public class

MimeMultipart

extends Multipart
java.lang.Object
   ↳ com.google.code.javax.mail.Multipart
     ↳ com.google.code.javax.mail.internet.MimeMultipart

Class Overview

The MimeMultipart class is an implementation of the abstract Multipart class that uses MIME conventions for the multipart data.

A MimeMultipart is obtained from a MimePart whose primary type is "multipart" (by invoking the part's getContent() method) or it can be created by a client as part of creating a new MimeMessage.

The default multipart subtype is "mixed". The other multipart subtypes, such as "alternative", "related", and so on, can be implemented as subclasses of MimeMultipart with additional methods to implement the additional semantics of that type of multipart content. The intent is that service providers, mail JavaBean writers and mail clients will write many such subclasses and their Command Beans, and will install them into the JavaBeans Activation Framework, so that any JavaMail implementation and its clients can transparently find and use these classes. Thus, a MIME multipart handler is treated just like any other type handler, thereby decoupling the process of providing multipart handlers from the JavaMail API. Lacking these additional MimeMultipart subclasses, all subtypes of MIME multipart data appear as MimeMultipart objects.

An application can directly construct a MIME multipart object of any subtype by using the MimeMultipart(String subtype) constructor. For example, to create a "multipart/alternative" object, use new MimeMultipart("alternative").

The mail.mime.multipart.ignoremissingendboundary property may be set to false to cause a MessagingException to be thrown if the multipart data does not end with the required end boundary line. If this property is set to true or not set, missing end boundaries are not considered an error and the final body part ends at the end of the data.

The mail.mime.multipart.ignoremissingboundaryparameter System property may be set to false to cause a MessagingException to be thrown if the Content-Type of the MimeMultipart does not include a boundary parameter. If this property is set to true or not set, the multipart parsing code will look for a line that looks like a bounary line and use that as the boundary separating the parts.

The current implementation also supports the following properties:

The mail.mime.multipart.ignoreexistingboundaryparameter System property may be set to true to cause any boundary to be ignored and instead search for a boundary line in the message as with mail.mime.multipart.ignoremissingboundaryparameter.

Normally, when writing out a MimeMultipart that contains no body parts, or when trying to parse a multipart message with no body parts, a MessagingException is thrown. The MIME spec does not allow multipart content with no body parts. The mail.mime.multipart.allowempty System property may be set to true to override this behavior. When writing out such a MimeMultipart, a single empty part will be included. When reading such a multipart, a MimeMultipart will be created with no body parts.

Summary

Fields
private boolean allowEmpty
private boolean bmparse
private boolean complete Have we seen the final bounary line?
protected DataSource ds The DataSource supplying our InputStream.
private boolean ignoreExistingBoundaryParameter
private boolean ignoreMissingBoundaryParameter
private boolean ignoreMissingEndBoundary Flags to control parsing, initialized from System properties in the parse() method.
protected boolean parsed Have we parsed the data from our InputStream yet? Defaults to true; set to false when our constructor is given a DataSource with an InputStream that we need to parse.
private String preamble The MIME multipart preamble text, the text that occurs before the first boundary line.
[Expand]
Inherited Fields
From class com.google.code.javax.mail.Multipart
Public Constructors
MimeMultipart()
Default constructor.
MimeMultipart(String subtype)
Construct a MimeMultipart object of the given subtype.
MimeMultipart(DataSource ds)
Constructs a MimeMultipart object and its bodyparts from the given DataSource.
Public Methods
synchronized void addBodyPart(BodyPart part)
Adds a Part to the multipart.
synchronized void addBodyPart(BodyPart part, int index)
Adds a BodyPart at position index.
synchronized BodyPart getBodyPart(int index)
Get the specified BodyPart.
synchronized BodyPart getBodyPart(String CID)
Get the MimeBodyPart referred to by the given ContentID (CID).
synchronized int getCount()
Return the number of enclosed BodyPart objects.
synchronized String getPreamble()
Get the preamble text, if any, that appears before the first body part of this multipart.
synchronized boolean isComplete()
Return true if the final boundary line for this multipart was seen.
boolean removeBodyPart(BodyPart part)
Remove the specified part from the multipart message.
void removeBodyPart(int index)
Remove the part at specified location (starting from 0).
synchronized void setPreamble(String preamble)
Set the preamble text to be included before the first body part.
synchronized void setSubType(String subtype)
Set the subtype.
synchronized void writeTo(OutputStream os)
Iterates through all the parts and outputs each MIME part separated by a boundary.
Protected Methods
InternetHeaders createInternetHeaders(InputStream is)
Create and return an InternetHeaders object that loads the headers from the given InputStream.
MimeBodyPart createMimeBodyPart(InputStream is)
Create and return a MimeBodyPart object to represent a body part parsed from the InputStream.
MimeBodyPart createMimeBodyPart(InternetHeaders headers, byte[] content)
Create and return a MimeBodyPart object to represent a body part parsed from the InputStream.
synchronized void parse()
Parse the InputStream from our DataSource, constructing the appropriate MimeBodyParts.
synchronized void updateHeaders()
Update headers.
[Expand]
Inherited Methods
From class com.google.code.javax.mail.Multipart
From class java.lang.Object

