FileDocCategorySizeDatePackage
MimeMessage.javaAPI DocGlassfish v2 API76761Wed May 23 10:57:54 BST 2007javax.mail.internet

MimeMessage

public class MimeMessage extends Message implements MimePart
This class represents a MIME style email message. It implements the Message abstract class and the MimePart interface.

Clients wanting to create new MIME style messages will instantiate an empty MimeMessage object and then fill it with appropriate attributes and content.

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.

MimeMessage uses the InternetHeaders class to parse and store the top level RFC 822 headers of a message.

The mail.mime.address.strict session property controls the parsing of address headers. By default, strict parsing of address headers is done. If this property is set to "false", strict parsing is not done and many illegal addresses that sometimes occur in real messages are allowed. See the InternetAddress class for details.


A note on RFC 822 and MIME headers

RFC 822 header fields must 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 setHeader, addHeader, and addHeaderLine 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
javax.mail.internet.MimeUtility
see
javax.mail.Part
see
javax.mail.Message
see
javax.mail.internet.MimePart
see
javax.mail.internet.InternetAddress

Fields Summary
protected DataHandler
dh
The DataHandler object representing this Message's content.
protected byte[]
content
Byte array that holds the bytes of this Message's content.
protected InputStream
contentStream
If the data for this message was supplied by an InputStream that implements the SharedInputStream interface, contentStream is another such stream representing the content of this message. In this case, content will be null.
protected InternetHeaders
headers
The InternetHeaders object that stores the header of this message.
protected Flags
flags
The Flags for this message.
protected boolean
modified
A flag indicating whether the message has been modified. If the message has not been modified, any data in the content array is assumed to be valid and is used directly in the writeTo method. This flag is set to true when an empty message is created or when the saveChanges method is called.
protected boolean
saved
Does the saveChanges method need to be called on this message? This flag is set to false by the public constructor and set to true by the saveChanges method. The writeTo method checks this flag and calls the saveChanges method as necessary. This avoids the common mistake of forgetting to call the saveChanges method on a newly constructed message.
Object
cachedContent
If our content is a Multipart of 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. XXX - must have package access for MimeBodyPart.updateHeaders
private static MailDateFormat
mailDateFormat
private boolean
strict
private static final Flags
answeredFlag
Constructors Summary
public MimeMessage(Session session)
Default constructor. An empty message object is created. The headers field is set to an empty InternetHeaders object. The flags field is set to an empty Flags object. The modified flag is set to true.


                                            
       
	super(session);
	modified = true;
	headers = new InternetHeaders();
	flags = new Flags();	// empty flags object
	initStrict();
    
public MimeMessage(Session session, InputStream is)
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.

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
exception
MessagingException

	super(session);
	flags = new Flags(); // empty Flags object
	initStrict();
	parse(is);
	saved = true;
    
public MimeMessage(MimeMessage source)
Constructs a new MimeMessage with content initialized from the source MimeMessage. The new message is independent of the original.

Note: The current implementation is rather inefficient, copying the data more times than strictly necessary.

param
source the message to copy content from
exception
MessagingException
since
JavaMail 1.2

	super(source.session);
	flags = source.getFlags();
	ByteArrayOutputStream bos;
	int size = source.getSize();
	if (size > 0)
	    bos = new ByteArrayOutputStream(size);
	else
	    bos = new ByteArrayOutputStream();
	try {
	    strict = source.strict;
	    source.writeTo(bos);
	    bos.close();
	    SharedByteArrayInputStream bis =
			    new SharedByteArrayInputStream(bos.toByteArray());
	    parse(bis);
	    bis.close();
	    saved = true;
	} catch (IOException ex) {
	    // should never happen, but just in case...
	    throw new MessagingException("IOException while copying message",
					    ex);
	}
    
protected MimeMessage(Folder folder, int msgnum)
Constructs an empty MimeMessage object with the given Folder and message number.

This method is for providers subclassing MimeMessage.

	super(folder, msgnum);
	flags = new Flags();  // empty Flags object
	saved = true;
	initStrict();
    
protected MimeMessage(Folder folder, InputStream is, int msgnum)
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.

