package com.enterprisemath.articles.unitperformance;

/**
 * Provider for user related data.
 * 
 * @author radek.hecl
 */
public interface UserProvider {

 /**
  * Returns user name.
  * 
  * @param userId user id
  * @return user name
  */
 public String getUserName(String userId);

}

// -----------------------------------------------------

package com.enterprisemath.articles.unitperformance;

import java.util.Date;

/**
 * Service for message broadcast.
 * 
 * @author radek.hecl
 */
public interface BroadcastService {

 /**
  * Broadcasts message.
  * 
  * @param userName user name
  * @param timestamp timestamp
  * @param message message
  */
 public void broadcastMessage(String userName, Date timestamp, String message);

}

// -----------------------------------------------------

package com.enterprisemath.articles.unitperformance;

import com.enterprisemath.utils.Dates;
import com.enterprisemath.utils.ValidationUtils;
import java.util.Date;
import org.apache.commons.lang3.builder.ToStringBuilder;

/**
 * Module for message broadcasting.
 *
 * @author radek.hecl
 */
public class MessageBroadcastModule {

 /**
  * Provider for user data.
  */
 private UserProvider userProvider;

 /**
  * Service for broadcast.
  */
 private BroadcastService broadcastService;

 /**
  * Creates new instance.
  */
 private MessageBroadcastModule() {}

 /**
  * Guards this object to be consistent. Throws exception if this is not the case.
  */
 private void guardInvariants() {
  ValidationUtils.guardNotNull(userProvider, "userProvider cannot be null");
  ValidationUtils.guardNotNull(broadcastService, "broadcastService cannot be null");
 }

 /**
  * Processes message.
  *
  * @param message message
  */
 public void processMessage(String message) {
  String[] parts = message.split("\\|");
  String userName = null;
  String txt = null;
  Date now = null;
  for (String part: parts) {
   String[] subs = part.split("=", 2);
   if (subs[0].equals("userId")) {
    userName = userProvider.getUserName(subs[1]);
   }
   else if (subs[0].equals("timestamp")) {
    now = Dates.parse(subs[1], "yyyy/MM/dd HH:mm:ss");
   }
   else if (subs[0].equals("message")) {
    txt = subs[1];
   }
  }

  ValidationUtils.guardNotNull(userName, "wrong input message, user is missing");
  ValidationUtils.guardNotNull(txt, "wrong input message, text is missing");
  ValidationUtils.guardNotNull(now, "wrong input message, timestamp is missing");
  broadcastService.broadcastMessage(userName, now, txt);

 }

 @Override
 public String toString() {
  return ToStringBuilder.reflectionToString(this);
 }

 /**
  * Creates new instance.
  *
  * @param userProvider provider for user data
  * @param broadcastService broadcast service
  * @return created object
  */
 public static MessageBroadcastModule create(UserProvider userProvider, BroadcastService broadcastService) {
  MessageBroadcastModule res = new MessageBroadcastModule();
  res.userProvider = userProvider;
  res.broadcastService = broadcastService;
  res.guardInvariants();
  return res;
 }

}