client.java

SSD8-exam2,这是我的答案

import java.rmi.*;
import java.io.*;
import javax.naming.*;
/**
 * Class Client implentents menu model.
 * 
 * @version 1.0  9 June 2007 
 * @author Zhao Xiaoyu
 */
public class Client{
	
	/** 
	 *  Define a general variable to mark the error state
	 *  and according to the error state to return 
	 *  corresponding hint message. 
	 */
	private static int flag = 0;
	
	public static void main(String[] args){
		Client c = new Client();
		c.run(args);
	}
	
	/**
	 *	Implement the client-end menu for user to select. 
	 */
	void run(String[] args){
		try{
			/**
			 * This interface represents a naming context, which consists of a
			 * set of name-to-object bindings.
			 */
			Context nc = new InitialContext();

			/** Declare a RMIIntf object and assign it to null */
			RMIIntf r1 = null;

			// If the parameter number is not enough exit the program.
			if (args.length != 2) {
				System.out
						.println("\nYou must input remote host ip address and port number!");
				System.exit(0);
			}
			try {
				// Retrieves the named object.
				r1 = (RMIIntf) nc.lookup("rmi://" + args[0] + ":" + args[1]
						+ "/RemoteService");
			} catch (NumberFormatException nfe) {
				System.out.println("\nInput Parameter Format Error!");
				System.exit(0);
			}
			
			BufferedReader rd = new BufferedReader(new InputStreamReader(
					System.in));

			/** Loop to display the main menu. */
			while (true) {
				// Display the menu item and hint for input.
				System.out
						.println("1.User Register.\n2.Show Users.\n3.Check Message.\n4.Leave Message.\n5.User Exit");
				System.out.print("Please Input Your choice > ");

				/** Read in choice. */
				String choice = rd.readLine();
				/** Declare the function parameters used below. */
				String u, p, r, mt;

				if (isCorrectNumber(choice)) {

					// Parse the choice to int.
					int c = Integer.parseInt(choice);

					// According to user's choice enter different branchs
					switch (c) {
					
						case 1:
							System.out.print("Please Input username >> ");
							u = rd.readLine();
							while(u.equals("")){
								System.out.println("Username Can't be null, Please Input Again!");
								System.out.print("Please Input username >> ");
								u = rd.readLine();
								
							}
							System.out.print("Please Input password >> ");
							p = rd.readLine();
							while(p.equals("")){
								System.out.println("Password Can't be null, Please Input Again!");
								System.out.print("Please Input password >> ");
								p = rd.readLine();	
							}
							System.out.println(r1.register(u, p));
							break;
							
						case 2:	
							System.out.println(r1.showusers());
							break;
							
						case 3:
							System.out.print("Please Input username >> ");
							u = rd.readLine();
							while(u.equals("")){
								System.out.println("Username Can't be null, Please Input Again!");
								System.out.print("Please Input username >> ");
								u = rd.readLine();	
							}
							System.out.print("Please Input password >> ");
							p = rd.readLine();
							while(p.equals("")){
								System.out.println("Password Can't be null, Please Input Again!");
								System.out.print("Please Input password >> ");
								p = rd.readLine();	
							}
							System.out.println(r1.checkmessages(u,p));
							break;
							
						case 4:	
							System.out.print("Please Input Username >> ");
							u = rd.readLine();
							while(u.equals("")){
								System.out.println("Username Can't be null, Please Input Again!");
								System.out.print("Please Input username >> ");
								u = rd.readLine();	
							}
							System.out.print("Please Input Receiver name >> ");
							r = rd.readLine();
							while(r.equals("")){
								System.out.println("Receivername Can't be null, Please Input Again!");
								System.out.print("Please Input Receiver name >> ");
								r = rd.readLine();	
							}
							System.out.print("Please Input Message-Text >> ");
							mt = rd.readLine();
							while(mt.equals("")){
								System.out.println("You shouldn't send empty message, Please Input Again!");
								System.out.print("Please Input Message-Text >> ");
								mt = rd.readLine();	
							} 
							System.out.println(r1.leavemessage(u,r,mt));
							break;
							
						case 5:
							System.out.println("You exit the program successfully!");
							System.exit(0);
					}
				}else {
					//	Return a variety of error messages.
					if (flag == 1)
						System.out
								.println("\nYou choice must between 1~5!\n");
					if (flag == 2)
						System.out.println("\nYou must input a number!\n");
					continue;
				}
			}	
					
		}catch (RemoteException re) {
			System.out.println(re);
		} catch (Exception e) {
			System.out.println(e);
		}	
	}
	/** Implement the functionality of count logic value
	 * 
	 *	@para choice the choice express the user's selecttion 
	 *	@return return the judged logic value  
	 */
	public static boolean isCorrectNumber(String choice) {

		// Judge whether is input choice'length is longer than one character. 
		if (choice.length() == 1) {
			//	Judge whether the input string can be parse into digit.
			if (Character.isDigit(choice.charAt(0))) {
				int c = Integer.parseInt(choice);
				//	Judge whether the choice is between the menu option.
				if (c > 0 && c < 6)
					return true;
				else{
					flag = 1;
					return false;
				}		
			} else{
				flag = 2;
				return false;
			}
				
		} else {
			/**
			 * 	According to whether the input choice is digit 
			 * 	return different error flag.
			 */
			int i = 0;
			for (; i < choice.length(); i++) {
				if (!Character.isDigit(choice.charAt(i)))
					break;
			}
			if (i == choice.length())
				flag = 1;
			else
				flag = 2;
			return false;
		}

	}
	
}