This method is for providers subclassing MimeMessage.

param
folder The containing folder.
param
is the message input stream
param
msgnum Message number of this message within its folder
exception
MessagingException

	this(folder, msgnum);
	initStrict();
	parse(is);
    
protected MimeMessage(Folder folder, InternetHeaders headers, byte[] content, int msgnum)
Constructs a MimeMessage from the given InternetHeaders object and content. This method is for providers subclassing MimeMessage.

param
folder The containing folder.
param
headers The headers
param
content The message content
param
msgnum Message number of this message within its folder
exception
MessagingException

	this(folder, msgnum);
	this.headers = headers;
	this.content = content;
	initStrict();
    
Methods Summary
private voidaddAddressHeader(java.lang.String name, javax.mail.Address[] addresses)

	String s = InternetAddress.toString(addresses);
	if (s == null)
	    return;
	addHeader(name, s);
    
public voidaddFrom(javax.mail.Address[] addresses)
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
exception
IllegalWriteException if the underlying implementation does not support modification of existing values
exception
IllegalStateException if this message is obtained from a READ_ONLY folder.
exception
MessagingException

	addAddressHeader("From", addresses);
    
public voidaddHeader(java.lang.String name, java.lang.String 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
see
javax.mail.internet.MimeUtility
exception
IllegalWriteException if the underlying implementation does not support modification
exception
IllegalStateException if this message is obtained from a READ_ONLY folder.
exception
MessagingException

	headers.addHeader(name, value);
    
public voidaddHeaderLine(java.lang.String line)
Add a raw RFC 822 header-line.

exception
IllegalWriteException if the underlying implementation does not support modification
exception
IllegalStateException if this message is obtained from a READ_ONLY folder.
exception
MessagingException

	headers.addHeaderLine(line);
    
public voidaddRecipients(javax.mail.Message$RecipientType type, javax.mail.Address[] addresses)
Add the given addresses to the specified recipient type.

param
type Recipient type
param
addresses Addresses
exception
IllegalWriteException if the underlying implementation does not support modification of existing values
exception
IllegalStateException if this message is obtained from a READ_ONLY folder.
exception
MessagingException

	if (type == RecipientType.NEWSGROUPS) {
	    String s = NewsAddress.toString(addresses);
	    if (s != null)
		addHeader("Newsgroups", s);
	} else
	    addAddressHeader(getHeaderName(type), addresses);
    
public voidaddRecipients(javax.mail.Message$RecipientType type, java.lang.String addresses)
Add the given addresses to the specified recipient type.

param
type Recipient type
param
addresses Addresses
exception
AddressException if the attempt to parse the addresses String fails
exception
IllegalWriteException if the underlying implementation does not support modification of existing values
exception
IllegalStateException if this message is obtained from a READ_ONLY folder.
exception
MessagingException
since
JavaMail 1.2

        if (type == RecipientType.NEWSGROUPS) {
            if (addresses != null && addresses.length() != 0)
                addHeader("Newsgroups", addresses);
        } else
            addAddressHeader(getHeaderName(type), InternetAddress.parse(addresses));
    
protected javax.mail.internet.InternetHeaderscreateInternetHeaders(java.io.InputStream is)
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
exception
MessagingException
since
JavaMail 1.2

	return new InternetHeaders(is);
    
protected javax.mail.internet.MimeMessagecreateMimeMessage(javax.mail.Session session)
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
since
JavaMail 1.4

	return new MimeMessage(session);
    
private javax.mail.Address[]eliminateDuplicates(java.util.Vector v, javax.mail.Address[] addrs)
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.


                                           
          
	if (addrs == null)
	    return null;
	int gone = 0;
	for (int i = 0; i < addrs.length; i++) {
	    boolean found = false;
	    // search the vector for this address
	    for (int j = 0; j < v.size(); j++) {
		if (((InternetAddress)v.elementAt(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.addElement(addrs[i]);	// add new address to vector
	}
	// 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;
    
private javax.mail.Address[]getAddressHeader(java.lang.String name)

	String s = getHeader(name, ",");
	return (s == null) ? null : InternetAddress.parseHeader(s, strict);
    
public java.util.EnumerationgetAllHeaderLines()
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.

exception
MessagingException

	return headers.getAllHeaderLines();
    
public java.util.EnumerationgetAllHeaders()
Return all the headers from this Message as an enumeration of Header objects.

Note that certain headers may be encoded as per RFC 2047 if they contain non US-ASCII characters and these should be decoded.

This implementation obtains the headers from the headers InternetHeaders object.

return
array of header objects
exception
MessagingException
see
javax.mail.internet.MimeUtility

	return headers.getAllHeaders();	
    
public javax.mail.Address[]getAllRecipients()
Get all the recipient addresses for the message. Extracts the TO, CC, BCC, and NEWSGROUPS recipients.

return
array of Address objects
exception
MessagingException
see
javax.mail.Message.RecipientType#TO
see
javax.mail.Message.RecipientType#CC
see
javax.mail.Message.RecipientType#BCC
see
javax.mail.internet.MimeMessage.RecipientType#NEWSGROUPS

	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;
    
public java.lang.ObjectgetContent()
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.

