/*
 * Copyright (c) 1997, 2025 Oracle and/or its affiliates. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0, which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 *
 * This Source Code may also be made available under the following Secondary
 * Licenses when the conditions for such availability set forth in the
 * Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
 * version 2 with the GNU Classpath Exception, which is available at
 * https://www.gnu.org/software/classpath/license.html.
 *
 * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
 */

package jakarta.mail.internet;

import jakarta.activation.DataHandler;
import jakarta.mail.Address;
import jakarta.mail.Flags;
import jakarta.mail.Folder;
import jakarta.mail.FolderClosedException;
import jakarta.mail.Header;
import jakarta.mail.IllegalWriteException;
import jakarta.mail.Message;
import jakarta.mail.MessageRemovedException;
import jakarta.mail.MessagingException;
import jakarta.mail.Multipart;
import jakarta.mail.Session;
import jakarta.mail.util.LineOutputStream;
import jakarta.mail.util.StreamProvider;

import java.io.BufferedInputStream;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectStreamException;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;
import java.text.ParseException;
import java.util.ArrayList;
import java.util.Date;
import java.util.Enumeration;
import java.util.List;
import java.util.Properties;
import java.util.ServiceConfigurationError;


/**
 * This class represents a MIME style email message. It implements
 * the <code>Message</code> abstract class and the <code>MimePart</code>
 * interface. <p>
 *
 * Clients wanting to create new MIME style messages will instantiate
 * an empty MimeMessage object and then fill it with appropriate
 * attributes and content. <p>
 *
 * Service providers that implement MIME compliant backend stores may
 * want to subclass MimeMessage and override certain methods to provide
 * specific implementations. The simplest case is probably a provider
 * that generates a MIME style input stream and leaves the parsing of
 * the stream to this class. <p>
 *
 * MimeMessage uses the <code>InternetHeaders</code> class to parse and
 * store the top level RFC 822 headers of a message. <p>
 *
 * The <code>mail.mime.address.strict</code> session or system property
 * controls the parsing of address headers.  By default, strict parsing
 * of address headers is done. If this property is set to <code>"false"</code>,
 * strict parsing is not done and many illegal addresses that sometimes
 * occur in real messages are allowed.  See the <code>InternetAddress</code>
 * class for details.
 *
 * <hr><strong>A note on RFC 822 and MIME headers</strong><p>
 *
 * RFC 822 header fields <strong>must</strong> contain only
 * US-ASCII characters. MIME allows non ASCII characters to be present
 * in certain portions of certain headers, by encoding those characters.
 * RFC 2047 specifies the rules for doing this. The MimeUtility
 * class provided in this package can be used to to achieve this.
 * Callers of the <code>setHeader</code>, <code>addHeader</code>, and
 * <code>addHeaderLine</code> methods are responsible for enforcing
 * the MIME requirements for the specified headers.  In addition, these
 * header fields must be folded (wrapped) before being sent if they
 * exceed the line length limitation for the transport (1000 bytes for
 * SMTP).  Received headers may have been folded.  The application is
 * responsible for folding and unfolding headers as appropriate.
 *
 * @author John Mani
 * @author Bill Shannon
 * @author Max Spivak
 * @author Kanwar Oberoi
 * @see jakarta.mail.internet.MimeUtility
 * @see jakarta.mail.Part
 * @see jakarta.mail.Message
 * @see jakarta.mail.internet.MimePart
 * @see jakarta.mail.internet.InternetAddress
 */

public class MimeMessage extends Message implements MimePart {

    /**
     * The DataHandler object representing this Message's content.
     */
    protected DataHandler dh;

    /**
     * Byte array that holds the bytes of this Message's content.
     */
    protected byte[] content;

    /**
     * If the data for this message was supplied by an
     * InputStream that implements the SharedInputStream interface,
     * <code>contentStream</code> is another such stream representing
     * the content of this message.  In this case, <code>content</code>
     * will be null.
     *
     * @since JavaMail 1.2
     */
    protected InputStream contentStream;

    /**
     * The InternetHeaders object that stores the header
     * of this message.
     */
    protected InternetHeaders headers;

    /**
     * The Flags for this message.
     */
    protected Flags flags;

    /**
     * A flag indicating whether the message has been modified.
     * If the message has not been modified, any data in the
     * <code>content</code> array is assumed to be valid and is used
     * directly in the <code>writeTo</code> method.  This flag is
     * set to true when an empty message is created or when the
     * <code>saveChanges</code> method is called.
     *
     * @since JavaMail 1.2
     */
    protected boolean modified = false;

    /**
     * Does the <code>saveChanges</code> method need to be called on
     * this message?  This flag is set to false by the public constructor
     * and set to true by the <code>saveChanges</code> method.  The
     * <code>writeTo</code> method checks this flag and calls the
     * <code>saveChanges</code> method as necessary.  This avoids the
     * common mistake of forgetting to call the <code>saveChanges</code>
     * method on a newly constructed message.
     *
     * @since JavaMail 1.2
     */
    protected boolean saved = false;

    /**
     * If our content is a Multipart or Message object, we save it
     * the first time it's created by parsing a stream so that changes
     * to the contained objects will not be lost. <p>
     *
     * If this field is not null, it's return by the {@link #getContent}
     * method.  The {@link #getContent} method sets this field if it
     * would return a Multipart or MimeMessage object.  This field is
     * is cleared by the {@link #setDataHandler} method.
     *
     * @since JavaMail 1.5
     */
    protected Object cachedContent;

    // Used to parse dates
    private static final MailDateFormat mailDateFormat = new MailDateFormat();

    // Should addresses in headers be parsed in "strict" mode?
    private boolean strict = true;
    // Is UTF-8 allowed in headers?
    private boolean allowutf8 = false;

    /**
     * Default constructor. An empty message object is created.
     * The <code>headers</code> field is set to an empty InternetHeaders
     * object. The <code>flags</code> field is set to an empty Flags
     * object. The <code>modified</code> flag is set to true.
     *
     * @param session the Sesssion
     */
    public MimeMessage(Session session) {
        super(session);
        modified = true;
        headers = new InternetHeaders();
        flags = new Flags();    // empty flags object
        initConfiguration();
    }

    /**
     * Constructs a MimeMessage by reading and parsing the data from the
     * specified MIME InputStream. The InputStream will be left positioned
     * at the end of the data for the message. Note that the input stream
     * parse is done within this constructor itself. <p>
     *
     * The input stream contains an entire MIME formatted message with
     * headers and data.
     *
     * @param session Session object for this message
     * @param is      the message input stream
     * @throws MessagingException for failures
     */
    public MimeMessage(Session session, InputStream is)
            throws MessagingException {
        super(session);
        flags = new Flags(); // empty Flags object
        initConfiguration();
        parse(is);
        saved = true;
    }

    /**
     * Constructs a new MimeMessage with content initialized from the
     * <code>source</code> MimeMessage.  The new message is independent
     * of the original. <p>
     *
     * Note: The current implementation is rather inefficient, copying
     * the data more times than strictly necessary.
     *
     * @param source the message to copy content from
     * @throws MessagingException for failures
     * @since JavaMail 1.2
     */
    public MimeMessage(MimeMessage source) throws MessagingException {
        super(source.session);
        flags = source.getFlags();
        if (flags == null)    // make sure flags is always set
            flags = new Flags();
        ByteArrayOutputStream bos;
        int size = source.getSize();
        if (size > 0)
            bos = new ByteArrayOutputStream(size);
        else
            bos = new ByteArrayOutputStream();
        try {
            strict = source.strict;
            allowutf8 = source.allowutf8;
            source.writeTo(bos);
            bos.close();
            try (InputStream bis = provider().inputSharedByteArray(bos.toByteArray())) {
                parse(bis);
            }
            saved = true;
        } catch (IOException ex) {
            // should never happen, but just in case...
            throw new MessagingException("IOException while copying message",
                    ex);
        }
    }

    /**
     * Constructs an empty MimeMessage object with the given Folder
     * and message number. <p>
     *
     * This method is for providers subclassing <code>MimeMessage</code>.
     *
     * @param folder the Folder this message is from
     * @param msgnum the number of this message
     */
    protected MimeMessage(Folder folder, int msgnum) {
        super(folder, msgnum);
        flags = new Flags();  // empty Flags object
        saved = true;
        initConfiguration();
    }

    /**
     * Constructs a MimeMessage by reading and parsing the data from the
     * specified MIME InputStream. The InputStream will be left positioned
     * at the end of the data for the message. Note that the input stream
     * parse is done within this constructor itself. <p>
     *
     * This method is for providers subclassing <code>MimeMessage</code>.
     *
     * @param folder The containing folder.
     * @param is     the message input stream
     * @param msgnum Message number of this message within its folder
     * @throws MessagingException for failures
     */
    protected MimeMessage(Folder folder, InputStream is, int msgnum)
            throws MessagingException {
        this(folder, msgnum);
        initConfiguration();
        parse(is);
    }

