messagecenterserver.java

卡耐基梅陇大学SSD8全部练习和考试完全答案

import java.io.*;
import java.util.*;
import java.text.*;

import org.omg.CORBA.Context;
import org.omg.CORBA.ContextList;
import org.omg.CORBA.DomainManager;
import org.omg.CORBA.ExceptionList;
import org.omg.CORBA.NVList;
import org.omg.CORBA.NamedValue;
import org.omg.CORBA.Object;
import org.omg.CORBA.Policy;
import org.omg.CORBA.Request;
import org.omg.CORBA.SetOverrideType;
import org.omg.CORBA.*;
import org.omg.CosNaming.*;
import org.omg.CosNaming.NamingContextPackage.*;

/**
 * Run the server to execute the distributed system.
 * @author jack
 *
 */
public class MessageCenterServer implements MessageCenter {

	/*store the name and password of users */
	private static HashMap<String, String> user = new HashMap<String, String>();
	
	/*store the message of every user*/
	private static ArrayList<MessageContent> messageList = new ArrayList<MessageContent>();
	
	/*store the date formate*/
	private static SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
	
	/**
	 * run the main method
	 * @param args
	 */
	public static void main(String args[]) {
		
		try{
		    // create and initialize the ORB
		    ORB orb = ORB.init(args, null);

		    // create servant and register it with the ORB
		    MessageCenterServer helloRef = new MessageCenterServer();
		    orb.connect(helloRef);

		    // get the root naming context
		    org.omg.CORBA.Object objRef = 
			orb.resolve_initial_references("NameService");
		    NamingContext ncRef = NamingContextHelper.narrow(objRef);

		    // bind the Object Reference in Naming
		    NameComponent nc = new NameComponent("MessageCenter", "");
		    NameComponent path[] = {nc};
		    ncRef.rebind(path, helloRef);

			System.out.println ("servant registered")
		    // wait for invocations from clients
	            while(true) {
	            	Thread.sleep(1000);
	            }

		} catch (Exception e) {
		    System.err.println("ERROR: " + e);
		    e.printStackTrace(System.out);
		}
	}
	/**
	 * this method should print each message that was left for the user.
	 * 
	 * @param userName the name of user
	 * @param password the password
	 */	
	public String register(String u,String p){
		if(!isUserExisted(u)){
			user.put(u, p);
			return "\nRegister Successfully!\n";
		}else 
			return "\nUsername Already Existed, Please select another!\n";
	}
	
	/** Implement the functionality of show users
	 * 
	 *	@return return a list of username or the error message.  
	 */
	public String showusers(){
		
		String returnList = "";
		if(!user.isEmpty()){
			Iterator i = user.keySet().iterator();
			returnList += "\nAll usernames are listing below :\n";
			while(i.hasNext()){
				returnList +=  (String)i.next() + "\n";
			}
			return returnList;
		}else 
			return "\nSorry, There is no user registered now!\n";
		
	}
	
	/** Implement the functionality of check message.
	 * 
	 *	@para u the u express the usersname 
	 *	@para p the p express the password
	 *	@return return the error hint or alist of message.  
	 */
	public String checkmessages(String u, String p){
		int index = 0;
		String returnMessage = "";
		if(isUserExisted(u)){
			if(canLogin(u, p)){
				if(!isUserHasNoMessage(u)){
					Iterator i = messageList.iterator();
					returnMessage +="\nYour messages are listing below :\n";
					
					while(i.hasNext()){
						MessageContent m = (MessageContent)i.next();
						if(m.getReceiver().equals(u)){
							index++;
							returnMessage += "Mail " + index + " :";
							returnMessage += m.toString();
						}
					} 
				}else 
					return "\nSorry, There is no message for you!\n";	
			}else 
				return "\nYour Password Wrong, Input again!\n";
		}else{
			return "\nYou haven't registered yet, Please register first\n";
		}
		return returnMessage;
	}
	
	/** Implement the functionality of leave message.
	 * 
	 *	@para u the u express the usersname 
	 *	@para r the r express the receiver names.
	 *	@para mt the mt express the message content
	 *	@return return the error message.  
	 */
	public String leavemessage(String u, String r, String mt){
		String sendDate = "";
		
		if(isUserExisted(u)){
			if(!u.equals(r)){
				Date now = new Date();
				sendDate = sdf.format(now);
				MessageContent mc = new MessageContent(u, r, sendDate, mt);
				messageList.add( mc ); 
				return "\nLeave message successfully!\n";
			}else 
				return "\nYou shouldn't send message to yourself\n";	
		}else 
			return "\nLogin failed!\n";
	}
	
	/** Implement the functionality of count logic value.
	 * 
	 *	@para u the u express the usersname 
	 *	@return return a boolean to express whether there
	 *	 there is no message for the user.  
	 */
	public boolean isUserHasNoMessage(String u){
		Iterator i = messageList.iterator();
		while(i.hasNext()){
			if(((MessageContent)i.next()).getReceiver().equals(u))
				return false;
		}
		return true;
	}
	
	/** Implement the functionality of count logic value.
	 * 
	 *	@para u the u express the usersname 
	 *	@para p the p express the password
	 *	@return return a boolean to judge whether the user can login.  
	 */
	public boolean canLogin(String u, String p){	
		if(isUserExisted(u)){
			if(user.get(u).equals(p))
				return true;
		}
		return false;
	}
	
	/** Implement the functionality of count logic value.
	 * 
	 *	@para u the u express the usersname 
	 *	@return return a boolean to judge whether the username existed.  
	 */
	public boolean isUserExisted(String u){
		return user.containsKey(u);	
	}

	@Override
	public Request _create_request(Context ctx, String operation,
			NVList arg_list, NamedValue result) {
		// TODO Auto-generated method stub
		return null;
	}

	@Override
	public Request _create_request(Context ctx, String operation,
			NVList arg_list, NamedValue result, ExceptionList exclist,
			ContextList ctxlist) {
		// TODO Auto-generated method stub
		return null;
	}

	@Override
	public Object _duplicate() {
		// TODO Auto-generated method stub
		return null;
	}

	@Override
	public DomainManager[] _get_domain_managers() {
		// TODO Auto-generated method stub
		return null;
	}

	@Override
	public Object _get_interface_def() {
		// TODO Auto-generated method stub
		return null;
	}

	@Override
	public Policy _get_policy(int policy_type) {
		// TODO Auto-generated method stub
		return null;
	}

	@Override
	public int _hash(int maximum) {
		// TODO Auto-generated method stub
		return 0;
	}

	@Override
	public boolean _is_a(String repositoryIdentifier) {
		// TODO Auto-generated method stub
		return false;
	}

	@Override
	public boolean _is_equivalent(Object other) {
		// TODO Auto-generated method stub
		return false;
	}

	@Override
	public boolean _non_existent() {
		// TODO Auto-generated method stub
		return false;
	}

	@Override
	public void _release() {
		// TODO Auto-generated method stub

	}

	@Override
	public Request _request(String operation) {
		// TODO Auto-generated method stub
		return null;
	}

	@Override
	public Object _set_policy_override(Policy[] policies,
			SetOverrideType set_add) {
		// TODO Auto-generated method stub
		return null;
	}

}