This implementation obtains the content from the DataHandler, that is, it invokes getDataHandler().getContent(). 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
see
javax.mail.Part
see
javax.activation.DataHandler#getContent
exception
MessagingException
exception
IOException this is typically thrown by the DataHandler. Refer to the documentation for javax.activation.DataHandler for more details.

	if (cachedContent != null)
	    return cachedContent;
	Object c;
	try {
	    c = getDataHandler().getContent();
	} catch (FolderClosedIOException fex) {
	    throw new FolderClosedException(fex.getFolder(), fex.getMessage());
	} catch (MessageRemovedIOException mex) {
	    throw new MessageRemovedException(mex.getMessage());
	}
	if (MimeBodyPart.cacheMultipart &&
		(c instanceof Multipart || c instanceof Message) &&
		(content != null || contentStream != null)) {
	    cachedContent = c;
	}
	return c;
    
public java.lang.StringgetContentID()
Returns the value of the "Content-ID" header field. Returns null if the field is unavailable or its value is absent.

This implementation uses the getHeader method to obtain the requisite header field.

return
content-ID
exception
MessagingException

	return getHeader("Content-Id", null);
    
public java.lang.String[]getContentLanguage()
Get the languages specified in the "Content-Language" header field of this message. The Content-Language header is defined by RFC 1766. Returns null if this field is unavailable or its value is absent.

This implementation uses the getHeader method to obtain the requisite header field.

return
value of content-language header.
exception
MessagingException

	return MimeBodyPart.getContentLanguage(this);
    
public java.lang.StringgetContentMD5()
Return the value of the "Content-MD5" header field. Returns null if this field is unavailable or its value is absent.

This implementation uses the getHeader method to obtain the requisite header field.

return
content-MD5
exception
MessagingException

	return getHeader("Content-MD5", null);
    
protected java.io.InputStreamgetContentStream()
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.

This implementation returns a SharedInputStream, if contentStream is not null. Otherwise, it returns a ByteArrayInputStream constructed out of the content byte array.

see
#content

	if (contentStream != null)
	    return ((SharedInputStream)contentStream).newStream(0, -1);
	if (content != null)
	    return new SharedByteArrayInputStream(content);

	throw new MessagingException("No content");
    
public java.lang.StringgetContentType()
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.

This implementation uses the getHeader method to obtain the requisite header field.

return
The ContentType of this part
exception
MessagingException
see
javax.activation.DataHandler

	String s = getHeader("Content-Type", null);
	if (s == null)
	    return "text/plain";
	return s;
    
public synchronized javax.activation.DataHandlergetDataHandler()
Return a DataHandler for this Message's content.

The implementation provided here works as follows. Note the use of the getContentStream method to generate the byte stream for the content. Also note that any transfer-decoding is done automatically within this method.

getDataHandler() {
if (dh == null) {
dh = new DataHandler(new MimePartDataSource(this));
}
return dh;
}

class MimePartDataSource implements DataSource { public getInputStream() { return MimeUtility.decode( getContentStream(), getEncoding()); } .... }

exception
MessagingException

	if (dh == null)
	    dh = new DataHandler(new MimePartDataSource(this));
	return dh;
    
public java.lang.StringgetDescription()
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.

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

This implementation uses the getHeader method to obtain the requisite header field.

return
content-description
exception
MessagingException

	return MimeBodyPart.getDescription(this);
    
public java.lang.StringgetDisposition()
Returns the value of the "Content-Disposition" header field. This represents the disposition of this part. The disposition describes how the part should be presented to the user.

If the Content-Disposition field is unavailable, null is returned.

This implementation uses the getHeader method to obtain the requisite header field.

return
disposition of this part, or null if unknown
exception
MessagingException

	return MimeBodyPart.getDisposition(this);
    
public java.lang.StringgetEncoding()
Returns the content transfer encoding from the "Content-Transfer-Encoding" header field. Returns null if the header is unavailable or its value is absent.

This implementation uses the getHeader method to obtain the requisite header field.

return
content-transfer-encoding
exception
MessagingException

	return MimeBodyPart.getEncoding(this);
    
public java.lang.StringgetFileName()
Get the filename associated with this Message.

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 null if both are absent.

If the mail.mime.encodefilename 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
exception
MessagingException

	return MimeBodyPart.getFileName(this);
    
public synchronized javax.mail.FlagsgetFlags()
Return a Flags object containing the flags for this message.