    /**
     * Constructs a MimeMessage from the given InternetHeaders object
     * and content.
     *
     * This method is for providers subclassing <code>MimeMessage</code>.
     *
     * @param folder  The containing folder.
     * @param headers The headers
     * @param content The message content
     * @param msgnum  Message number of this message within its folder
     * @throws MessagingException for failures
     */
    protected MimeMessage(Folder folder, InternetHeaders headers,
                          byte[] content, int msgnum) throws MessagingException {
        this(folder, msgnum);
        this.headers = headers;
        this.content = content;
        initConfiguration();
    }

    /**
     * Set the configuration based on the session properties or system properties if no session is set.
     */
    private void initConfiguration() {
        Properties props = session != null ? session.getProperties() : System.getProperties();
        strict = MimeUtility.getBooleanProperty(props, "mail.mime.address.strict", true);
        allowutf8 = MimeUtility.getBooleanProperty(props, "mail.mime.allowutf8", false);
    }

    /**
     * Parse the InputStream setting the <code>headers</code> and
     * <code>content</code> fields appropriately.  Also resets the
     * <code>modified</code> flag. <p>
     *
     * This method is intended for use by subclasses that need to
     * control when the InputStream is parsed.
     *
     * @param is The message input stream
     * @throws MessagingException for failures
     */
    protected void parse(InputStream is) throws MessagingException {

        if (!(is instanceof ByteArrayInputStream) &&
                !(is instanceof BufferedInputStream) &&
                !(is instanceof SharedInputStream))
            is = new BufferedInputStream(is);

        headers = createInternetHeaders(is);

        if (is instanceof SharedInputStream) {
            SharedInputStream sis = (SharedInputStream) is;
            contentStream = sis.newStream(sis.getPosition(), -1);
        } else {
            try {
                content = MimeUtility.getBytes(is);
            } catch (IOException ioex) {
                throw new MessagingException("IOException", ioex);
            }
        }

        modified = false;
    }

    /**
     * Returns the value of the RFC 822 "From" header fields. If this
     * header field is absent, the "Sender" header field is used.
     * If the "Sender" header field is also absent, <code>null</code>
     * is returned.<p>
     *
     * This implementation uses the <code>getHeader</code> method
     * to obtain the requisite header field.
     *
     * @return Address object
     * @throws MessagingException for failures
     * @see #headers
     */
    @Override
    public Address[] getFrom() throws MessagingException {
        Address[] a = getAddressHeader("From");
        if (a == null)
            a = getAddressHeader("Sender");

        return a;
    }

    /**
     * Set the RFC 822 "From" header field. Any existing values are
     * replaced with the given address. If address is <code>null</code>,
     * this header is removed.
     *
     * @param address the sender of this message
     * @throws IllegalWriteException if the underlying
     *                                  implementation does not support modification
     *                                  of existing values
     * @throws IllegalStateException if this message is
     *                                  obtained from a READ_ONLY folder.
     * @throws MessagingException    for other failures
     */
    @Override
    public void setFrom(Address address) throws MessagingException {
        if (address == null)
            removeHeader("From");
        else
            setAddressHeader("From", new Address[]{address});
    }

    /**
     * Set the RFC 822 "From" header field. Any existing values are
     * replaced with the given addresses. If address is <code>null</code>,
     * this header is removed.
     *
     * @param address the sender(s) of this message
     * @throws IllegalWriteException if the underlying
     *                                  implementation does not support modification
     *                                  of existing values
     * @throws IllegalStateException if this message is
     *                                  obtained from a READ_ONLY folder.
     * @throws MessagingException    for other failures
     * @since JvaMail 1.5
     */
    public void setFrom(String address) throws MessagingException {
        if (address == null)
            removeHeader("From");
        else
            setAddressHeader("From", InternetAddress.parse(address));
    }

    /**
     * Set the RFC 822 "From" header field using the value of the
     * <code>InternetAddress.getLocalAddress</code> method.
     *
     * @throws IllegalWriteException if the underlying
     *                                  implementation does not support modification
     *                                  of existing values
     * @throws IllegalStateException if this message is
     *                                  obtained from a READ_ONLY folder.
     * @throws MessagingException    for other failures
     */
    @Override
    public void setFrom() throws MessagingException {
        InternetAddress me = null;
        try {
            me = InternetAddress._getLocalAddress(session);
        } catch (Exception ex) {
            // if anything goes wrong (SecurityException, UnknownHostException),
            // chain the exception
            throw new MessagingException("No From address", ex);
        }
        if (me != null)
            setFrom(me);
        else
            throw new MessagingException("No From address");
    }

    /**
     * Add the specified addresses to the existing "From" field. If
     * the "From" field does not already exist, it is created.
     *
     * @param addresses the senders of this message
     * @throws IllegalWriteException if the underlying
     *                                  implementation does not support modification
     *                                  of existing values
     * @throws IllegalStateException if this message is
     *                                  obtained from a READ_ONLY folder.
     * @throws MessagingException    for other failures
     */
    @Override
    public void addFrom(Address[] addresses) throws MessagingException {
        addAddressHeader("From", addresses);
    }

    /**
     * Returns the value of the RFC 822 "Sender" header field.
     * If the "Sender" header field is absent, <code>null</code>
     * is returned.<p>
     *
     * This implementation uses the <code>getHeader</code> method
     * to obtain the requisite header field.
     *
     * @return Address object
     * @throws MessagingException for failures
     * @see #headers
     * @since JavaMail 1.3
     */
    public Address getSender() throws MessagingException {
        Address[] a = getAddressHeader("Sender");
        if (a == null || a.length == 0)
            return null;
        return a[0];    // there can be only one
    }

    /**
     * Set the RFC 822 "Sender" header field. Any existing values are
     * replaced with the given address. If address is <code>null</code>,
     * this header is removed.
     *
     * @param address the sender of this message
     * @throws IllegalWriteException if the underlying
     *                                  implementation does not support modification
     *                                  of existing values
     * @throws IllegalStateException if this message is
     *                                  obtained from a READ_ONLY folder.
     * @throws MessagingException    for other failures
     * @since JavaMail 1.3
     */
    public void setSender(Address address) throws MessagingException {
        if (address == null)
            removeHeader("Sender");
        else
            setAddressHeader("Sender", new Address[]{address});
    }

    /**
     * This inner class extends the jakarta.mail.Message.RecipientType
     * class to add additional RecipientTypes. The one additional
     * RecipientType currently defined here is NEWSGROUPS.
     *
     * @see jakarta.mail.Message.RecipientType
     */
    public static class RecipientType extends Message.RecipientType {

        private static final long serialVersionUID = -5468290701714395543L;

        /**
         * The "Newsgroup" (Usenet news) recipients.
         */
        public static final RecipientType NEWSGROUPS =
                new RecipientType("Newsgroups");

        /**
         * Constructor for use by subclasses.
         *
         * @param type the recipient type
         */
        protected RecipientType(String type) {
            super(type);
        }

        @Override
        protected Object readResolve() throws ObjectStreamException {
            if (type.equals("Newsgroups"))
                return NEWSGROUPS;
            else
                return super.readResolve();
        }
    }

    /**
     * Returns the recepients specified by the type. The mapping
     * between the type and the corresponding RFC 822 header is
     * as follows:
     * <pre>
     * 		Message.RecipientType.TO		"To"
     * 		Message.RecipientType.CC		"Cc"
     * 		Message.RecipientType.BCC		"Bcc"
     * 		MimeMessage.RecipientType.NEWSGROUPS	"Newsgroups"
     * </pre><br>
     *
     * Returns null if the header specified by the type is not found
     * or if its value is empty. <p>
     *
     * This implementation uses the <code>getHeader</code> method
     * to obtain the requisite header field.
     *
     * @param type Type of recepient
     * @return array of Address objects
     * @throws MessagingException if header could not
     *                               be retrieved
     * @throws AddressException   if the header is misformatted
     * @see #headers
     * @see jakarta.mail.Message.RecipientType#TO
     * @see jakarta.mail.Message.RecipientType#CC
     * @see jakarta.mail.Message.RecipientType#BCC
     * @see jakarta.mail.internet.MimeMessage.RecipientType#NEWSGROUPS
     */
    @Override
    public Address[] getRecipients(Message.RecipientType type)
            throws MessagingException {
        if (type == RecipientType.NEWSGROUPS) {
            String s = getHeader("Newsgroups", ",");
            return (s == null) ? null : NewsAddress.parse(s);
        } else
            return getAddressHeader(getHeaderName(type));
    }

    /**
     * Get all the recipient addresses for the message.
     * Extracts the TO, CC, BCC, and NEWSGROUPS recipients.
     *
     * @return array of Address objects
     * @throws MessagingException for failures
     * @see jakarta.mail.Message.RecipientType#TO
     * @see jakarta.mail.Message.RecipientType#CC
     * @see jakarta.mail.Message.RecipientType#BCC
     * @see jakarta.mail.internet.MimeMessage.RecipientType#NEWSGROUPS
     */
    @Override
    public Address[] getAllRecipients() throws MessagingException {
        Address[] all = super.getAllRecipients();
        Address[] ng = getRecipients(RecipientType.NEWSGROUPS);

        if (ng == null)
            return all;        // the common case
        if (all == null)
            return ng;        // a rare case

