jakarta.mail

Interface Part

All Known Subinterfaces:

MimePart

All Known Implementing Classes:

BodyPart, Message, MimeBodyPart, MimeMessage, PreencodedMimeBodyPart

public interface Part

The Part interface is the common base interface for Messages and BodyParts.

Part consists of a set of attributes and a "Content".

Attributes:

The Jakarta Mail API defines a set of standard Part attributes that are considered to be common to most existing Mail systems. These attributes have their own settor and gettor methods. Mail systems may support other Part attributes as well, these are represented as name-value pairs where both the name and value are Strings.

Content:

The data type of the "content" is returned by the getContentType() method. The MIME typing system is used to name data types.

The "content" of a Part is available in various formats:

• As a DataHandler - using the getDataHandler() method. The "content" of a Part is also available through a jakarta.activation.DataHandler object. The DataHandler object allows clients to discover the operations available on the content, and to instantiate the appropriate component to perform those operations.
• As an input stream - using the getInputStream() method. Any mail-specific encodings are decoded before this stream is returned.
• As a Java object - using the getContent() method. This method returns the "content" as a Java object. The returned object is of course dependent on the content itself. In particular, a "multipart" Part's content is always a Multipart or subclass thereof. That is, getContent() on a "multipart" type Part will always return a Multipart (or subclass) object.

Part provides the writeTo() method that streams out its bytestream in mail-safe form suitable for transmission. This bytestream is typically an aggregation of the Part attributes and its content's bytestream.

Message and BodyPart implement the Part interface. Note that in MIME parlance, Part models an Entity (RFC 2045, Section 2.4).

Author:

John Mani

Field Summary

Fields

Modifier and Type	Field and Description
static String	ATTACHMENT This part should be presented as an attachment.
static String	INLINE This part should be presented inline.

Method Summary

Modifier and Type	Method and Description
void	addHeader(String header_name, String header_value) Add this value to the existing values for this header_name.
Enumeration<Header>	getAllHeaders() Return all the headers from this part as an Enumeration of Header objects.
Object	getContent() Return the content as a Java object.
String	getContentType() Returns the Content-Type of the content of this part.
DataHandler	getDataHandler() Return a DataHandler for the content within this part.
String	getDescription() Return a description String for this part.
String	getDisposition() Return the disposition of this part.
String	getFileName() Get the filename associated with this part, if possible.
String[]	getHeader(String header_name) Get all the headers for this header name.
InputStream	getInputStream() Return an input stream for this part's "content".
int	getLineCount() Return the number of lines in the content of this part.
Enumeration<Header>	getMatchingHeaders(String[] header_names) Return matching headers from this part as an Enumeration of Header objects.
Enumeration<Header>	getNonMatchingHeaders(String[] header_names) Return non-matching headers from this envelope as an Enumeration of Header objects.
int	getSize() Return the size of the content of this part in bytes.
boolean	isMimeType(String mimeType) Is this Part of the specified MIME type? This method compares only the primaryType and subType.
void	removeHeader(String header_name) Remove all headers with this name.
void	setContent(Multipart mp) This method sets the given Multipart object as this message's content.
void	setContent(Object obj, String type) A convenience method for setting this part's content.
void	setDataHandler(DataHandler dh) This method provides the mechanism to set this part's content.
void	setDescription(String description) Set a description String for this part.
void	setDisposition(String disposition) Set the disposition of this part.
void	setFileName(String filename) Set the filename associated with this part, if possible.
void	setHeader(String header_name, String header_value) Set the value for this header_name.
void	setText(String text) A convenience method that sets the given String as this part's content with a MIME type of "text/plain".
void	writeTo(OutputStream os) Output a bytestream for this Part.

Field Detail

ATTACHMENT

static final String ATTACHMENT

This part should be presented as an attachment.

See Also:

getDisposition(), setDisposition(java.lang.String), Constant Field Values

INLINE

static final String INLINE

This part should be presented inline.

See Also:

getDisposition(), setDisposition(java.lang.String), Constant Field Values

Method Detail

getSize

int getSize()
     throws MessagingException

Return the size of the content of this part in bytes. Return -1 if the size cannot be determined.

Note that the size may not be an exact measure of the content size and may or may not account for any transfer encoding of the content. The size is appropriate for display in a user interface to give the user a rough idea of the size of this part.