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
exception
MessagingException
see
javax.mail.Flags

	return (Flags)flags.clone();
    
public javax.mail.Address[]getFrom()
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, null is returned.

This implementation uses the getHeader method to obtain the requisite header field.

return
Address object
exception
MessagingException
see
#headers

	Address[] a = getAddressHeader("From");
	if (a == null)
	    a = getAddressHeader("Sender");
	
	return a;
    
public java.lang.String[]getHeader(java.lang.String name)
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.

This implementation obtains the headers from the headers InternetHeaders object.

param
name name of header
return
array of headers
exception
MessagingException
see
javax.mail.internet.MimeUtility

	return headers.getHeader(name);
    
public java.lang.StringgetHeader(java.lang.String name, java.lang.String delimiter)
Get all the headers for this header name, returned as a single String, with headers separated by the delimiter. If the delimiter is null, 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
exception
MessagingException

	return headers.getHeader(name, delimiter);
    
private java.lang.StringgetHeaderName(javax.mail.Message$RecipientType type)

	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;
    
public java.io.InputStreamgetInputStream()
Return a decoded input stream for this Message's "content".

This implementation obtains the input stream from the DataHandler, that is, it invokes getDataHandler().getInputStream().

return
an InputStream
exception
MessagingException
exception
IOException this is typically thrown by the DataHandler. Refer to the documentation for javax.activation.DataHandler for more details.
see
#getContentStream
see
javax.activation.DataHandler#getInputStream

	return getDataHandler().getInputStream();
    
public intgetLineCount()
Return the number of lines for the content of this message. Return -1 if this number cannot be determined.

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.

This implementation returns -1.

return
number of lines in the content.
exception
MessagingException

	return -1;
     
public java.util.EnumerationgetMatchingHeaderLines(java.lang.String[] names)
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.

exception
MessagingException

	return headers.getMatchingHeaderLines(names);
    
public java.util.EnumerationgetMatchingHeaders(java.lang.String[] names)
Return matching headers from this Message as an Enumeration of Header objects. This implementation obtains the headers from the headers InternetHeaders object.

exception
MessagingException

	return headers.getMatchingHeaders(names);
    
public java.lang.StringgetMessageID()
Returns the value of the "Message-ID" header field. Returns null if this field is unavailable or its value is absent.

The default implementation provided here uses the getHeader method to return the value of the "Message-ID" field.

return
Message-ID
exception
MessagingException if the retrieval of this field causes any exception.
see
javax.mail.search.MessageIDTerm
since
JavaMail 1.1

	return getHeader("Message-ID", null);
    
public java.util.EnumerationgetNonMatchingHeaderLines(java.lang.String[] 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.

exception
MessagingException

	return headers.getNonMatchingHeaderLines(names);
    
public java.util.EnumerationgetNonMatchingHeaders(java.lang.String[] names)
Return non-matching headers from this Message as an Enumeration of Header objects. This implementation obtains the header from the headers InternetHeaders object.

exception
MessagingException

	return headers.getNonMatchingHeaders(names);
    
public java.io.InputStreamgetRawInputStream()
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 getInputStream method or getContent method from returning the correct data. In such a case the application may use this method and attempt to decode the raw data itself.

This implementation simply calls the getContentStream method.

see
#getInputStream
see
#getContentStream
since
JavaMail 1.2

	return getContentStream();
    
public java.util.DategetReceivedDate()
Returns the Date on this message was received. Returns null if this date cannot be obtained.

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.

This implementation returns null.

return
the date this message was received
exception
MessagingException

	return null;	
    
public javax.mail.Address[]getRecipients(javax.mail.Message$RecipientType type)
Returns the recepients specified by the type. The mapping between the type and the corresponding RFC 822 header is as follows:
Message.RecipientType.TO "To"
Message.RecipientType.CC "Cc"
Message.RecipientType.BCC "Bcc"
MimeMessage.RecipientType.NEWSGROUPS "Newsgroups"

Returns null if the header specified by the type is not found or if its value is empty.