        Address[] addresses = new Address[all.length + ng.length];
        System.arraycopy(all, 0, addresses, 0, all.length);
        System.arraycopy(ng, 0, addresses, all.length, ng.length);
        return addresses;
    }

    /**
     * Set the specified recipient type to the given addresses.
     * If the address parameter is <code>null</code>, the corresponding
     * recipient field is removed.
     *
     * @param type      Recipient type
     * @param addresses Addresses
     * @throws IllegalWriteException if the underlying
     *                                  implementation does not support modification
     *                                  of existing values
     * @throws IllegalStateException if this message is
     *                                  obtained from a READ_ONLY folder.
     * @throws MessagingException    for other failures
     * @see #getRecipients
     */
    @Override
    public void setRecipients(Message.RecipientType type, Address[] addresses)
            throws MessagingException {
        if (type == RecipientType.NEWSGROUPS) {
            if (addresses == null || addresses.length == 0)
                removeHeader("Newsgroups");
            else
                setHeader("Newsgroups", NewsAddress.toString(addresses));
        } else
            setAddressHeader(getHeaderName(type), addresses);
    }

    /**
     * Set the specified recipient type to the given addresses.
     * If the address parameter is <code>null</code>, the corresponding
     * recipient field is removed.
     *
     * @param type      Recipient type
     * @param addresses Addresses
     * @throws AddressException      if the attempt to parse the
     *                                  addresses String fails
     * @throws IllegalWriteException if the underlying
     *                                  implementation does not support modification
     *                                  of existing values
     * @throws IllegalStateException if this message is
     *                                  obtained from a READ_ONLY folder.
     * @throws MessagingException    for other failures
     * @see #getRecipients
     * @since JavaMail 1.2
     */
    public void setRecipients(Message.RecipientType type, String addresses)
            throws MessagingException {
        if (type == RecipientType.NEWSGROUPS) {
            if (addresses == null || addresses.length() == 0)
                removeHeader("Newsgroups");
            else
                setHeader("Newsgroups", addresses);
        } else
            setAddressHeader(getHeaderName(type),
                    addresses == null ? null : InternetAddress.parse(addresses));
    }

    /**
     * Add the given addresses to the specified recipient type.
     *
     * @param type      Recipient type
     * @param addresses Addresses
     * @throws IllegalWriteException if the underlying
     *                                  implementation does not support modification
     *                                  of existing values
     * @throws IllegalStateException if this message is
     *                                  obtained from a READ_ONLY folder.
     * @throws MessagingException    for other failures
     */
    @Override
    public void addRecipients(Message.RecipientType type, Address[] addresses)
            throws MessagingException {
        if (type == RecipientType.NEWSGROUPS) {
            String s = NewsAddress.toString(addresses);
            if (s != null)
                addHeader("Newsgroups", s);
        } else
            addAddressHeader(getHeaderName(type), addresses);
    }

    /**
     * Add the given addresses to the specified recipient type.
     *
     * @param type      Recipient type
     * @param addresses Addresses
     * @throws AddressException      if the attempt to parse the
     *                                  addresses String fails
     * @throws IllegalWriteException if the underlying
     *                                  implementation does not support modification
     *                                  of existing values
     * @throws IllegalStateException if this message is
     *                                  obtained from a READ_ONLY folder.
     * @throws MessagingException    for other failures
     * @since JavaMail 1.2
     */
    public void addRecipients(Message.RecipientType type, String addresses)
            throws MessagingException {
        if (type == RecipientType.NEWSGROUPS) {
            if (addresses != null && addresses.length() != 0)
                addHeader("Newsgroups", addresses);
        } else
            addAddressHeader(getHeaderName(type),
                    InternetAddress.parse(addresses));
    }

    /**
     * Return the value of the RFC 822 "Reply-To" header field. If
     * this header is unavailable or its value is absent, then
     * the <code>getFrom</code> method is called and its value is returned.
     *
     * This implementation uses the <code>getHeader</code> method
     * to obtain the requisite header field.
     *
     * @throws MessagingException for failures
     * @see #headers
     */
    @Override
    public Address[] getReplyTo() throws MessagingException {
        Address[] a = getAddressHeader("Reply-To");
        if (a == null || a.length == 0)
            a = getFrom();
        return a;
    }

    /**
     * Set the RFC 822 "Reply-To" header field. If the address
     * parameter is <code>null</code>, this header is removed.
     *
     * @throws IllegalWriteException if the underlying
     *                                  implementation does not support modification
     *                                  of existing values
     * @throws IllegalStateException if this message is
     *                                  obtained from a READ_ONLY folder.
     * @throws MessagingException    for other failures
     */
    @Override
    public void setReplyTo(Address[] addresses) throws MessagingException {
        setAddressHeader("Reply-To", addresses);
    }

    // Convenience method to get addresses
    private Address[] getAddressHeader(String name)
            throws MessagingException {
        String s = getHeader(name, ",");
        return (s == null) ? null : InternetAddress.parseHeader(s, strict);
    }

    // Convenience method to set addresses
    private void setAddressHeader(String name, Address[] addresses)
            throws MessagingException {
        String s;
        if (allowutf8)
            s = InternetAddress.toUnicodeString(addresses, name.length() + 2);
        else
            s = InternetAddress.toString(addresses, name.length() + 2);
        if (s == null)
            removeHeader(name);
        else
            setHeader(name, s);
    }

    private void addAddressHeader(String name, Address[] addresses)
            throws MessagingException {
        if (addresses == null || addresses.length == 0)
            return;
        Address[] a = getAddressHeader(name);
        Address[] anew;
        if (a == null || a.length == 0)
            anew = addresses;
        else {
            anew = new Address[a.length + addresses.length];
            System.arraycopy(a, 0, anew, 0, a.length);
            System.arraycopy(addresses, 0, anew, a.length, addresses.length);
        }
        String s;
        if (allowutf8)
            s = InternetAddress.toUnicodeString(anew, name.length() + 2);
        else
            s = InternetAddress.toString(anew, name.length() + 2);
        if (s == null)
            return;
        setHeader(name, s);
    }

    /**
     * Returns the value of the "Subject" header field. Returns null
     * if the subject field is unavailable or its value is absent. <p>
     *
     * If the subject is encoded as per RFC 2047, it is decoded and
     * converted into Unicode. If the decoding or conversion fails, the
     * raw data is returned as is. <p>
     *
     * This implementation uses the <code>getHeader</code> method
     * to obtain the requisite header field.
     *
     * @return Subject
     * @throws MessagingException for failures
     * @see #headers
     */
    @Override
    public String getSubject() throws MessagingException {
        String rawvalue = getHeader("Subject", null);

        if (rawvalue == null)
            return null;

        try {
            return MimeUtility.decodeText(MimeUtility.unfold(rawvalue));
        } catch (UnsupportedEncodingException ex) {
            return rawvalue;
        }
    }

    /**
     * Set the "Subject" header field. If the subject contains
     * non US-ASCII characters, it will be encoded using the
     * platform's default charset. If the subject contains only
     * US-ASCII characters, no encoding is done and it is used
     * as-is. If the subject is null, the existing "Subject" field
     * is removed. <p>
     *
     * The application must ensure that the subject does not contain
     * any line breaks. <p>
     *
     * Note that if the charset encoding process fails, a
     * MessagingException is thrown, and an UnsupportedEncodingException
     * is included in the chain of nested exceptions within the
     * MessagingException.
     *
     * @param subject The subject
     * @throws IllegalWriteException if the underlying
     *                                  implementation does not support modification
     *                                  of existing values
     * @throws IllegalStateException if this message is
     *                                  obtained from a READ_ONLY folder.
     * @throws MessagingException    for other failures
     */
    @Override
    public void setSubject(String subject) throws MessagingException {
        setSubject(subject, null);
    }

    /**
     * Set the "Subject" header field. If the subject contains non
     * US-ASCII characters, it will be encoded using the specified
     * charset. If the subject contains only US-ASCII characters, no
     * encoding is done and it is used as-is. If the subject is null,
     * the existing "Subject" header field is removed. <p>
     *
     * The application must ensure that the subject does not contain
     * any line breaks. <p>
     *
     * Note that if the charset encoding process fails, a
     * MessagingException is thrown, and an UnsupportedEncodingException
     * is included in the chain of nested exceptions within the
     * MessagingException.
     *
     * @param subject The subject
     * @param charset The charset
     * @throws IllegalWriteException if the underlying
     *                                  implementation does not support modification
     *                                  of existing values
     * @throws IllegalStateException if this message is
     *                                  obtained from a READ_ONLY folder.
     * @throws MessagingException    for other failures
     */
    public void setSubject(String subject, String charset)
            throws MessagingException {
        if (subject == null) {
            removeHeader("Subject");
        } else {
            try {
                setHeader("Subject", MimeUtility.fold(9,
                        MimeUtility.encodeText(subject, charset, null)));
            } catch (UnsupportedEncodingException uex) {
                throw new MessagingException("Encoding error", uex);
            }
        }
    }

