import?java.io.*;
import?java.rmi.*;
import?java.util.*;

/**
?*?class?Client?represents?a?client?for?the?SSD8?Distributed?Message
?*?Center.
?*
?*?@author?wben
?*?@version?1.0
?*
?*/
public?class?Client?{

	/**
	?*?main?method
	?*/
	public?static?void?main（String[]?args）?{

		int?portNumber?=?1099;
		String?hostname?=?“localhost“;

		BufferedReader?keyboard?=?new?BufferedReader（new?InputStreamReader（System.in））;

		/**
		?*?Print?usage?instructions?if?the?incorrect?paramteres?are?supplied.
		?*/
		
		int?choice?=?0;
		String?username?password?recipientname?message;

		/**
		?*?Create?the?connection?to?the?message?center.
		?*/
		MessageInterface?mc?=?null;

		try?{
			mc?=?（MessageInterface）?Naming.lookup（“rmi://“?+?hostname?+?“:1099“??+?“/Message“）;
		}?catch?（Exception?e）?{
			e.printStackTrace（）;
		}

		/**
		?*?Loop?forever?while?displaying?the?menu?and?performing?operations?for
		?*?the?user.
		?*/
		while?（true）?{

			System.out.println（“**********?Distributed?Message?Center?**********?“）;
			System.out.println（“（1）?Show?registered?users?“）;
			System.out.println（“（2）?Register?a?new?user“）;
			System.out.println（“（3）?Check?Messages“）;
			System.out.println（“（4）?Leave?a?message“）;
			System.out.println（“（5）?Exit“）;
			System.out.println（“************************************************“）;
			System.out.println（“Enter?choice:?“）;
			try?{
				choice?=?Integer.parseInt（keyboard.readLine（））;
			}?catch?（IOException?e）?{
				e.printStackTrace（）;
			}

			if?（choice?==?1）?{
				try?{
					String?sr?=?null;
					sr?=mc.showusers（）;
					System.out.println（sr）;
					
				}?catch?（Exception?e）?{
					e.printStackTrace（）;
				}
			}

			if?（choice?==?2）?{
				try?{
					System.out.println（“Enter?username:?“）;
					username?=?keyboard.readLine（）;
					System.out.println（“Enter?password:?“）;
					password?=?keyboard.readLine（）;
					if?（!mc.register（username?password））?{
						System.out.println（“Registration?failed?try?another?username!“）;
					}?else?{
						System.out.println（“Registration?succeeded!“）;
					}
				}?catch?（Exception?e）?{
					e.printStackTrace（）;
				}
			}

			if?（choice?==?3）?{
				try?{
					System.out.println（“Enter?username:?“）;
					username?=?keyboard.readLine（）;
					System.out.println（“Enter?password:?“）;
					password?=?keyboard.readLine（）;
					Vector?messages?=?mc.checkmessages（username?password）;
					if?（messages?==?null）?{
						System.out.println（“Authentication?failed?or?you?have?no?messages!“）;
					}?else?{
						System.out.println（“Your?messages:?“）;
						for?（int?i?=?0;?i?							System.out.println（（Message）?messages.get（i））;
						}
					}
				}?catch?（Exception?e）?{
					e.printStackTrace（）;
				}
			}

			if?（choice?==?4）?{
				try?{
					System.out.println（“Enter?your?username:?“）;
					username?=?keyboard.readLine（）;
					System.out.println（“Enter?your?pa

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----
?????目錄???????????0??2019-12-28?17:32??Exam2\
?????文件?????????302??2019-12-28?15:25??Exam2\.classpath
?????文件?????????379??2019-12-28?15:25??Exam2\.project
?????目錄???????????0??2019-12-28?17:32??Exam2\.settings\
?????文件?????????598??2019-12-28?15:25??Exam2\.settings\org.eclipse.jdt.core.prefs
?????目錄???????????0??2019-12-28?17:32??Exam2\bin\
?????文件????????3665??2019-12-28?17:28??Exam2\bin\Client.class
?????文件????????2051??2019-12-28?15:28??Exam2\bin\Message.class
?????文件????????3120??2019-12-28?17:31??Exam2\bin\MessageCenter.class
?????文件?????????507??2019-12-28?17:26??Exam2\bin\MessageInterface.class
?????文件????????1140??2019-12-28?15:59??Exam2\bin\RMIServer.class
?????文件????????1095??2019-12-28?16:54??Exam2\bin\User.class
?????目錄???????????0??2019-12-28?17:32??Exam2\src\
?????文件????????3504??2019-12-28?17:28??Exam2\src\Client.java
?????文件????????1953??2019-12-28?15:28??Exam2\src\Message.java
?????文件????????3128??2019-12-28?17:31??Exam2\src\MessageCenter.java
?????文件?????????913??2019-12-28?17:26??Exam2\src\MessageInterface.java
?????文件?????????651??2019-12-28?15:59??Exam2\src\RMIServer.java
?????文件?????????988??2019-12-28?16:54??Exam2\src\User.java