This implementation uses the getHeader method to obtain the requisite header field.

param
type Type of recepient
return
array of Address objects
exception
MessagingException if header could not be retrieved
exception
AddressException if the header is misformatted
see
#headers
see
javax.mail.Message.RecipientType#TO
see
javax.mail.Message.RecipientType#CC
see
javax.mail.Message.RecipientType#BCC
see
javax.mail.internet.MimeMessage.RecipientType#NEWSGROUPS

	if (type == RecipientType.NEWSGROUPS) {
	    String s = getHeader("Newsgroups", ",");
	    return (s == null) ? null : NewsAddress.parse(s);
	} else
	    return getAddressHeader(getHeaderName(type));
    
public javax.mail.Address[]getReplyTo()
Return the value of the RFC 822 "Reply-To" header field. If this header is unavailable or its value is absent, then the getFrom method is called and its value is returned. This implementation uses the getHeader method to obtain the requisite header field.

exception
MessagingException
see
#headers

	Address[] a = getAddressHeader("Reply-To");
	if (a == null)
	    a = getFrom();
	return a;
    
public javax.mail.AddressgetSender()
Returns the value of the RFC 822 "Sender" header field. If the "Sender" header field is absent, null is returned.

This implementation uses the getHeader method to obtain the requisite header field.

return
Address object
exception
MessagingException
see
#headers
since
JavaMail 1.3

	Address[] a = getAddressHeader("Sender");
	if (a == null || a.length == 0)
	    return null;
	return a[0];	// there can be only one
    
public java.util.DategetSentDate()
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.

This implementation uses the getHeader method to obtain the requisite header field.

return
The sent Date
exception
MessagingException

	String s = getHeader("Date", null);
	if (s != null) {
	    try {
		synchronized (mailDateFormat) {
		    return mailDateFormat.parse(s);
		}
	    } catch (ParseException pex) {
		return null;
	    }
	}
	
	return null;
    
public intgetSize()
Return the size of the content of this message in bytes. Return -1 if the size cannot be determined.

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.

This implementation returns the size of the content array (if not null), or, if contentStream is not null, and the available method returns a positive number, it returns that number as the size. Otherwise, it returns -1.

return
size of content in bytes
exception
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;
    
public java.lang.StringgetSubject()
Returns the value of the "Subject" header field. Returns null if the subject field is unavailable or its value is absent.

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.

This implementation uses the getHeader method to obtain the requisite header field.

return
Subject
exception
MessagingException
see
#headers

	String rawvalue = getHeader("Subject", null);

	if (rawvalue == null)
	    return null;

	try {
	    return MimeUtility.decodeText(MimeUtility.unfold(rawvalue));
	} catch (UnsupportedEncodingException ex) {
	    return rawvalue;
	}
    
private voidinitStrict()
Set the strict flag based on property.

	if (session != null) {
	    String s = session.getProperty("mail.mime.address.strict");
	    strict = s == null || !s.equalsIgnoreCase("false");
	}
    
public booleanisMimeType(java.lang.String mimeType)
Is this Part of the specified MIME type? This method compares only the primaryType and subType. The parameters of the content types are ignored.

For example, this method will return true when comparing a Part of content type "text/plain" with "text/plain; charset=foobar".

If the subType of mimeType is the special character '*', then the subtype is ignored during the comparison.

	return MimeBodyPart.isMimeType(this, mimeType);
    
public synchronized booleanisSet(javax.mail.Flags$Flag flag)
Check whether the flag specified in the flag argument is set in this message.

This implementation checks this message's internal flags object.

param
flag the flag
return
value of the specified flag for this message
see
javax.mail.Flags.Flag
see
javax.mail.Flags.Flag#ANSWERED
see
javax.mail.Flags.Flag#DELETED
see
javax.mail.Flags.Flag#DRAFT
see
javax.mail.Flags.Flag#FLAGGED
see
javax.mail.Flags.Flag#RECENT
see
javax.mail.Flags.Flag#SEEN
exception
MessagingException

	return (flags.contains(flag));
    
protected voidparse(java.io.InputStream is)
Parse the InputStream setting the headers and content fields appropriately. Also resets the modified flag.

This method is intended for use by subclasses that need to control when the InputStream is parsed.

param
is The message input stream
exception
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 = ASCIIUtility.getBytes(is);
	    } catch (IOException ioex) {
		throw new MessagingException("IOException", ioex);
	    }
	}

	modified = false;
    
public voidremoveHeader(java.lang.String name)
Remove all headers with this name.

exception
IllegalWriteException if the underlying implementation does not support modification
exception
IllegalStateException if this message is obtained from a READ_ONLY folder.
exception
MessagingException

	headers.removeHeader(name);
    
public Messagereply(boolean replyToAll)
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 not have a "content". These will have to be suitably filled in by the client.

If replyToAll 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 getReplyTo method).