    /**
     * Returns the value of the RFC 822 "Date" field. This is the date
     * on which this message was sent. Returns null if this field is
     * unavailable or its value is absent. <p>
     *
     * This implementation uses the <code>getHeader</code> method
     * to obtain the requisite header field.
     *
     * @return The sent Date
     * @throws MessagingException for failures
     */
    @Override
    public Date getSentDate() throws MessagingException {
        String s = getHeader("Date", null);
        if (s != null) {
            try {
                synchronized (mailDateFormat) {
                    return mailDateFormat.parse(s);
                }
            } catch (ParseException pex) {
                return null;
            }
        }

        return null;
    }

    /**
     * Set the RFC 822 "Date" header field. This is the date on which the
     * creator of the message indicates that the message is complete
     * and ready for delivery. If the date parameter is
     * <code>null</code>, the existing "Date" field is removed.
     *
     * @throws IllegalWriteException if the underlying
     *                                  implementation does not support modification
     * @throws IllegalStateException if this message is
     *                                  obtained from a READ_ONLY folder.
     * @throws MessagingException    for other failures
     */
    @Override
    public void setSentDate(Date d) throws MessagingException {
        if (d == null)
            removeHeader("Date");
        else {
            synchronized (mailDateFormat) {
                setHeader("Date", mailDateFormat.format(d));
            }
        }
    }

    /**
     * Returns the Date on this message was received. Returns
     * <code>null</code> if this date cannot be obtained. <p>
     *
     * Note that RFC 822 does not define a field for the received
     * date. Hence only implementations that can provide this date
     * need return a valid value. <p>
     *
     * This implementation returns <code>null</code>.
     *
     * @return the date this message was received
     * @throws MessagingException for failures
     */
    @Override
    public Date getReceivedDate() throws MessagingException {
        return null;
    }

    /**
     * Return the size of the content of this message in bytes.
     * Return -1 if the size cannot be determined. <p>
     *
     * Note that this number may not be an exact measure of the
     * content size and may or may not account for any transfer
     * encoding of the content. <p>
     *
     * This implementation returns the size of the <code>content</code>
     * array (if not null), or, if <code>contentStream</code> is not
     * null, and the <code>available</code> method returns a positive
     * number, it returns that number as the size.  Otherwise, it returns
     * -1.
     *
     * @return size of content in bytes
     * @throws MessagingException for failures
     */
    @Override
    public int getSize() throws MessagingException {
        if (content != null)
            return content.length;
        if (contentStream != null) {
            try {
                int size = contentStream.available();
                // only believe the size if it's greater than zero, since zero
                // is the default returned by the InputStream class itself
                if (size > 0)
                    return size;
            } catch (IOException ex) {
                // ignore it
            }
        }
        return -1;
    }

    /**
     * Return the number of lines for the content of this message.
     * Return -1 if this number cannot be determined. <p>
     *
     * Note that this number may not be an exact measure of the
     * content length and may or may not account for any transfer
     * encoding of the content. <p>
     *
     * This implementation returns -1.
     *
     * @return number of lines in the content.
     * @throws MessagingException for failures
     */
    @Override
    public int getLineCount() throws MessagingException {
        return -1;
    }

    /**
     * Returns the value of the RFC 822 "Content-Type" header field.
     * This represents the content-type of the content of this
     * message. This value must not be null. If this field is
     * unavailable, "text/plain" should be returned. <p>
     *
     * This implementation uses the <code>getHeader</code> method
     * to obtain the requisite header field.
     *
     * @return The ContentType of this part
     * @throws MessagingException for failures
     * @see jakarta.activation.DataHandler
     */
    @Override
    public String getContentType() throws MessagingException {
        String s = getHeader("Content-Type", null);
        s = MimeUtil.cleanContentType(this, s);
        if (s == null)
            return "text/plain";
        return s;
    }

    /**
     * Is this Part of the specified MIME type?  This method
     * compares <strong>only the <code>primaryType</code> and
     * <code>subType</code></strong>.
     * The parameters of the content types are ignored. <p>
     *
     * For example, this method will return <code>true</code> when
     * comparing a Part of content type <strong>"text/plain"</strong>
     * with <strong>"text/plain; charset=foobar"</strong>. <p>
     *
     * If the <code>subType</code> of <code>mimeType</code> is the
     * special character '*', then the subtype is ignored during the
     * comparison.
     *
     * @param mimeType the MIME type to check
     * @return true if it matches the MIME type
     * @throws MessagingException for failures
     */
    @Override
    public boolean isMimeType(String mimeType) throws MessagingException {
        return MimeBodyPart.isMimeType(this, mimeType);
    }

    /**
     * Returns the disposition from the "Content-Disposition" header field.
     * This represents the disposition of this part. The disposition
     * describes how the part should be presented to the user. <p>
     *
     * If the Content-Disposition field is unavailable,
     * <code>null</code> is returned. <p>
     *
     * This implementation uses the <code>getHeader</code> method
     * to obtain the requisite header field.
     *
     * @return disposition of this part, or null if unknown
     * @throws MessagingException for failures
     */
    @Override
    public String getDisposition() throws MessagingException {
        return MimeBodyPart.getDisposition(this);
    }

    /**
     * Set the disposition in the "Content-Disposition" header field
     * of this body part.  If the disposition is null, any existing
     * "Content-Disposition" header field is removed.
     *
     * @throws IllegalWriteException if the underlying
     *                                  implementation does not support modification
     * @throws IllegalStateException if this message is
     *                                  obtained from a READ_ONLY folder.
     * @throws MessagingException    for other failures
     */
    @Override
    public void setDisposition(String disposition) throws MessagingException {
        MimeBodyPart.setDisposition(this, disposition);
    }

    /**
     * Returns the content transfer encoding from the
     * "Content-Transfer-Encoding" header
     * field. Returns <code>null</code> if the header is unavailable
     * or its value is absent. <p>
     *
     * This implementation uses the <code>getHeader</code> method
     * to obtain the requisite header field.
     *
     * @return content-transfer-encoding
     * @throws MessagingException for failures
     */
    @Override
    public String getEncoding() throws MessagingException {
        return MimeBodyPart.getEncoding(this);
    }

    /**
     * Returns the value of the "Content-ID" header field. Returns
     * <code>null</code> if the field is unavailable or its value is
     * absent. <p>
     *
     * This implementation uses the <code>getHeader</code> method
     * to obtain the requisite header field.
     *
     * @return content-ID
     * @throws MessagingException for failures
     */
    @Override
    public String getContentID() throws MessagingException {
        return getHeader("Content-ID", null);
    }

    /**
     * Set the "Content-ID" header field of this Message.
     * If the <code>cid</code> parameter is null, any existing
     * "Content-ID" is removed.
     *
     * @param cid the content ID
     * @throws IllegalWriteException if the underlying
     *                                  implementation does not support modification
     * @throws IllegalStateException if this message is
     *                                  obtained from a READ_ONLY folder.
     * @throws MessagingException    for other failures
     */
    public void setContentID(String cid) throws MessagingException {
        if (cid == null)
            removeHeader("Content-ID");
        else
            setHeader("Content-ID", cid);
    }

    /**
     * Return the value of the "Content-MD5" header field. Returns
     * <code>null</code> if this field is unavailable or its value
     * is absent. <p>
     *
     * This implementation uses the <code>getHeader</code> method
     * to obtain the requisite header field.
     *
     * @return content-MD5
     * @throws MessagingException for failures
     */
    @Override
    public String getContentMD5() throws MessagingException {
        return getHeader("Content-MD5", null);
    }

    /**
     * Set the "Content-MD5" header field of this Message.
     *
     * @throws IllegalWriteException if the underlying
     *                                  implementation does not support modification
     * @throws IllegalStateException if this message is
     *                                  obtained from a READ_ONLY folder.
     * @throws MessagingException    for other failures
     */
    @Override
    public void setContentMD5(String md5) throws MessagingException {
        setHeader("Content-MD5", md5);
    }

    /**
     * Returns the "Content-Description" header field of this Message.
     * This typically associates some descriptive information with
     * this part. Returns null if this field is unavailable or its
     * value is absent. <p>
     *
     * If the Content-Description field is encoded as per RFC 2047,
     * it is decoded and converted into Unicode. If the decoding or
     * conversion fails, the raw data is returned as-is <p>
     *
     * This implementation uses the <code>getHeader</code> method
     * to obtain the requisite header field.
     *
     * @return content-description
     * @throws MessagingException for failures
     */
    @Override
    public String getDescription() throws MessagingException {
        return MimeBodyPart.getDescription(this);
    }

    /**
     * Set the "Content-Description" header field for this Message.
     * If the description parameter is <code>null</code>, then any
     * existing "Content-Description" fields are removed. <p>
     *
     * If the description contains non US-ASCII characters, it will
     * be encoded using the platform's default charset. If the
     * description contains only US-ASCII characters, no encoding
     * is done and it is used as-is. <p>
     *
     * Note that if the charset encoding process fails, a
     * MessagingException is thrown, and an UnsupportedEncodingException
     * is included in the chain of nested exceptions within the
     * MessagingException.
     *
     * @param description content-description
     * @throws IllegalWriteException if the underlying
     *                                  implementation does not support modification
     * @throws IllegalStateException if this message is
     *                                  obtained from a READ_ONLY folder.
     * @throws MessagingException    An
     *                                  UnsupportedEncodingException may be included
     *                                  in the exception chain if the charset
     *                                  conversion fails.
     */
    @Override
    public void setDescription(String description) throws MessagingException {
        setDescription(description, null);
    }