Returns:

size of content in bytes

Throws:

MessagingException - for failures

getLineCount

int getLineCount()
          throws MessagingException

Return the number of lines in the content of this part. Return -1 if the 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.

Returns:

number of lines in the content.

Throws:

MessagingException - for failures

getContentType

String getContentType()
               throws MessagingException

Returns the Content-Type of the content of this part. Returns null if the Content-Type could not be determined.

The MIME typing system is used to name Content-types.

Returns:

The ContentType of this part

Throws:

MessagingException - for failures

See Also:

DataHandler

isMimeType

boolean isMimeType(String mimeType)
            throws MessagingException

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.

Parameters:

mimeType - the MIME type to test

Returns:

true if this part is of the specified type

Throws:

MessagingException - for failures

getDisposition

String getDisposition()
               throws MessagingException

Return the disposition of this part. The disposition describes how the part should be presented to the user. (See RFC 2183.) The return value should be considered without regard to case. For example:

 String disp = part.getDisposition();
 if (disp == null || disp.equalsIgnoreCase(Part.ATTACHMENT))
        // treat as attachment if not first part
 

Returns:

disposition of this part, or null if unknown

Throws:

MessagingException - for failures

See Also:

ATTACHMENT, INLINE, getFileName()

setDisposition

void setDisposition(String disposition)
             throws MessagingException

Set the disposition of this part.

Parameters:

disposition - disposition of this part

Throws:

IllegalWriteException - if the underlying implementation does not support modification of this header

IllegalStateException - if this Part is obtained from a READ_ONLY folder

MessagingException - for other failures

See Also:

ATTACHMENT, INLINE, setFileName(java.lang.String)

getDescription

String getDescription()
               throws MessagingException

Return a description String for this part. This typically associates some descriptive information with this part. Returns null if none is available.

Returns:

description of this part

Throws:

MessagingException - for failures

setDescription

void setDescription(String description)
             throws MessagingException

Set a description String for this part. This typically associates some descriptive information with this part.

Parameters:

description - description of this part

Throws:

IllegalWriteException - if the underlying implementation does not support modification of this header

IllegalStateException - if this Part is obtained from a READ_ONLY folder

MessagingException - for other failures

getFileName

String getFileName()
            throws MessagingException

Get the filename associated with this part, if possible. Useful if this part represents an "attachment" that was loaded from a file. The filename will usually be a simple name, not including directory components.

Returns:

Filename to associate with this part

Throws:

MessagingException - for failures

setFileName

void setFileName(String filename)
          throws MessagingException

Set the filename associated with this part, if possible. Useful if this part represents an "attachment" that was loaded from a file. The filename will usually be a simple name, not including directory components.

Parameters:

filename - Filename to associate with this part

Throws:

IllegalWriteException - if the underlying implementation does not support modification of this header

IllegalStateException - if this Part is obtained from a READ_ONLY folder

MessagingException - for other failures

getInputStream

InputStream getInputStream()
                    throws IOException,
                           MessagingException

Return an input stream for this part's "content". Any mail-specific transfer encodings will be decoded before the input stream is provided.

This is typically a convenience method that just invokes the DataHandler's getInputStream() method.

Returns:

an InputStream

Throws:

IOException - this is typically thrown by the DataHandler. Refer to the documentation for jakarta.activation.DataHandler for more details.

MessagingException - for other failures

See Also:

getDataHandler(), DataHandler.getInputStream()

getDataHandler

DataHandler getDataHandler()
                    throws MessagingException

Return a DataHandler for the content within this part. The DataHandler allows clients to operate on as well as retrieve the content.

Returns:

DataHandler for the content

Throws:

MessagingException - for failures

getContent

Object getContent()
           throws IOException,
                  MessagingException

Return the content as a Java object. The type of the returned object is of course dependent on the content itself. For example, the object returned for "text/plain" content is usually a String object. The object returned for a "multipart" content is always a Multipart subclass. For content-types that are unknown to the DataHandler system, an input stream is returned as the content

This is a convenience method that just invokes the DataHandler's getContent() method

Returns:

Object

Throws:

IOException - this is typically thrown by the DataHandler. Refer to the documentation for jakarta.activation.DataHandler for more details.

