pop3folder.java

此源码是在sun站点上提供的javamail基础上改进。用来解决中文邮件或很多国际间邮件乱码问题。版权属于sun公司。不过当你开发webmail程序时做邮件展示时

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 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License. You can obtain
 * a copy of the License at https://glassfish.dev.java.net/public/CDDL+GPL.html
 * or glassfish/bootstrap/legal/LICENSE.txt.  See the License for the specific
 * language governing permissions and limitations under the License.
 *
 * When distributing the software, include this License Header Notice in each
 * file and include the License file at glassfish/bootstrap/legal/LICENSE.txt.
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/*
 * @(#)POP3Folder.java	1.34 07/05/04
 */

package com.sun.mail.pop3;

import javax.mail.*;
import javax.mail.internet.*;
import javax.mail.event.*;
import java.io.InputStream;
import java.io.BufferedInputStream;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.EOFException;
import java.util.Vector;
import java.util.StringTokenizer;
import java.lang.reflect.Constructor;

import com.sun.mail.util.LineInputStream;

/**
 * A POP3 Folder (can only be "INBOX").
 *
 * See the <a href="package-summary.html">com.sun.mail.pop3</a> package
 * documentation for further information on the POP3 protocol provider. <p>
 *
 * @author      Bill Shannon
 * @author	John Mani (ported to the javax.mail APIs)
 */
public class POP3Folder extends Folder {

    private String name;
    private Protocol port;
    private int total;
    private int size;
    private boolean exists = false;
    private boolean opened = false;
    private Vector message_cache;
    private boolean doneUidl = false;

    POP3Folder(POP3Store store, String name) {
	super(store);
	this.name = name;
	if (name.equalsIgnoreCase("INBOX"))
	    exists = true;
    }

    public String getName() {
	return name;
    }

    public String getFullName() {
	return name;
    }

    public Folder getParent() {
	return new DefaultFolder((POP3Store)store);
    }

    /**
     * Always true for the folder "INBOX", always false for
     * any other name.
     *
     * @return	true for INBOX, false otherwise
     */
    public boolean exists() {
	return exists;
    }

    /**
     * Always throws <code>MessagingException</code> because no POP3 folders
     * can contain subfolders.
     *
     * @exception	MessagingException	always
     */
    public Folder[] list(String pattern) throws MessagingException {
	throw new MessagingException("not a directory");
    }

    /**
     * Always returns a NUL character because POP3 doesn't support a hierarchy.
     *
     * @return	NUL
     */
    public char getSeparator() {
	return '\0';
    }

    /**
     * Always returns Folder.HOLDS_MESSAGES.
     *
     * @return	Folder.HOLDS_MESSAGES
     */
    public int getType() {
	return HOLDS_MESSAGES;
    }

    /**
     * Always returns <code>false</code>; the POP3 protocol doesn't
     * support creating folders.
     *
     * @return	false
     */
    public boolean create(int type) throws MessagingException {
	return false;
    }

    /**
     * Always returns <code>false</code>; the POP3 protocol provides
     * no way to determine when a new message arrives.
     *
     * @return	false
     */
    public boolean hasNewMessages() throws MessagingException {
	return false;    // no way to know
    }

    /**
     * Always throws <code>MessagingException</code> because no POP3 folders
     * can contain subfolders.
     *
     * @exception	MessagingException	always
     */
    public Folder getFolder(String name) throws MessagingException {
	throw new MessagingException("not a directory");
    }

    /**
     * Always throws <code>MethodNotSupportedException</code>
     * because the POP3 protocol doesn't allow the INBOX to
     * be deleted.
     *
     * @exception	MethodNotSupportedException	always
     */
    public boolean delete(boolean recurse) throws MessagingException {
	throw new MethodNotSupportedException("delete");
    }

    /**
     * Always throws <code>MethodNotSupportedException</code>
     * because the POP3 protocol doesn't support multiple folders.
     *
     * @exception	MethodNotSupportedException	always
     */
    public boolean renameTo(Folder f) throws MessagingException {
	throw new MethodNotSupportedException("renameTo");
    }

    /**
     * Throws <code>FolderNotFoundException</code> unless this
     * folder is named "INBOX".
     *
     * @exception	FolderNotFoundException	if not INBOX
     * @exception	AuthenticationException	authentication failures
     * @exception	MessagingException	other open failures
     */
    public synchronized void open(int mode) throws MessagingException {
	checkClosed();
	if (!exists)
	    throw new FolderNotFoundException(this, "folder is not INBOX");

	try {
	    port = ((POP3Store)store).getPort(this);
	    Status s = port.stat();
	    total = s.total;
	    size = s.size;
	    this.mode = mode;
	    opened = true;
	} catch (IOException ioex) {
	    try {
		if (port != null)
		    port.quit();
	    } catch (IOException ioex2) {
		// ignore
	    } finally {
		port = null;
		((POP3Store)store).closePort(this);
	    }
	    throw new MessagingException("Open failed", ioex);
	}

	// Create the message cache vector of appropriate size
	message_cache = new Vector(total);
	message_cache.setSize(total);
	doneUidl = false;

	notifyConnectionListeners(ConnectionEvent.OPENED);
    }

    public synchronized void close(boolean expunge) throws MessagingException {
	checkOpen();

	try {
	    /*
	     * Some POP3 servers will mark messages for deletion when
	     * they're read.  To prevent such messages from being
	     * deleted before the client deletes them, you can set
	     * the mail.pop3.rsetbeforequit property to true.  This
	     * causes us to issue a POP3 RSET command to clear all
	     * the "marked for deletion" flags.  We can then explicitly
	     * delete messages as desired.
	     */
	    if (((POP3Store)store).rsetBeforeQuit)
		port.rset();
	    if (expunge && mode == READ_WRITE) {
		// find all messages marked deleted and issue DELE commands
		POP3Message m;
		for (int i = 0; i < message_cache.size(); i++) {
		    if ((m = (POP3Message)message_cache.elementAt(i)) != null) {
			if (m.isSet(Flags.Flag.DELETED))
			    try {
				port.dele(i + 1);
			    } catch (IOException ioex) {
				throw new MessagingException(
				    "Exception deleting messages during close",
				    ioex);
			    }
		    }
		}
	    }

	    port.quit();
	} catch (IOException ex) {
	    // do nothing
	} finally {
	    port = null;
	    ((POP3Store)store).closePort(this);
	    message_cache = null;
	    opened = false;
	    notifyConnectionListeners(ConnectionEvent.CLOSED);
	}
    }

    public boolean isOpen() {
	if (!opened)
	    return false;
	if (store.isConnected())
	    return true;
	try {