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 ANSWERED 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
exception
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) {
	    Vector v = new Vector();
	    // add my own address to list
	    InternetAddress me = InternetAddress.getLocalAddress(session);
	    if (me != null)
		v.addElement(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?
	    String replyallccStr = null;
	    if (session != null)
		replyallccStr = session.getProperty("mail.replyallcc");
	    boolean replyallcc =
		replyallccStr != null && replyallccStr.equalsIgnoreCase("true");
	    // 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));

	try {
	    setFlags(answeredFlag, true);
	} catch (MessagingException mex) {
	    // ignore it
	}
	return reply;
    
public voidsaveChanges()
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.

If any part of a message's headers or contents are changed, saveChanges 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.

Messages obtained from folders opened READ_ONLY should not be modified and saveChanges should not be called on such messages.

This method sets the modified flag to true, the save flag to true, and then calls the updateHeaders method.

exception
IllegalWriteException if the underlying implementation does not support modification
exception
IllegalStateException if this message is obtained from a READ_ONLY folder.
exception
MessagingException

	modified = true;
	saved = true;
	updateHeaders();
    
private voidsetAddressHeader(java.lang.String name, javax.mail.Address[] addresses)

	String s = InternetAddress.toString(addresses);
	if (s == null)
	    removeHeader(name);
	else
	    setHeader(name, s);
    
public voidsetContent(java.lang.Object o, java.lang.String type)
A convenience method for setting this Message's content.

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 setContent(foobar, "application/x-foobar"), 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
exception
IllegalWriteException if the underlying implementation does not support modification of existing values
exception
IllegalStateException if this message is obtained from a READ_ONLY folder.
exception
MessagingException

	if (o instanceof Multipart)
	    setContent((Multipart)o);
	else
	    setDataHandler(new DataHandler(o, type));
    
public voidsetContent(javax.mail.Multipart mp)
This method sets the Message's content to a Multipart object.

param
mp The multipart object that is the Message's content
exception
IllegalWriteException if the underlying implementation does not support modification of existing values
exception
IllegalStateException if this message is obtained from a READ_ONLY folder.
exception
MessagingException

	setDataHandler(new DataHandler(mp, mp.getContentType()));
	mp.setParent(this);
    
public voidsetContentID(java.lang.String cid)
Set the "Content-ID" header field of this Message. If the cid parameter is null, any existing "Content-ID" is removed.

exception
IllegalWriteException if the underlying implementation does not support modification
exception
IllegalStateException if this message is obtained from a READ_ONLY folder.
exception
MessagingException

	if (cid == null)
	    removeHeader("Content-ID");
	else
	    setHeader("Content-ID", cid);
    
public voidsetContentLanguage(java.lang.String[] languages)
Set the "Content-Language" header of this MimePart. The Content-Language header is defined by RFC 1766.

param
languages array of language tags
exception
IllegalWriteException if the underlying implementation does not support modification
exception
IllegalStateException if this message is obtained from a READ_ONLY folder.
exception
MessagingException

	MimeBodyPart.setContentLanguage(this, languages);
    
public voidsetContentMD5(java.lang.String md5)
Set the "Content-MD5" header field of this Message.

exception
IllegalWriteException if the underlying implementation does not support modification
exception
IllegalStateException if this message is obtained from a READ_ONLY folder.
exception
MessagingException

	setHeader("Content-MD5", md5);
    
public synchronized voidsetDataHandler(javax.activation.DataHandler dh)
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.
exception
IllegalWriteException if the underlying implementation does not support modification
exception
IllegalStateException if this message is obtained from a READ_ONLY folder.
exception
MessagingException

	this.dh = dh;
	cachedContent = null;
	MimeBodyPart.invalidateContentHeaders(this);
    
public voidsetDescription(java.lang.String description)
Set the "Content-Description" header field for this Message. If the description parameter is null, then any existing "Content-Description" fields are removed.

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.

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
exception
IllegalWriteException if the underlying implementation does not support modification
exception
IllegalStateException if this message is obtained from a READ_ONLY folder.
exception
MessagingException. An UnsupportedEncodingException may be included in the exception chain if the charset conversion fails.

	setDescription(description, null);
    
public voidsetDescription(java.lang.String description, java.lang.String charset)
Set the "Content-Description" header field for this Message. If the description parameter is null, then any existing "Content-Description" fields are removed.

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.

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
exception
IllegalWriteException if the underlying implementation does not support modification
exception
IllegalStateException if this message is obtained from a READ_ONLY folder.
exception
MessagingException. An UnsupportedEncodingException may be included in the exception chain if the charset conversion fails.