    /**
     * Set the "Content-Description" header field for this Message.
     * If the description parameter is <code>null</code>, then any
     * existing "Content-Description" fields are removed. <p>
     *
     * If the description contains non US-ASCII characters, it will
     * be encoded using the specified charset. If the description
     * contains only US-ASCII characters, no encoding  is done and
     * it is used as-is. <p>
     *
     * Note that if the charset encoding process fails, a
     * MessagingException is thrown, and an UnsupportedEncodingException
     * is included in the chain of nested exceptions within the
     * MessagingException.
     *
     * @param description Description
     * @param charset     Charset for encoding
     * @throws IllegalWriteException if the underlying
     *                                  implementation does not support modification
     * @throws IllegalStateException if this message is
     *                                  obtained from a READ_ONLY folder.
     * @throws MessagingException    An
     *                                  UnsupportedEncodingException may be included
     *                                  in the exception chain if the charset
     *                                  conversion fails.
     */
    public void setDescription(String description, String charset)
            throws MessagingException {
        MimeBodyPart.setDescription(this, description, charset);
    }

    /**
     * Get the languages specified in the "Content-Language" header
     * field of this message. The Content-Language header is defined by
     * RFC 1766. Returns <code>null</code> if this field is unavailable
     * or its value is absent. <p>
     *
     * This implementation uses the <code>getHeader</code> method
     * to obtain the requisite header field.
     *
     * @return value of content-language header.
     * @throws MessagingException for failures
     */
    @Override
    public String[] getContentLanguage() throws MessagingException {
        return MimeBodyPart.getContentLanguage(this);
    }

    /**
     * Set the "Content-Language" header of this MimePart. The
     * Content-Language header is defined by RFC 1766.
     *
     * @param languages array of language tags
     * @throws IllegalWriteException if the underlying
     *                                  implementation does not support modification
     * @throws IllegalStateException if this message is
     *                                  obtained from a READ_ONLY folder.
     * @throws MessagingException    for other failures
     */
    @Override
    public void setContentLanguage(String[] languages)
            throws MessagingException {
        MimeBodyPart.setContentLanguage(this, languages);
    }

    /**
     * Returns the value of the "Message-ID" header field. Returns
     * null if this field is unavailable or its value is absent. <p>
     *
     * The default implementation provided here uses the
     * <code>getHeader</code> method to return the value of the
     * "Message-ID" field.
     *
     * @return Message-ID
     * @throws MessagingException if the retrieval of this field
     *                               causes any exception.
     * @see jakarta.mail.search.MessageIDTerm
     * @since JavaMail 1.1
     */
    public String getMessageID() throws MessagingException {
        return getHeader("Message-ID", null);
    }

    /**
     * Get the filename associated with this Message. <p>
     *
     * Returns the value of the "filename" parameter from the
     * "Content-Disposition" header field of this message. If it's
     * not available, returns the value of the "name" parameter from
     * the "Content-Type" header field of this BodyPart.
     * Returns <code>null</code> if both are absent. <p>
     *
     * If the <code>mail.mime.encodefilename</code> System property
     * is set to true, the {@link MimeUtility#decodeText
     * MimeUtility.decodeText} method will be used to decode the
     * filename.  While such encoding is not supported by the MIME
     * spec, many mailers use this technique to support non-ASCII
     * characters in filenames.  The default value of this property
     * is false.
     *
     * @return filename
     * @throws MessagingException for failures
     */
    @Override
    public String getFileName() throws MessagingException {
        return MimeBodyPart.getFileName(this);
    }

    /**
     * Set the filename associated with this part, if possible. <p>
     *
     * Sets the "filename" parameter of the "Content-Disposition"
     * header field of this message. <p>
     *
     * If the <code>mail.mime.encodefilename</code> System property
     * is set to true, the {@link MimeUtility#encodeText
     * MimeUtility.encodeText} method will be used to encode the
     * filename.  While such encoding is not supported by the MIME
     * spec, many mailers use this technique to support non-ASCII
     * characters in filenames.  The default value of this property
     * is false.
     *
     * @throws IllegalWriteException if the underlying
     *                                  implementation does not support modification
     * @throws IllegalStateException if this message is
     *                                  obtained from a READ_ONLY folder.
     * @throws MessagingException    for other failures
     */
    @Override
    public void setFileName(String filename) throws MessagingException {
        MimeBodyPart.setFileName(this, filename);
    }

    private String getHeaderName(Message.RecipientType type)
            throws MessagingException {
        String headerName;

        if (type == Message.RecipientType.TO)
            headerName = "To";
        else if (type == Message.RecipientType.CC)
            headerName = "Cc";
        else if (type == Message.RecipientType.BCC)
            headerName = "Bcc";
        else if (type == MimeMessage.RecipientType.NEWSGROUPS)
            headerName = "Newsgroups";
        else
            throw new MessagingException("Invalid Recipient Type");
        return headerName;
    }


    /**
     * Return a decoded input stream for this Message's "content". <p>
     *
     * This implementation obtains the input stream from the DataHandler,
     * that is, it invokes <code>getDataHandler().getInputStream()</code>.
     *
     * @return an InputStream
     * @throws IOException        this is typically thrown by the
     *                               DataHandler. Refer to the documentation for
     *                               jakarta.activation.DataHandler for more details.
     * @throws MessagingException for other failures
     * @see #getContentStream
     * @see jakarta.activation.DataHandler#getInputStream
     */
    @Override
    public InputStream getInputStream()
            throws IOException, MessagingException {
        return getDataHandler().getInputStream();
    }

    /**
     * Produce the raw bytes of the content. This method is used during
     * parsing, to create a DataHandler object for the content. Subclasses
     * that can provide a separate input stream for just the message
     * content might want to override this method. <p>
     *
     * This implementation returns a SharedInputStream, if
     * <code>contentStream</code> is not null.  Otherwise, it
     * returns a ByteArrayInputStream constructed
     * out of the <code>content</code> byte array.
     *
     * @return an InputStream containing the raw bytes
     * @throws MessagingException for failures
     * @see #content
     */
    protected InputStream getContentStream() throws MessagingException {
        if (contentStream != null)
            return ((SharedInputStream) contentStream).newStream(0, -1);
        if (content != null) {
            return provider().inputSharedByteArray(content);
        }
        throw new MessagingException("No MimeMessage content");
    }

    /**
     * Return an InputStream to the raw data with any Content-Transfer-Encoding
     * intact.  This method is useful if the "Content-Transfer-Encoding"
     * header is incorrect or corrupt, which would prevent the
     * <code>getInputStream</code> method or <code>getContent</code> method
     * from returning the correct data.  In such a case the application may
     * use this method and attempt to decode the raw data itself. <p>
     *
     * This implementation simply calls the <code>getContentStream</code>
     * method.
     *
     * @return an InputStream containing the raw bytes
     * @throws MessagingException for failures
     * @see #getInputStream
     * @see #getContentStream
     * @since JavaMail 1.2
     */
    public InputStream getRawInputStream() throws MessagingException {
        return getContentStream();
    }

    /**
     * Return a DataHandler for this Message's content. <p>
     *
     * The implementation provided here works approximately as follows.
     * Note the use of the <code>getContentStream</code> method to
     * generate the byte stream for the content. Also note that
     * any transfer-decoding is done automatically within this method.
     *
     * <blockquote><pre>
     *  getDataHandler() {
     *      if (dh == null) {
     *          dh = new DataHandler(new MimePartDataSource(this));
     *      }
     *      return dh;
     *  }
     *
     *  class MimePartDataSource implements DataSource {
     *      public getInputStream() {
     *          return MimeUtility.decode(
     * 		     getContentStream(), getEncoding());
     *      }
     *
     * 		.... &lt;other DataSource methods&gt;
     *  }
     * </pre></blockquote>
     *
     * @throws MessagingException for failures
     */
    @Override
    public synchronized DataHandler getDataHandler()
            throws MessagingException {
        if (dh == null)
            dh = new MimeBodyPart.MimePartDataHandler(this);
        return dh;
    }

