throw new IllegalWriteException("IMAP body parts are read-only");
    }


	/******************************************************************
	 * Following is a set of methods that deal with headers
	 * These methods are just overrides on the superclass methods to
     * allow lazy loading of the header information.
	 ********************************************************************/

	public String[] getHeader(String name) throws MessagingException {
        loadHeaders();
		return headers.getHeader(name);
	}

	public String getHeader(String name, String delimiter) throws MessagingException {
        loadHeaders();
		return headers.getHeader(name, delimiter);
	}

	public Enumeration getAllHeaders() throws MessagingException {
        loadHeaders();
		return headers.getAllHeaders();
	}

	public Enumeration getMatchingHeaders(String[] names)  throws MessagingException {
        loadHeaders();
		return headers.getMatchingHeaders(names);
	}

	public Enumeration getNonMatchingHeaders(String[] names) throws MessagingException {
        loadHeaders();
		return headers.getNonMatchingHeaders(names);
	}

	public Enumeration getAllHeaderLines() throws MessagingException {
        loadHeaders();
		return headers.getAllHeaderLines();
	}

	public Enumeration getMatchingHeaderLines(String[] names) throws MessagingException {
        loadHeaders();
		return headers.getMatchingHeaderLines(names);
	}

	public Enumeration getNonMatchingHeaderLines(String[] names) throws MessagingException {
        loadHeaders();
		return headers.getNonMatchingHeaderLines(names);
	}

    // the following are overrides for header modification methods.  These messages are read only,
    // so the headers cannot be modified.
    public void addHeader(String name, String value) throws MessagingException {
        throw new IllegalWriteException("IMAP messages are read-only");
    }

    public void setHeader(String name, String value) throws MessagingException {
        throw new IllegalWriteException("IMAP messages are read-only");
    }


    public void removeHeader(String name) throws MessagingException {
        throw new IllegalWriteException("IMAP messages are read-only");
    }

    public void addHeaderLine(String line) throws MessagingException {
        throw new IllegalWriteException("IMAP messages are read-only");
    }

        return super.getContentStream();
    }

    /***************************************************************************
     * Following is a set of methods that deal with headers These methods are
     * just overrides on the superclass methods to allow lazy loading of the
     * header information.
     **************************************************************************/

    public String[] getHeader(String name) throws MessagingException {
        loadHeaders();
        return headers.getHeader(name);
    }

    public String getHeader(String name, String delimiter) throws MessagingException {
        loadHeaders();
        return headers.getHeader(name, delimiter);
    }

    public Enumeration getAllHeaders() throws MessagingException {
        loadHeaders();
        return headers.getAllHeaders();
    }

    public Enumeration getMatchingHeaders(String[] names) throws MessagingException {
        loadHeaders();
        return headers.getMatchingHeaders(names);
    }

    public Enumeration getNonMatchingHeaders(String[] names) throws MessagingException {
        loadHeaders();
        return headers.getNonMatchingHeaders(names);
    }

    public Enumeration getAllHeaderLines() throws MessagingException {
        loadHeaders();
        return headers.getAllHeaderLines();
    }

    public Enumeration getMatchingHeaderLines(String[] names) throws MessagingException {
        loadHeaders();
        return headers.getMatchingHeaderLines(names);
    }

    public Enumeration getNonMatchingHeaderLines(String[] names) throws MessagingException {
        loadHeaders();
        return headers.getNonMatchingHeaderLines(names);
    }

    // the following are overrides for header modification methods. These
    // messages are read only,
    // so the headers cannot be modified.
    public void addHeader(String name, String value) throws MessagingException {
        throw new IllegalWriteException("NNTP messages are read-only");

                int socketFactoryPort = props.getIntProperty(MAIL_FACTORY_PORT, -1);

                // we choose the port used by the socket based on overrides.
                Integer portArg = new Integer(socketFactoryPort == -1 ? serverPort : socketFactoryPort);

                // use the current context loader to resolve this.
                ClassLoader loader = Thread.currentThread().getContextClassLoader();
                Class factoryClass = loader.loadClass(socketFactory);

                // done indirectly, we need to invoke the method using reflection.
                // This retrieves a factory instance.
                Method getDefault = factoryClass.getMethod("getDefault", new Class[0]);
                Object defFactory = getDefault.invoke(new Object(), new Object[0]);

                // now that we have the factory, there are two different createSocket() calls we use,
                // depending on whether we have a localAddress override.

                if (localAddress != null) {
                    // retrieve the createSocket(String, int, InetAddress, int) method.
                    Class[] createSocketSig = new Class[] { String.class, Integer.TYPE, InetAddress.class, Integer.TYPE };
                    Method createSocket = factoryClass.getMethod("createSocket", createSocketSig);

                    Object[] createSocketArgs = new Object[] { serverHost, portArg, localAddress, new Integer(localPort) };
                    socket = (Socket)createSocket.invoke(defFactory, createSocketArgs);

    }


    /**
     * Manage the initial connection to the POP3 server.  This is the first 
     * point where we obtain the information needed to make an actual server 
     * connection.  Like the Store protocolConnect method, we return false 
     * if there's any sort of authentication difficulties. 
     * 
     * @param host     The host of the mail server.
     * @param port     The mail server connection port.
     * @param user     The connection user name.
     * @param password The connection password.
     * 
     * @return True if we were able to connect and authenticate correctly. 
     * @exception MessagingException
     */
    public synchronized boolean protocolConnect(String host, int port, String username, String password) throws MessagingException {
        // NOTE:  We don't check for the username/password being null at this point.  It's possible that 
        // the server will send back a PREAUTH response, which means we don't need to go through login 
        // processing.  We'll need to check the capabilities response after we make the connection to decide 
        // if logging in is necesssary. 
        
        // save this for subsequent connections.  All pool connections will use this info.
        // if the port is defaulted, then see if we have something configured in the session.
        // if not configured, we just use the default default.
        if (port == -1) {
            // check for a property and fall back on the default if it's not set.
            port = props.getIntProperty(MAIL_PORT, props.getDefaultPort());
            // it's possible that -1 might have been explicitly set, so one last check. 
            if (port == -1) {
                port = props.getDefaultPort(); 
            }
        }
    	
    	// Before we do anything, let's make sure that we succesfully received a host
    	if ( host == null ) {
    		host = DEFAULT_MAIL_HOST;
    	}
        
        this.host = host;
        this.port = port;
        this.username = username;
        this.password = password;
        
        // make sure we have the realm information 
        realm = props.getProperty(MAIL_SASL_REALM); 
        // get an authzid value, if we have one.  The default is to use the username.
        authid = props.getProperty(MAIL_AUTHORIZATIONID, username);