MessagingException - for other failures

See Also:

DataHandler.getContent()

setDataHandler

void setDataHandler(DataHandler dh)
             throws MessagingException

This method provides the mechanism to set this part's content. The DataHandler wraps around the actual content.

Parameters:

dh - The DataHandler for the content.

Throws:

IllegalWriteException - if the underlying implementation does not support modification of existing values

IllegalStateException - if this Part is obtained from a READ_ONLY folder

MessagingException - for other failures

setContent

void setContent(Object obj,
                String type)
         throws MessagingException

A convenience method for setting this part's content. The part internally wraps the content in a DataHandler.

Note that a DataContentHandler class for the specified type should be available to the Jakarta Mail 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.

Parameters:

obj - A java object.

type - MIME type of this object.

Throws:

IllegalWriteException - if the underlying implementation does not support modification of existing values

IllegalStateException - if this Part is obtained from a READ_ONLY folder

MessagingException - for other failures

setText

void setText(String text)
      throws MessagingException

A convenience method that sets the given String as this part's content with a MIME type of "text/plain".

Parameters:

text - The text that is the Message's content.

Throws:

IllegalWriteException - if the underlying implementation does not support modification of existing values

IllegalStateException - if this Part is obtained from a READ_ONLY folder

MessagingException - for other failures

setContent

void setContent(Multipart mp)
         throws MessagingException

This method sets the given Multipart object as this message's content.

Parameters:

mp - The multipart object that is the Message's content

Throws:

IllegalWriteException - if the underlying implementation does not support modification of existing values

IllegalStateException - if this Part is obtained from a READ_ONLY folder

MessagingException - for other failures

writeTo

void writeTo(OutputStream os)
      throws IOException,
             MessagingException

Output a bytestream for this Part. This bytestream is typically an aggregration of the Part attributes and an appropriately encoded bytestream from its 'content'.

Classes that implement the Part interface decide on the appropriate encoding algorithm to be used.

The bytestream is typically used for sending.

Parameters:

os - the stream to write to

Throws:

IOException - if an error occurs writing to the stream or if an error is generated by the jakarta.activation layer.

MessagingException - if an error occurs fetching the data to be written

See Also:

DataHandler.writeTo(java.io.OutputStream)

getHeader

String[] getHeader(String header_name)
            throws MessagingException

Get all the headers for this header name. Returns null if no headers for this header name are available.

Parameters:

header_name - the name of this header

Returns:

the value fields for all headers with this name

Throws:

MessagingException - for failures

setHeader

void setHeader(String header_name,
               String header_value)
        throws MessagingException

Set the value for this header_name. Replaces all existing header values with this new value.

Parameters:

header_name - the name of this header

header_value - the value for this header

Throws:

IllegalWriteException - if the underlying implementation does not support modification of existing values

IllegalStateException - if this Part is obtained from a READ_ONLY folder

MessagingException - for other failures

addHeader

void addHeader(String header_name,
               String header_value)
        throws MessagingException

Add this value to the existing values for this header_name.

Parameters:

header_name - the name of this header

header_value - the value for this header

Throws:

IllegalWriteException - if the underlying implementation does not support modification of existing values

IllegalStateException - if this Part is obtained from a READ_ONLY folder

MessagingException - for other failures

removeHeader

void removeHeader(String header_name)
           throws MessagingException

Remove all headers with this name.

Parameters:

header_name - the name of this header

Throws:

IllegalWriteException - if the underlying implementation does not support modification of existing values

IllegalStateException - if this Part is obtained from a READ_ONLY folder

MessagingException - for other failures

getAllHeaders

Enumeration<Header> getAllHeaders()
                           throws MessagingException

Return all the headers from this part as an Enumeration of Header objects.

Returns:

enumeration of Header objects

Throws:

MessagingException - for failures

getMatchingHeaders

Enumeration<Header> getMatchingHeaders(String[] header_names)
                                throws MessagingException

Return matching headers from this part as an Enumeration of Header objects.

Parameters:

header_names - the headers to match

Returns:

enumeration of Header objects

Throws:

MessagingException - for failures

getNonMatchingHeaders

Enumeration<Header> getNonMatchingHeaders(String[] header_names)
                                   throws MessagingException

Return non-matching headers from this envelope as an Enumeration of Header objects.

Parameters:

header_names - the headers to not match

Returns:

enumeration of Header objects

Throws:

MessagingException - for failures