * output from different client requests.
   * */
  public class NumberCruncherServer extends UnicastRemoteObject implements NumberCruncher {
  
      private static final long serialVersionUID = 1L;
  
      static Logger logger = LoggerFactory.getLogger(NumberCruncherServer.class);
  
      public NumberCruncherServer() throws RemoteException {
      }
  
      public int[] factor(int number) throws RemoteException {
          // The client's host is an important source of information.
          try {
              MDC.put("client", NumberCruncherServer.getClientHost());
          } catch (java.rmi.server.ServerNotActiveException e) {
              logger.warn("Caught unexpected ServerNotActiveException.", e);
          }
  
          // The information contained within the request is another source
          // of distinctive information. It might reveal the users name,
          // date of request, request ID etc. In servlet type environments,
          // useful information is contained in the HttpRequest or in the
          // HttpSession.
          MDC.put("number", String.valueOf(number));
  
          logger.info("Beginning to factor.");
  
          if (number <= 0) {
              throw new IllegalArgumentException(number + " is not a positive integer.");
          } else if (number == 1) {
              return new int[] { 1 };
          }
  
          Vector<Integer> factors = new Vector<Integer>();
          int n = number;
  
          for (int i = 2; (i <= n) && ((i * i) <= number); i++) {
              // It is bad practice to place log requests within tight loops.
              // It is done here to show interleaved log output from
              // different requests.
              logger.debug("Trying " + i + " as a factor.");
  
              if ((n % i) == 0) {
                  logger.info("Found factor " + i);
                  factors.addElement(i);
  
                  do {
                      n /= i;
                  } while ((n % i) == 0);
              }
  
              // Placing artificial delays in tight loops will also lead to
              // sub-optimal results. :-)
              delay(100);
          }
  
          if (n != 1) {
              logger.info("Found factor " + n);
              factors.addElement(n);
          }
  
          int len = factors.size();
  
          int[] result = new int[len];
  
         for (int i = 0; i < len; i++) {
             result[i] = ((Integer) factors.elementAt(i)).intValue();
         }
 
         // clean up
         MDC.remove("client");
         MDC.remove("number");
 
         return result;
     }
 
     static void usage(String msg) {
         System.err.println(msg);
         System.err.println("Usage: java chapters.mdc.NumberCruncherServer configFile\n" + "   where configFile is a logback configuration file.");
         System.exit(1);
     }
 
     public static void delay(int millis) {
         try {
             Thread.sleep(millis);
         } catch (InterruptedException e) {
         }
     }
 
     public static void main(String[] args) {
         if (args.length != 1) {
             usage("Wrong number of arguments.");
         }
 
         String configFile = args[0];
 
         if (configFile.endsWith(".xml")) {
             try {
                 LoggerContext lc = (LoggerContext) LoggerFactory.getILoggerFactory();
                 JoranConfigurator configurator = new JoranConfigurator();
                 configurator.setContext(lc);
                 lc.reset();
                 configurator.doConfigure(args[0]);
             } catch (JoranException je) {
                 je.printStackTrace();
             }
         }
 
         NumberCruncherServer ncs;
 
         try {
             ncs = new NumberCruncherServer();
             logger.info("Creating registry.");
 
             Registry registry = LocateRegistry.createRegistry(Registry.REGISTRY_PORT);
             registry.rebind("Factor", ncs);
             logger.info("NumberCruncherServer bound and ready.");
         } catch (Exception e) {
             logger.error("Could not bind NumberCruncherServer.", e);
 
             return;
         }
     }
 }