	MimeBodyPart.setDescription(this, description, charset);
    
public voidsetDisposition(java.lang.String disposition)
Set the "Content-Disposition" header field of this Message. If disposition is null, any existing "Content-Disposition" header field is removed.

exception
IllegalWriteException if the underlying implementation does not support modification
exception
IllegalStateException if this message is obtained from a READ_ONLY folder.
exception
MessagingException

	MimeBodyPart.setDisposition(this, disposition);
    
public voidsetFileName(java.lang.String filename)
Set the filename associated with this part, if possible.

Sets the "filename" parameter of the "Content-Disposition" header field of this message.

If the mail.mime.encodefilename 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.

exception
IllegalWriteException if the underlying implementation does not support modification
exception
IllegalStateException if this message is obtained from a READ_ONLY folder.
exception
MessagingException

	MimeBodyPart.setFileName(this, filename);	
    
public synchronized voidsetFlags(javax.mail.Flags flag, boolean set)
Set the flags for this message.

This implementation modifies the flags field.

exception
IllegalWriteException if the underlying implementation does not support modification
exception
IllegalStateException if this message is obtained from a READ_ONLY folder.
exception
MessagingException

	if (set)
	    flags.add(flag);
	else
	    flags.remove(flag);
    
public voidsetFrom(javax.mail.Address address)
Set the RFC 822 "From" header field. Any existing values are replaced with the given address. If address is null, this header is removed.

param
address the sender of this message
exception
IllegalWriteException if the underlying implementation does not support modification of existing values
exception
IllegalStateException if this message is obtained from a READ_ONLY folder.
exception
MessagingException

	if (address == null)
	    removeHeader("From");
	else
	    setHeader("From", address.toString());
    
public voidsetFrom()
Set the RFC 822 "From" header field using the value of the InternetAddress.getLocalAddress method.

exception
IllegalWriteException if the underlying implementation does not support modification of existing values
exception
IllegalStateException if this message is obtained from a READ_ONLY folder.
exception
MessagingException

	InternetAddress me = InternetAddress.getLocalAddress(session);
	if (me != null)
	    setFrom(me);
	else
	    throw new MessagingException("No From address");
    
public voidsetHeader(java.lang.String name, java.lang.String value)
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
see
javax.mail.internet.MimeUtility
exception
IllegalWriteException if the underlying implementation does not support modification
exception
IllegalStateException if this message is obtained from a READ_ONLY folder.
exception
MessagingException

	headers.setHeader(name, value);	
    
public voidsetRecipients(javax.mail.Message$RecipientType type, javax.mail.Address[] addresses)
Set the specified recipient type to the given addresses. If the address parameter is null, the corresponding recipient field is removed.

param
type Recipient type
param
addresses Addresses
exception
IllegalWriteException if the underlying implementation does not support modification of existing values
exception
IllegalStateException if this message is obtained from a READ_ONLY folder.
exception
MessagingException
see
#getRecipients

	if (type == RecipientType.NEWSGROUPS) {
	    if (addresses == null || addresses.length == 0)
		removeHeader("Newsgroups");
	    else
		setHeader("Newsgroups", NewsAddress.toString(addresses));
	} else
	    setAddressHeader(getHeaderName(type), addresses);
    
public voidsetRecipients(javax.mail.Message$RecipientType type, java.lang.String addresses)
Set the specified recipient type to the given addresses. If the address parameter is null, the corresponding recipient field is removed.

param
type Recipient type
param
addresses Addresses
exception
AddressException if the attempt to parse the addresses String fails
exception
IllegalWriteException if the underlying implementation does not support modification of existing values
exception
IllegalStateException if this message is obtained from a READ_ONLY folder.
exception
MessagingException
see
#getRecipients
since
JavaMail 1.2

        if (type == RecipientType.NEWSGROUPS) {
            if (addresses == null || addresses.length() == 0)
                removeHeader("Newsgroups");
            else
                setHeader("Newsgroups", addresses);
        } else
            setAddressHeader(getHeaderName(type), InternetAddress.parse(addresses));
    
public voidsetReplyTo(javax.mail.Address[] addresses)
Set the RFC 822 "Reply-To" header field. If the address parameter is null, this header is removed.

exception
IllegalWriteException if the underlying implementation does not support modification of existing values
exception
IllegalStateException if this message is obtained from a READ_ONLY folder.
exception
MessagingException

	setAddressHeader("Reply-To", addresses);
    
public voidsetSender(javax.mail.Address address)
Set the RFC 822 "Sender" header field. Any existing values are replaced with the given address. If address is null, this header is removed.

param
address the sender of this message
exception
IllegalWriteException if the underlying implementation does not support modification of existing values
exception
IllegalStateException if this message is obtained from a READ_ONLY folder.
exception
MessagingException
since
JavaMail 1.3

	if (address == null)
	    removeHeader("Sender");
	else
	    setHeader("Sender", address.toString());
    
public voidsetSentDate(java.util.Date d)
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 null, the existing "Date" field is removed.

exception
IllegalWriteException if the underlying implementation does not support modification
exception
IllegalStateException if this message is obtained from a READ_ONLY folder.
exception
MessagingException

	if (d == null)
	    removeHeader("Date");
	else {
	    synchronized (mailDateFormat) {
		setHeader("Date", mailDateFormat.format(d));
	    }
	}
    
public voidsetSubject(java.lang.String subject)
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.