    /**
     * Return the content as a Java object. The type of this
     * object is dependent on the content itself. For
     * example, the native format of a "text/plain" content
     * is usually a String object. The native format for a "multipart"
     * message is always a Multipart subclass. For content types that are
     * unknown to the DataHandler system, an input stream is returned
     * as the content. <p>
     *
     * This implementation obtains the content from the DataHandler,
     * that is, it invokes <code>getDataHandler().getContent()</code>.
     * If the content is a Multipart or Message object and was created by
     * parsing a stream, the object is cached and returned in subsequent
     * calls so that modifications to the content will not be lost.
     *
     * @return Object
     * @throws IOException        this is typically thrown by the
     *                               DataHandler. Refer to the documentation for
     *                               jakarta.activation.DataHandler for more details.
     * @throws MessagingException for other failures
     * @see jakarta.mail.Part
     * @see jakarta.activation.DataHandler#getContent
     */
    @Override
    public Object getContent() throws IOException, MessagingException {
        if (cachedContent != null)
            return cachedContent;
        Object c;
        try {
            c = getDataHandler().getContent();
        } catch (IOException e) {
            if (e.getCause() instanceof FolderClosedException) {
                FolderClosedException fce = (FolderClosedException) e.getCause();
                throw new FolderClosedException(fce.getFolder(), e.getMessage(), e);
            } else if (e.getCause() instanceof MessagingException) {
                throw new MessageRemovedException(e.getMessage(), e);
            } else {
                throw e;
            }
        }
        if (MimeBodyPart.cacheMultipart &&
                (c instanceof Multipart || c instanceof Message) &&
                (content != null || contentStream != null)) {
            cachedContent = c;
            /*
             * We may abandon the input stream so make sure
             * the MimeMultipart has consumed the stream.
             */
            if (c instanceof MimeMultipart)
                ((MimeMultipart) c).parse();
        }
        return c;
    }

    /**
     * This method provides the mechanism to set this part's content.
     * The given DataHandler object should wrap the actual content.
     *
     * @param dh The DataHandler for the content.
     * @throws IllegalWriteException if the underlying
     *                                  implementation does not support modification
     * @throws IllegalStateException if this message is
     *                                  obtained from a READ_ONLY folder.
     * @throws MessagingException    for other failures
     */
    @Override
    public synchronized void setDataHandler(DataHandler dh)
            throws MessagingException {
        this.dh = dh;
        cachedContent = null;
        MimeBodyPart.invalidateContentHeaders(this);
    }

    /**
     * A convenience method for setting this Message's content. <p>
     *
     * The content is wrapped in a DataHandler object. Note that a
     * DataContentHandler class for the specified type should be
     * available to the JavaMail implementation for this to work right.
     * i.e., to do <code>setContent(foobar, "application/x-foobar")</code>,
     * a DataContentHandler for "application/x-foobar" should be installed.
     * Refer to the Java Activation Framework for more information.
     *
     * @param o    the content object
     * @param type Mime type of the object
     * @throws IllegalWriteException if the underlying
     *                                  implementation does not support modification of
     *                                  existing values
     * @throws IllegalStateException if this message is
     *                                  obtained from a READ_ONLY folder.
     * @throws MessagingException    for other failures
     */
    @Override
    public void setContent(Object o, String type)
            throws MessagingException {
        if (o instanceof Multipart)
            setContent((Multipart) o);
        else
            setDataHandler(new DataHandler(o, type));
    }

    /**
     * Convenience method that sets the given String as this
     * part's content, with a MIME type of "text/plain". If the
     * string contains non US-ASCII characters. it will be encoded
     * using the platform's default charset. The charset is also
     * used to set the "charset" parameter.<p>
     *
     * Note that there may be a performance penalty if
     * <code>text</code> is large, since this method may have
     * to scan all the characters to determine what charset to
     * use. <p>
     *
     * If the charset is already known, use the
     * <code>setText</code> method that takes the charset parameter.
     *
     * @param text the text content to set
     * @throws MessagingException if an error occurs
     * @see #setText(String text, String charset)
     */
    @Override
    public void setText(String text) throws MessagingException {
        setText(text, null);
    }

    /**
     * Convenience method that sets the given String as this part's
     * content, with a MIME type of "text/plain" and the specified
     * charset. The given Unicode string will be charset-encoded
     * using the specified charset. The charset is also used to set
     * the "charset" parameter.
     *
     * @param text    the text content to set
     * @param charset the charset to use for the text
     * @throws MessagingException if an error occurs
     */
    @Override
    public void setText(String text, String charset)
            throws MessagingException {
        MimeBodyPart.setText(this, text, charset, "plain");
    }

    /**
     * Convenience method that sets the given String as this part's
     * content, with a primary MIME type of "text" and the specified
     * MIME subtype.  The given Unicode string will be charset-encoded
     * using the specified charset. The charset is also used to set
     * the "charset" parameter.
     *
     * @param text    the text content to set
     * @param charset the charset to use for the text
     * @param subtype the MIME subtype to use (e.g., "html")
     * @throws MessagingException if an error occurs
     * @since JavaMail 1.4
     */
    @Override
    public void setText(String text, String charset, String subtype)
            throws MessagingException {
        MimeBodyPart.setText(this, text, charset, subtype);
    }

    /**
     * This method sets the Message's content to a Multipart object.
     *
     * @param mp The multipart object that is the Message's content
     * @throws IllegalWriteException if the underlying
     *                                  implementation does not support modification of
     *                                  existing values
     * @throws IllegalStateException if this message is
     *                                  obtained from a READ_ONLY folder.
     * @throws MessagingException    for other failures
     */
    @Override
    public void setContent(Multipart mp) throws MessagingException {
        setDataHandler(new DataHandler(mp, mp.getContentType()));
        mp.setParent(this);
    }

    /**
     * Get a new Message suitable for a reply to this message.
     * The new Message will have its attributes and headers
     * set up appropriately.  Note that this new message object
     * will be empty, i.e., it will <strong>not</strong> have a "content".
     * These will have to be suitably filled in by the client. <p>
     *
     * If <code>replyToAll</code> is set, the new Message will be addressed
     * to all recipients of this message.  Otherwise, the reply will be
     * addressed to only the sender of this message (using the value
     * of the <code>getReplyTo</code> method).  <p>
     *
     * The "Subject" field is filled in with the original subject
     * prefixed with "Re:" (unless it already starts with "Re:").
     * The "In-Reply-To" header is set in the new message if this
     * message has a "Message-Id" header.  The <code>ANSWERED</code>
     * flag is set in this message.
     *
     * The current implementation also sets the "References" header
     * in the new message to include the contents of the "References"
     * header (or, if missing, the "In-Reply-To" header) in this message,
     * plus the contents of the "Message-Id" header of this message,
     * as described in RFC 2822.
     *
     * @param replyToAll reply should be sent to all recipients
     *                   of this message
     * @return the reply Message
     * @throws MessagingException for failures
     */
    @Override
    public Message reply(boolean replyToAll) throws MessagingException {
        return reply(replyToAll, true);
    }

    /**
     * Get a new Message suitable for a reply to this message.
     * The new Message will have its attributes and headers
     * set up appropriately.  Note that this new message object
     * will be empty, i.e., it will <strong>not</strong> have a "content".
     * These will have to be suitably filled in by the client. <p>
     *
     * If <code>replyToAll</code> is set, the new Message will be addressed
     * to all recipients of this message.  Otherwise, the reply will be
     * addressed to only the sender of this message (using the value
     * of the <code>getReplyTo</code> method).  <p>
     *
     * If <code>setAnswered</code> is set, the
     * {@link jakarta.mail.Flags.Flag#ANSWERED ANSWERED} flag is set
     * in this message. <p>
     *
     * The "Subject" field is filled in with the original subject
     * prefixed with "Re:" (unless it already starts with "Re:").
     * The "In-Reply-To" header is set in the new message if this
     * message has a "Message-Id" header.
     *
     * The current implementation also sets the "References" header
     * in the new message to include the contents of the "References"
     * header (or, if missing, the "In-Reply-To" header) in this message,
     * plus the contents of the "Message-Id" header of this message,
     * as described in RFC 2822.
     *
     * @param replyToAll  reply should be sent to all recipients
     *                    of this message
     * @param setAnswered set the ANSWERED flag in this message?
     * @return the reply Message
     * @throws MessagingException for failures
     * @since JavaMail 1.5
     */
    public Message reply(boolean replyToAll, boolean setAnswered)
            throws MessagingException {
        MimeMessage reply = createMimeMessage(session);
        /*
         * Have to manipulate the raw Subject header so that we don't lose
         * any encoding information.  This is safe because "Re:" isn't
         * internationalized and (generally) isn't encoded.  If the entire
         * Subject header is encoded, prefixing it with "Re: " still leaves
         * a valid and correct encoded header.
         */
        String subject = getHeader("Subject", null);
        if (subject != null) {
            if (!subject.regionMatches(true, 0, "Re: ", 0, 4))
                subject = "Re: " + subject;
            reply.setHeader("Subject", subject);
        }
        Address[] a = getReplyTo();
        reply.setRecipients(Message.RecipientType.TO, a);
        if (replyToAll) {
            List<Address> v = new ArrayList<>();
            // add my own address to list
            InternetAddress me = InternetAddress.getLocalAddress(session);
            if (me != null)
                v.add(me);
            // add any alternate names I'm known by
            String alternates = null;
            if (session != null)
                alternates = session.getProperty("mail.alternates");
            if (alternates != null)
                eliminateDuplicates(v,
                        InternetAddress.parse(alternates, false));
            // should we Cc all other original recipients?
            boolean replyallcc = false;
            if (session != null)
                replyallcc = MimeUtility.getBooleanProperty(
                        session.getProperties(),
                        "mail.replyallcc", false);
            // add the recipients from the To field so far
            eliminateDuplicates(v, a);
            a = getRecipients(Message.RecipientType.TO);
            a = eliminateDuplicates(v, a);
            if (a != null && a.length > 0) {
                if (replyallcc)
                    reply.addRecipients(Message.RecipientType.CC, a);
                else
                    reply.addRecipients(Message.RecipientType.TO, a);
            }
            a = getRecipients(Message.RecipientType.CC);
            a = eliminateDuplicates(v, a);
            if (a != null && a.length > 0)
                reply.addRecipients(Message.RecipientType.CC, a);
            // don't eliminate duplicate newsgroups
            a = getRecipients(RecipientType.NEWSGROUPS);
            if (a != null && a.length > 0)
                reply.setRecipients(RecipientType.NEWSGROUPS, a);
        }