Fields

private boolean allowEmpty

private boolean bmparse

private boolean complete

Have we seen the final bounary line?

protected DataSource ds

The DataSource supplying our InputStream.

private boolean ignoreExistingBoundaryParameter

private boolean ignoreMissingBoundaryParameter

private boolean ignoreMissingEndBoundary

Flags to control parsing, initialized from System properties in the parse() method.

protected boolean parsed

Have we parsed the data from our InputStream yet? Defaults to true; set to false when our constructor is given a DataSource with an InputStream that we need to parse.

private String preamble

The MIME multipart preamble text, the text that occurs before the first boundary line.

Public Constructors

public MimeMultipart ()

Default constructor. An empty MimeMultipart object is created. Its content type is set to "multipart/mixed". A unique boundary string is generated and this string is setup as the "boundary" parameter for the contentType field.

MimeBodyParts may be added later.

public MimeMultipart (String subtype)

Construct a MimeMultipart object of the given subtype. A unique boundary string is generated and this string is setup as the "boundary" parameter for the contentType field.

MimeBodyParts may be added later.

Parameters
subtype

public MimeMultipart (DataSource ds)

Constructs a MimeMultipart object and its bodyparts from the given DataSource.

This constructor handles as a special case the situation where the given DataSource is a MultipartDataSource object. In this case, this method just invokes the superclass (i.e., Multipart) constructor that takes a MultipartDataSource object.

Otherwise, the DataSource is assumed to provide a MIME multipart byte stream. The parsed flag is set to false. When the data for the body parts are needed, the parser extracts the "boundary" parameter from the content type of this DataSource, skips the 'preamble' and reads bytes till the terminating boundary and creates MimeBodyParts for each part of the stream.

Parameters
ds DataSource, can be a MultipartDataSource

Public Methods

public synchronized void addBodyPart (BodyPart part)

Adds a Part to the multipart. The BodyPart is appended to the list of existing Parts.

Parameters
part The Part to be appended
Throws
IllegalWriteException if the underlying implementation does not support modification of existing values
MessagingException

public synchronized void addBodyPart (BodyPart part, int index)

Adds a BodyPart at position index. If index is not the last one in the list, the subsequent parts are shifted up. If index is larger than the number of parts present, the BodyPart is appended to the end.

Parameters
part The BodyPart to be inserted
index Location where to insert the part
Throws
IllegalWriteException if the underlying implementation does not support modification of existing values
MessagingException

public synchronized BodyPart getBodyPart (int index)

Get the specified BodyPart. BodyParts are numbered starting at 0.