The application must ensure that the subject does not contain any line breaks.

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
exception
IllegalWriteException if the underlying implementation does not support modification of existing values
exception
IllegalStateException if this message is obtained from a READ_ONLY folder.
exception
MessagingException. An UnsupportedEncodingException may be included in the exception chain if the charset conversion fails.

	setSubject(subject, null);
    
public voidsetSubject(java.lang.String subject, java.lang.String charset)
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.

The application must ensure that the subject does not contain any line breaks.

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
exception
IllegalWriteException if the underlying implementation does not support modification of existing values
exception
IllegalStateException if this message is obtained from a READ_ONLY folder.
exception
MessagingException. An UnsupportedEncodingException may be included in the exception chain if the charset conversion fails.

	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);
	    }
	}
    
public voidsetText(java.lang.String text)
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.

Note that there may be a performance penalty if text is large, since this method may have to scan all the characters to determine what charset to use.

If the charset is already known, use the setText method that takes the charset parameter.

param
text the text content to set
exception
MessagingException if an error occurs
see
#setText(String text, String charset)

	setText(text, null);
    
public voidsetText(java.lang.String text, java.lang.String charset)
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
exception
MessagingException if an error occurs

	MimeBodyPart.setText(this, text, charset, "plain");
    
public voidsetText(java.lang.String text, java.lang.String charset, java.lang.String subtype)
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")
exception
MessagingException if an error occurs
since
JavaMail 1.4

	MimeBodyPart.setText(this, text, charset, subtype);
    
protected voidupdateHeaders()
Called by the saveChanges method to actually update the MIME headers. The implementation here sets the Content-Transfer-Encoding header (if needed and not already set), the MIME-Version header and the Message-ID header. Also, if the content of this message is a MimeMultipart, it's updateHeaders method is called.

exception
IllegalWriteException if the underlying implementation does not support modification
exception
IllegalStateException if this message is obtained from a READ_ONLY folder.
exception
MessagingException

	MimeBodyPart.updateHeaders(this);	
	setHeader("MIME-Version", "1.0");
        updateMessageID();

	/*
	 * If we've cached a Multipart or Message object then
	 * we're now committed to using this instance of the
	 * object and we discard any stream data used to create
	 * this object.
	 */
	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;
	}
    
protected voidupdateMessageID()
Update the Message-ID header. This method is called by the updateHeaders and allows a subclass to override only the algorithm for choosing a Message-ID.

since
JavaMail 1.4

	setHeader("Message-ID", 
		  "<" + UniqueValue.getUniqueMessageIDValue(session) + ">");
          
    
public voidwriteTo(java.io.OutputStream os)
Output the message as an RFC 822 format stream.

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.

This implementation calls the writeTo(OutputStream, String[]) method with a null ignore list.

exception
IOException if an error occurs writing to the stream or if an error is generated by the javax.activation layer.
exception
MessagingException
see
javax.activation.DataHandler#writeTo

	writeTo(os, null);
    
public voidwriteTo(java.io.OutputStream os, java.lang.String[] ignoreList)
Output the message as an RFC 822 format stream, without specified headers. If the saved flag is not set, the saveChanges method is called. If the modified flag is not set and the content array is not null, the content array is written directly, after writing the appropriate message headers.

exception
javax.mail.MessagingException
exception
IOException if an error occurs writing to the stream or if an error is generated by the javax.activation layer.
see
javax.activation.DataHandler#writeTo

	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 hdrLines = getNonMatchingHeaderLines(ignoreList);
	LineOutputStream los = new LineOutputStream(os);
	while (hdrLines.hasMoreElements())
	    los.writeln((String)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 = getContentStream();
	    // now copy the data to the output stream
	    byte[] buf = new byte[8192];
	    int len;
	    while ((len = is.read(buf)) > 0)
		os.write(buf, 0, len);
	    is.close();
	    buf = null;
	} else {
	    os.write(content);
	}
	os.flush();