        String msgId = getHeader("Message-Id", null);
        if (msgId != null)
            reply.setHeader("In-Reply-To", msgId);

        /*
         * Set the References header as described in RFC 2822:
         *
         * The "References:" field will contain the contents of the parent's
         * "References:" field (if any) followed by the contents of the parent's
         * "Message-ID:" field (if any).  If the parent message does not contain
         * a "References:" field but does have an "In-Reply-To:" field
         * containing a single message identifier, then the "References:" field
         * will contain the contents of the parent's "In-Reply-To:" field
         * followed by the contents of the parent's "Message-ID:" field (if
         * any).  If the parent has none of the "References:", "In-Reply-To:",
         * or "Message-ID:" fields, then the new message will have no
         * "References:" field.
         */
        String refs = getHeader("References", " ");
        if (refs == null) {
            // XXX - should only use if it contains a single message identifier
            refs = getHeader("In-Reply-To", " ");
        }
        if (msgId != null) {
            if (refs != null)
                refs = MimeUtility.unfold(refs) + " " + msgId;
            else
                refs = msgId;
        }
        if (refs != null)
            reply.setHeader("References", MimeUtility.fold(12, refs));

        if (setAnswered) {
            try {
                setFlags(answeredFlag, true);
            } catch (MessagingException mex) {
                // ignore it
            }
        }
        return reply;
    }

    // used above in reply()
    private static final Flags answeredFlag = new Flags(Flags.Flag.ANSWERED);

    /**
     * Check addrs for any duplicates that may already be in v.
     * Return a new array without the duplicates.  Add any new
     * addresses to v.  Note that the input array may be modified.
     */
    private Address[] eliminateDuplicates(List<Address> v, Address[] addrs) {
        if (addrs == null)
            return null;
        int gone = 0;
        for (int i = 0; i < addrs.length; i++) {
            boolean found = false;
            // search the list for this address
            for (int j = 0; j < v.size(); j++) {
                if (v.get(j).equals(addrs[i])) {
                    // found it; count it and remove it from the input array
                    found = true;
                    gone++;
                    addrs[i] = null;
                    break;
                }
            }
            if (!found)
                v.add(addrs[i]);    // add new address to list
        }
        // if we found any duplicates, squish the array
        if (gone != 0) {
            Address[] a;
            // new array should be same type as original array
            // XXX - there must be a better way, perhaps reflection?
            if (addrs instanceof InternetAddress[])
                a = new InternetAddress[addrs.length - gone];
            else
                a = new Address[addrs.length - gone];
            for (int i = 0, j = 0; i < addrs.length; i++)
                if (addrs[i] != null)
                    a[j++] = addrs[i];
            addrs = a;
        }
        return addrs;
    }

    /**
     * Output the message as an RFC 822 format stream. <p>
     *
     * Note that, depending on how the messag was constructed, it may
     * use a variety of line termination conventions.  Generally the
     * output should be sent through an appropriate FilterOutputStream
     * that converts the line terminators to the desired form, either
     * CRLF for MIME compatibility and for use in Internet protocols,
     * or the local platform's line terminator for storage in a local
     * text file. <p>
     *
     * This implementation calls the <code>writeTo(OutputStream,
     * String[])</code> method with a null ignore list.
     *
     * @throws IOException        if an error occurs writing to the stream
     *                               or if an error is generated by the
     *                               jakarta.activation layer.
     * @throws MessagingException for other failures
     * @see jakarta.activation.DataHandler#writeTo
     */
    @Override
    public void writeTo(OutputStream os)
            throws IOException, MessagingException {
        writeTo(os, null);
    }

    /**
     * Output the message as an RFC 822 format stream, without
     * specified headers.  If the <code>saved</code> flag is not set,
     * the <code>saveChanges</code> method is called.
     * If the <code>modified</code> flag is not
     * set and the <code>content</code> array is not null, the
     * <code>content</code> array is written directly, after
     * writing the appropriate message headers.
     *
     * @param os         the stream to write to
     * @param ignoreList the headers to not include in the output
     * @throws IOException                     if an error occurs writing to the stream
     *                                            or if an error is generated by the
     *                                            jakarta.activation layer.
     * @throws jakarta.mail.MessagingException for other failures
     * @see jakarta.activation.DataHandler#writeTo
     */
    public void writeTo(OutputStream os, String[] ignoreList)
            throws IOException, MessagingException {
        if (!saved)
            saveChanges();

        if (modified) {
            MimeBodyPart.writeTo(this, os, ignoreList);
            return;
        }

        // Else, the content is untouched, so we can just output it
        // First, write out the header
        Enumeration<String> hdrLines = getNonMatchingHeaderLines(ignoreList);
        LineOutputStream los = provider().outputLineStream(os, allowutf8);
        while (hdrLines.hasMoreElements())
            los.writeln(hdrLines.nextElement());

        // The CRLF separator between header and content
        los.writeln();

        // Finally, the content.
        if (content == null) {
            // call getContentStream to give subclass a chance to
            // provide the data on demand
            InputStream is = null;
            byte[] buf = new byte[8192];
            try {
                is = getContentStream();
                // now copy the data to the output stream
                int len;
                while ((len = is.read(buf)) > 0)
                    os.write(buf, 0, len);
            } finally {
                if (is != null)
                    is.close();
                buf = null;
            }
        } else {
            os.write(content);
        }
        os.flush();
    }

    /**
     * Get all the headers for this header_name. Note that certain
     * headers may be encoded as per RFC 2047 if they contain
     * non US-ASCII characters and these should be decoded. <p>
     *
     * This implementation obtains the headers from the
     * <code>headers</code> InternetHeaders object.
     *
     * @param name name of header
     * @return array of headers
     * @throws MessagingException for failures
     * @see jakarta.mail.internet.MimeUtility
     */
    @Override
    public String[] getHeader(String name)
            throws MessagingException {
        return headers.getHeader(name);
    }

    /**
     * Get all the headers for this header name, returned as a single
     * String, with headers separated by the delimiter. If the
     * delimiter is <code>null</code>, only the first header is
     * returned.
     *
     * @param name      the name of this header
     * @param delimiter separator between values
     * @return the value fields for all headers with
     * this name
     * @throws MessagingException for failures
     */
    @Override
    public String getHeader(String name, String delimiter)
            throws MessagingException {
        return headers.getHeader(name, delimiter);
    }

    /**
     * Set the value for this header_name. Replaces all existing
     * header values with this new value. Note that RFC 822 headers
     * must contain only US-ASCII characters, so a header that
     * contains non US-ASCII characters must have been encoded by the
     * caller as per the rules of RFC 2047.
     *
     * @param name  header name
     * @param value header value
     * @throws IllegalWriteException if the underlying
     *                                  implementation does not support modification
     * @throws IllegalStateException if this message is
     *                                  obtained from a READ_ONLY folder.
     * @throws MessagingException    for other failures
     * @see jakarta.mail.internet.MimeUtility
     */
    @Override
    public void setHeader(String name, String value)
            throws MessagingException {
        headers.setHeader(name, value);
    }

    /**
     * Add this value to the existing values for this header_name.
     * Note that RFC 822 headers must contain only US-ASCII
     * characters, so a header that contains non US-ASCII characters
     * must have been encoded as per the rules of RFC 2047.
     *
     * @param name  header name
     * @param value header value
     * @throws IllegalWriteException if the underlying
     *                                  implementation does not support modification
     * @throws IllegalStateException if this message is
     *                                  obtained from a READ_ONLY folder.
     * @throws MessagingException    for other failures
     * @see jakarta.mail.internet.MimeUtility
     */
    @Override
    public void addHeader(String name, String value)
            throws MessagingException {
        headers.addHeader(name, value);
    }

    /**
     * Remove all headers with this name.
     *
     * @throws IllegalWriteException if the underlying
     *                                  implementation does not support modification
     * @throws IllegalStateException if this message is
     *                                  obtained from a READ_ONLY folder.
     * @throws MessagingException    for other failures
     */
    @Override
    public void removeHeader(String name)
            throws MessagingException {
        headers.removeHeader(name);
    }

