Package 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).

  • Field Details

  • Method Details

    • 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:

    • 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:

    • 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:

    • 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 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:

    • 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:

    • 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