pop3folder.java

java 开发的一个电子邮局,挺实用的

/*
 * POP3Folder.java
 * Copyright (C) 1999 dog <[e-mail]>
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 * 
 * You may retrieve the latest version of this library from
 * http://www.dog.net.uk/knife/
 */

package dog.mail.pop3;

import java.io.*;
import java.util.*;
import javax.mail.*;
import javax.mail.event.*;

/**
 * The folder class implementing the POP3 mail protocol.
 *
 * @author [e-mail]
 * @version 1.1
 */
public class POP3Folder extends Folder {

	Hashtable messages = new Hashtable();
	boolean readonly = false, open = false;
	int type;

	Folder inbox;

	/**
	 * Constructor.
	 */
	protected POP3Folder(Store store, int type) {
		super(store);
		this.type = type;
	}

	/**
	 * Returns the name of this folder.
	 */
	public String getName() {
		switch (type) {
		  case HOLDS_FOLDERS:
			return "/";
		  case HOLDS_MESSAGES:
			return "INBOX";
		  default:
			return "(Unknown)";
		}
	}

	/**
	 * Returns the full name of this folder.
	 */
	public String getFullName() {
		return getName();
	}

	/**
	 * Returns the type of this folder.
	 * @exception MessagingException if a messaging error occurred
	 */
	public int getType() throws MessagingException {
		return type;
	}

	/**
	 * Indicates whether this folder exists.
	 * @exception MessagingException if a messaging error occurred
	 */
	public boolean exists() throws MessagingException {
		return (type==HOLDS_MESSAGES);
	}

	/**
	 * Indicates whether this folder contains new messages.
	 * @exception MessagingException if a messaging error occurred
	 */
	public boolean hasNewMessages() throws MessagingException {
		return getNewMessageCount()>0;
	}

	/**
	 * Opens this folder.
	 * @exception MessagingException if a messaging error occurred
	 */
	public void open(int mode) throws MessagingException {
		switch (mode) {
		  case READ_WRITE:
			readonly = false;
			break;
		  case READ_ONLY:
			readonly = true;
			break;
		}
		open = true;
		notifyConnectionListeners(ConnectionEvent.OPENED);
	}

	/**
	 * Closes this folder.
	 * @param expunge if the folder is to be expunged before it is closed
	 * @exception MessagingException if a messaging error occurred
	 */
	public void close(boolean expunge) throws MessagingException {
		if (!open)
			throw new MessagingException("Folder is not open");
		if (expunge)
			expunge();
		open = false;
		notifyConnectionListeners(ConnectionEvent.CLOSED);
	}

	/**
	 * Expunges this folder.
	 * This deletes all the messages marked as deleted.
	 * @exception MessagingException if a messaging error occurred
	 */
	public Message[] expunge() throws MessagingException {
		if (!open)
			throw new MessagingException("Folder is not open");
		if (readonly)
			throw new MessagingException("Folder was opened read-only");
        Vector vector = new Vector();
		for (Enumeration enum = messages.elements(); enum.hasMoreElements(); ) {
            Message message = (Message)enum.nextElement();
			Flags flags = message.getFlags();
			if (flags.contains(Flags.Flag.DELETED))
				vector.addElement(message);
		}
		Message[] delete = new Message[vector.size()]; vector.copyInto(delete);
		for (int i=0; i<delete.length; i++)
			((POP3Store)store).delete(delete[i].getMessageNumber());
        messages.clear();
		return delete;
	}

	/**
	 * Indicates whether this folder is open.
	 */
	public boolean isOpen() {
		return open;
	}

	/**
	 * Returns the permanent flags for this folder.
	 */
	public Flags getPermanentFlags() { return new Flags(); }
	
	/**
	 * Returns the number of messages in this folder.
	 * This results in a STAT call to the POP3 server, so the latest
	 * count is always delivered.
	 * @exception MessagingException if a messaging error occurred
	 */
	public int getMessageCount() throws MessagingException {
		return ((POP3Store)store).getMessageCount();
	}

	/**
	 * Returns the specified message number from this folder.
	 * The message is only retrieved once from the server.
	 * Subsequent getMessage() calls to the same message are cached.
	 * Since POP3 does not provide a mechanism for retrieving only part of
	 * the message (headers, etc), the entire message is retrieved.
	 * @exception MessagingException if a messaging error occurred
	 */
	public Message getMessage(int msgnum) throws MessagingException {
		if (!open)
			throw new MessagingException("Folder is not open");
		Message message = (Message)messages.get(new Integer(msgnum));
		if (message==null) {
			message = ((POP3Store)store).getMessage(this, msgnum);
			messages.put(new Integer(msgnum), message);
		}
		return message;
	}
	
	/**
	 * You can't append messages to a POP3 folder.
	 */
	public void appendMessages(Message amessage[]) throws MessagingException {
		throw new MessagingException("Can't append messages to a POP3 folder");
	}

	/**
	 * Does nothing.
	 * The messages <i>must</i> be fetched in their entirety by getMessage(int) -
	 * this is the nature of the POP3 protocol.
	 * @exception MessagingException ignore
	 */
	public void fetch(Message amessage[], FetchProfile fetchprofile) throws MessagingException {
	}

	/**
	 * Returns the subfolders for this folder.
	 */
	public Folder[] list() throws MessagingException {
		switch (type) {
		  case HOLDS_FOLDERS:
			if (inbox==null) inbox = new POP3Folder(store, HOLDS_MESSAGES);
			Folder[] folders = { inbox };
			return folders;
		  default:
			throw new MessagingException("This folder can't contain subfolders");
		}
	}

	/**
	 * Returns the subfolders for this folder.
	 */
	public Folder[] list(String pattern) throws MessagingException {
		return list();
	}
	
	/**
	 * POP3 folders can't have parents.
	 */
	public Folder getParent() throws MessagingException {
		switch (type) {
		  case HOLDS_MESSAGES:
			return ((POP3Store)store).root;
		  default:
			throw new MessagingException("Root folders can't have a parent");
		}
	}

	/**
	 * POP3 folders can't contain subfolders.
	 */
	public Folder getFolder(String s) throws MessagingException {
		switch (type) {
		  case HOLDS_FOLDERS:
			if (inbox==null) inbox = new POP3Folder(store, HOLDS_MESSAGES);
			return inbox;
		  default:
			throw new MessagingException("This folder can't contain subfolders");
		}
	}

	/**
	 * Returns the path separator charcter.
	 */
	public char getSeparator() throws MessagingException {
		return '\u0000';
	}

	// -- These must be overridden to throw exceptions --

	/**
	 * POP3 folders can't be created, deleted, or renamed.
	 */
	public boolean create(int i) throws MessagingException {
		throw new MessagingException("Folder can't be created");
	}

	/**
	 * POP3 folders can't be created, deleted, or renamed.
	 */
	public boolean delete(boolean flag) throws MessagingException {
		throw new MessagingException("Folder can't be deleted");
	}

	/**
	 * POP3 folders can't be created, deleted, or renamed.
	 */
	public boolean renameTo(Folder folder) throws MessagingException {
		throw new MessagingException("Folder can't be renamed");
	}

}