    /**
     * Return all the headers from this Message as an enumeration
     * of Header objects. <p>
     *
     * Note that certain headers may be encoded as per RFC 2047
     * if they contain non US-ASCII characters and these should
     * be decoded. <p>
     *
     * This implementation obtains the headers from the
     * <code>headers</code> InternetHeaders object.
     *
     * @return array of header objects
     * @throws MessagingException for failures
     * @see jakarta.mail.internet.MimeUtility
     */
    @Override
    public Enumeration<Header> getAllHeaders() throws MessagingException {
        return headers.getAllHeaders();
    }

    /**
     * Return matching headers from this Message as an Enumeration of
     * Header objects. This implementation obtains the headers from
     * the <code>headers</code> InternetHeaders object.
     *
     * @throws MessagingException for failures
     */
    @Override
    public Enumeration<Header> getMatchingHeaders(String[] names)
            throws MessagingException {
        return headers.getMatchingHeaders(names);
    }

    /**
     * Return non-matching headers from this Message as an
     * Enumeration of Header objects. This implementation
     * obtains the header from the <code>headers</code> InternetHeaders object.
     *
     * @throws MessagingException for failures
     */
    @Override
    public Enumeration<Header> getNonMatchingHeaders(String[] names)
            throws MessagingException {
        return headers.getNonMatchingHeaders(names);
    }

    /**
     * Add a raw RFC 822 header-line.
     *
     * @throws IllegalWriteException if the underlying
     *                                  implementation does not support modification
     * @throws IllegalStateException if this message is
     *                                  obtained from a READ_ONLY folder.
     * @throws MessagingException    for other failures
     */
    @Override
    public void addHeaderLine(String line) throws MessagingException {
        headers.addHeaderLine(line);
    }

    /**
     * Get all header lines as an Enumeration of Strings. A Header
     * line is a raw RFC 822 header-line, containing both the "name"
     * and "value" field.
     *
     * @throws MessagingException for failures
     */
    @Override
    public Enumeration<String> getAllHeaderLines() throws MessagingException {
        return headers.getAllHeaderLines();
    }

    /**
     * Get matching header lines as an Enumeration of Strings.
     * A Header line is a raw RFC 822 header-line, containing both
     * the "name" and "value" field.
     *
     * @throws MessagingException for failures
     */
    @Override
    public Enumeration<String> getMatchingHeaderLines(String[] names)
            throws MessagingException {
        return headers.getMatchingHeaderLines(names);
    }

    /**
     * Get non-matching header lines as an Enumeration of Strings.
     * A Header line is a raw RFC 822 header-line, containing both
     * the "name" and "value" field.
     *
     * @throws MessagingException for failures
     */
    @Override
    public Enumeration<String> getNonMatchingHeaderLines(String[] names)
            throws MessagingException {
        return headers.getNonMatchingHeaderLines(names);
    }

    /**
     * Return a <code>Flags</code> object containing the flags for
     * this message. <p>
     *
     * Note that a clone of the internal Flags object is returned, so
     * modifying the returned Flags object will not affect the flags
     * of this message.
     *
     * @return Flags object containing the flags for this message
     * @throws MessagingException for failures
     * @see jakarta.mail.Flags
     */
    @Override
    public synchronized Flags getFlags() throws MessagingException {
        return (Flags) flags.clone();
    }

    /**
     * Check whether the flag specified in the <code>flag</code>
     * argument is set in this message. <p>
     *
     * This implementation checks this message's internal
     * <code>flags</code> object.
     *
     * @param flag the flag
     * @return value of the specified flag for this message
     * @throws MessagingException for failures
     * @see jakarta.mail.Flags.Flag#ANSWERED
     * @see jakarta.mail.Flags.Flag#DELETED
     * @see jakarta.mail.Flags.Flag#DRAFT
     * @see jakarta.mail.Flags.Flag#FLAGGED
     * @see jakarta.mail.Flags.Flag#RECENT
     * @see jakarta.mail.Flags.Flag#SEEN
     * @see jakarta.mail.Flags.Flag
     */
    @Override
    public synchronized boolean isSet(Flags.Flag flag)
            throws MessagingException {
        return (flags.contains(flag));
    }

    /**
     * Set the flags for this message. <p>
     *
     * This implementation modifies the <code>flags</code> field.
     *
     * @throws IllegalWriteException if the underlying
     *                                  implementation does not support modification
     * @throws IllegalStateException if this message is
     *                                  obtained from a READ_ONLY folder.
     * @throws MessagingException    for other failures
     */
    @Override
    public synchronized void setFlags(Flags flag, boolean set)
            throws MessagingException {
        if (set)
            flags.add(flag);
        else
            flags.remove(flag);
    }

    /**
     * Updates the appropriate header fields of this message to be
     * consistent with the message's contents. If this message is
     * contained in a Folder, any changes made to this message are
     * committed to the containing folder. <p>
     *
     * If any part of a message's headers or contents are changed,
     * <code>saveChanges</code> must be called to ensure that those
     * changes are permanent. Otherwise, any such modifications may or
     * may not be saved, depending on the folder implementation. <p>
     *
     * Messages obtained from folders opened READ_ONLY should not be
     * modified and saveChanges should not be called on such messages. <p>
     *
     * This method sets the <code>modified</code> flag to true, the
     * <code>save</code> flag to true, and then calls the
     * <code>updateHeaders</code> method.
     *
     * @throws IllegalWriteException if the underlying
     *                                  implementation does not support modification
     * @throws IllegalStateException if this message is
     *                                  obtained from a READ_ONLY folder.
     * @throws MessagingException    for other failures
     */
    @Override
    public void saveChanges() throws MessagingException {
        modified = true;
        saved = true;
        updateHeaders();
    }

    /**
     * Update the Message-ID header.  This method is called
     * by the <code>updateHeaders</code> and allows a subclass
     * to override only the algorithm for choosing a Message-ID.
     *
     * @throws MessagingException for failures
     * @since JavaMail 1.4
     */
    protected void updateMessageID() throws MessagingException {
        setHeader("Message-ID",
                "<" + UniqueValue.getUniqueMessageIDValue(session) + ">");

    }

    /**
     * Called by the <code>saveChanges</code> method to actually
     * update the MIME headers.  The implementation here sets the
     * <code>Content-Transfer-Encoding</code> header (if needed
     * and not already set), the <code>Date</code> header (if
     * not already set), the <code>MIME-Version</code> header
     * and the <code>Message-ID</code> header. Also, if the content
     * of this message is a <code>MimeMultipart</code>, its
     * <code>updateHeaders</code> method is called. <p>
     *
     * If the {@link #cachedContent} field is not null (that is,
     * it references a Multipart or Message object), then
     * that object is used to set a new DataHandler, any
     * stream data used to create this object is discarded,
     * and the {@link #cachedContent} field is cleared.
     *
     * @throws IllegalWriteException if the underlying
     *                                  implementation does not support modification
     * @throws IllegalStateException if this message is
     *                                  obtained from a READ_ONLY folder.
     * @throws MessagingException    for other failures
     */
    protected synchronized void updateHeaders() throws MessagingException {
        MimeBodyPart.updateHeaders(this);
        setHeader("MIME-Version", "1.0");
        if (getHeader("Date") == null)
            setSentDate(new Date());
        updateMessageID();

        if (cachedContent != null) {
            dh = new DataHandler(cachedContent, getContentType());
            cachedContent = null;
            content = null;
            if (contentStream != null) {
                try {
                    contentStream.close();
                } catch (IOException ioex) {
                }    // nothing to do
            }
            contentStream = null;
        }
    }

    /**
     * Create and return an InternetHeaders object that loads the
     * headers from the given InputStream.  Subclasses can override
     * this method to return a subclass of InternetHeaders, if
     * necessary.  This implementation simply constructs and returns
     * an InternetHeaders object.
     *
     * @param is the InputStream to read the headers from
     * @return an InternetHeaders object
     * @throws MessagingException for failures
     * @since JavaMail 1.2
     */
    protected InternetHeaders createInternetHeaders(InputStream is)
            throws MessagingException {
        return new InternetHeaders(is, allowutf8);
    }

    /**
     * Create and return a MimeMessage object.  The reply method
     * uses this method to create the MimeMessage object that it
     * will return.  Subclasses can override this method to return
     * a subclass of MimeMessage.  This implementation simply constructs
     * and returns a MimeMessage object using the supplied Session.
     *
     * @param session the Session to use for the new message
     * @return the new MimeMessage object
     * @throws MessagingException for failures
     * @since JavaMail 1.4
     */
    protected MimeMessage createMimeMessage(Session session)
            throws MessagingException {
        return new MimeMessage(session);
    }

    private StreamProvider provider() throws MessagingException {
        try {
            try {
                final Session s = this.session;
                if (s != null) {
                    return s.getStreamProvider();
                } else {
                    return Session.getDefaultInstance(System.getProperties(),
                        null).getStreamProvider();
                }
            } catch (ServiceConfigurationError sce) {
                throw new IllegalStateException(sce);
            }
        } catch (RuntimeException re) {
            throw new MessagingException("Unable to get "
                    + StreamProvider.class.getName(), re);
        }
    }

    boolean isStrict() {
        return strict;
    }

    boolean isAllowutf8() {
        return allowutf8;
    }

}
