Help needed

For my degree project I am trying to write a simple messaging system for the shift I supervise at work to communicate outside of work across the internet. It will display a shift rota for the day and also they can send messages to each other, asynchronously. However i am failing miserably to code it. It is suppose to work on RMI

The message system has three classes, message, messageOperator, messageOperatorHolder and an interface MessageOperatorInterface
This is the code for message

An this is the code for messageOperator

import java.util.Enumeration;
import java.util.Hashtable;
import java.util.Map;
 
public class messageOperator implements messageOperatorServer {
 
public   Hashtable <Integer, message>MessOp = new Hashtable<Integer, message>();// stores messages for each messageOperator object.
 
public String password;
public Integer pinNumber;
public boolean Supervisor;
 
public messageOperator (String tempPassword, Integer tempPinNumber, boolean tempSupervisor){
 
password = tempPassword;
pinNumber = tempPinNumber;
Supervisor = tempSupervisor;
}
 
public Integer getPin(){
return (Integer) pinNumber;
}
 
public void removeMessage(Integer messageNo) {
 
MessOp.remove (messageNo); // uses HashTable method to remove the message
 
}

public void addMessage ( message mess) {
 
Integer A = mess.messageNumber();
MessOp.put ( A , mess ); // uses Hashtable method to add the messages
}
 
public int noOfMessages() {
 
return MessOp.size(); // uses Hashtable method to find number of messages
}
 
public static void getMessages(){
Enumeration e = MessOp.elements();
    while (e.hasMoreElements()){
    message tempMessage = (message) e.nextElement();
      System.out.println(tempMessage.text);
}
 
}

public  message getMessage ( Integer messageNo) {
 
return (message)MessOp.get(messageNo); // uses hashtable method to find message
}
 
public   void createMessage (messageOperator tempSender, messageOperator tempRecipient, String tempText ){
 message mess = new message ( tempSender, tempRecipient, tempText);
 
tempRecipient.addMessage(mess);
}
}

And then this is the messageOperatorHolder

import java.util.Hashtable;
import java.util.Map;
 
// holds messageOperator objects, and is registerd with rmi registry for access by client
// all methods to operate remoted are declared here. message and messageOperator basically variables
public class messageOperatorHolder implements messageOperatorHolderServer {
public   Hashtable <Integer, messageOperator>messOpHolder = new Hashtable<Integer, messageOperator>();// stores messageOperators
  public messageOperatorHolder () {
  }
 
  public void removeOperator ( Integer key) {
 
messOpHolder.remove (key); // uses Hashtable method to remove the operator day
 
}
 
public void addOperator (messageOperator mo) {
 
Integer B = mo.getPin();
messOpHolder.put( B, mo); // uses Hashtable method to add the operator
}
 
public messageOperator getOperator ( Integer key) {
return (messageOperator) messOpHolder.get(key);
 // uses Hashtable method to find operator
}

public void createOperator (String tempPassword, Integer tempPinNumber, boolean tempSupervisor){
messageOperator C = new messageOperator(tempPassword ,tempPinNumber , tempSupervisor);
addOperator( C );
}

public Integer getPin(){// gets messageOperator Pin
return (Integer) messageOperator.getPin();
}
 
public void removeMessage(Integer messageNo) {
 
messageOperator.remove (messageNo); // uses messageOperator method to remove the message
 
}

public void addMessage ( message mess) {

messageOperator.addMessage ( mess ); // uses messageOperator method to add the messages
}
 
public int noOfMessages() {
 
return messageOperator.noOfMessages(); // uses messageOperator method to find number of messages
}
 
public void getMessages(){
messageOperator.getMessages();
}

public message getMessage ( Integer messageNo) {
 
return (message)messageOperator.getMessage(messageNo); // uses messageOperator method to find message
}
 
public void createMessage (messageOperator tempSender, messageOperator tempRecipient, String tempText ){
 messageOperator.createMessage ( tempSender, tempRecipient, tempText);
 
}
 
}

When I compile it I get cannot use non-static method to reference static context.

I know this means that I am referencing the class messageOperator rather than an instance. But I need a system that will allow me to create messageOperators.

A little help? will need help the server in future if any one has got the time?

Regards
Al

Originally posted by Al Dodd:
When I compile it I get cannot use non-static method to reference static context.

More of a beginner's question if you are getting THAT error message.

Why are you using HashTable and Enumeration rather than more modern classes?
Why have you got a void getMessages() method?
Why are you not calling your classes by the correct names starting with a Capital Letter? Then you would realise that you are calling instance methods on the name of their type (the class name) rather than on the name of an object.

Just to reinforce what Campbell Ritchie said, check out number 10 of Top Ten Errors Java Programmers Make
Just ignore number 6 as it's completely wrong

(the author of the faq never read Pass-by-Value Please
[ June 03, 2008: Message edited by: Eric Weinberg ]

Okay I take on board the comment on coding convention and will change it and I am sorry for posting in the wrong forum!

What modern class would you suggest I use?

I already new why I was getting the non-static error but thanks for pointing out the FAQs, One of them answered another question I had.
Regards
Al

Modern classes? HashMap and Iterator.
And declare your Map like this:-

private Map<Integer, Message> messOp;
. . .
messOp = new HashMap<Integer, Message>();

Don't make the Map public.

If you are using integer numbers as keys for messages, why don't you use a List and use get(int) to get the message?

[edit]I have worked out why you aren't using a List.[/edit]
[ June 03, 2008: Message edited by: Campbell Ritchie ]