Parameters
index The index of the desired BodyPart
Returns
  • the Part
Throws
MessagingException if no such BodyPart exists

public synchronized BodyPart getBodyPart (String CID)

Get the MimeBodyPart referred to by the given ContentID (CID). Returns null if the part is not found.

Parameters
CID The ContentID of the desired part
Returns
  • the Part

public synchronized int getCount ()

Return the number of enclosed BodyPart objects.

Returns
  • number of parts

public synchronized String getPreamble ()

Get the preamble text, if any, that appears before the first body part of this multipart. Some protocols, such as IMAP, will not allow access to the preamble text.

Returns
  • the preamble text, or null if no preamble

public synchronized boolean isComplete ()

Return true if the final boundary line for this multipart was seen. When parsing multipart content, this class will (by default) terminate parsing with no error if the end of input is reached before seeing the final multipart boundary line. In such a case, this method will return false. (If the System property "mail.mime.multipart.ignoremissingendboundary" is set to false, parsing such a message will instead throw a MessagingException.)

Returns
  • true if the final boundary line was seen

public boolean removeBodyPart (BodyPart part)

Remove the specified part from the multipart message. Shifts all the parts after the removed part down one.

Parameters
part The part to remove
Returns
  • true if part removed, false otherwise
Throws
MessagingException if no such Part exists
IllegalWriteException if the underlying implementation does not support modification of existing values

public void removeBodyPart (int index)

Remove the part at specified location (starting from 0). Shifts all the parts after the removed part down one.

Parameters
index Index of the part to remove
Throws
IndexOutOfBoundsException if the given index is out of range.
IllegalWriteException if the underlying implementation does not support modification of existing values
MessagingException

public synchronized void setPreamble (String preamble)

Set the preamble text to be included before the first body part. Applications should generally not include any preamble text. In some cases it may be helpful to include preamble text with instructions for users of pre-MIME software. The preamble text should be complete lines, including newlines.

Parameters
preamble The preamble text

public synchronized void setSubType (String subtype)

Set the subtype. This method should be invoked only on a new MimeMultipart object created by the client. The default subtype of such a multipart object is "mixed".

Parameters
subtype Subtype

public synchronized void writeTo (OutputStream os)

Iterates through all the parts and outputs each MIME part separated by a boundary.

Parameters
os
Throws
IOException
MessagingException

Protected Methods

protected InternetHeaders createInternetHeaders (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.

Parameters
is The InputStream to read the headers from

protected MimeBodyPart createMimeBodyPart (InputStream is)

Create and return a MimeBodyPart object to represent a body part parsed from the InputStream. Subclasses can override this method to return a subclass of MimeBodyPart, if necessary. This implementation simply constructs and returns a MimeBodyPart object.

Parameters
is InputStream containing the body part

protected MimeBodyPart createMimeBodyPart (InternetHeaders headers, byte[] content)

Create and return a MimeBodyPart object to represent a body part parsed from the InputStream. Subclasses can override this method to return a subclass of MimeBodyPart, if necessary. This implementation simply constructs and returns a MimeBodyPart object.

Parameters
headers The headers for the body part
content The content of the body part

protected synchronized void parse ()

Parse the InputStream from our DataSource, constructing the appropriate MimeBodyParts. The parsed flag is set to true, and if true on entry nothing is done. This method is called by all other methods that need data for the body parts, to make sure the data has been parsed.

protected synchronized void updateHeaders ()

Update headers. The default implementation here just calls the updateHeaders method on each of its children BodyParts.

Note that the boundary parameter is already set up when a new and empty MimeMultipart object is created.

This method is called when the saveChanges method is invoked on the Message object containing this Multipart. This is typically done as part of the Message send process, however note that a client is free to call it any number of times. So if the header updating process is expensive for a specific MimeMultipart subclass, then it might itself want to track whether its internal state actually did change, and do the header updating only if necessary.