Java Reference
In-Depth Information
• Methods for getting and setting the headers of the part
• Methods for getting and setting the contents of the part
The attributes of the part are details that aren't explicitly specified in the message's
header, such as the size of the message or the date it was received. The headers, by
contrast, are name-value pairs included at the front of the part. Finally, the content of
the part is the actual data that the message is trying to transmit.
Attributes
The JavaMail API defines five attributes for parts:
Size
The approximate number of bytes in the part
Line count
The number of lines in the part
Disposition
Whether the part is an attachment or should be displayed in-line
Description
A brief text summary of the part
Filename
The name of the file that the attachment came from
Not all parts have all attributes. For instance, a part that does not represent an attached
file is unlikely to have a filename attribute. Each attribute is mapped to a getter method:
public
int
getSize
()
throws
MessagingException
public
int
getLineCount
()
throws
MessagingException
public
String
getDisposition
()
throws
MessagingException
public
String
getDescription
()
throws
MessagingException
public
String
getFileName
()
throws
MessagingException
,
ParseException
Generally, each getter method returns null or -1 if a part doesn't possess the requested
attribute. It throws a
MessagingException
if there's some problem retrieving the mes‐
sage; for instance, if the connection goes down while the message is being retrieved.
The
getSize()
method returns the approximate number of bytes in the part. Depending
on the server and protocol, this may or may not account for changes in the size caused
by operations such as Base64 encoding the data.
The
getLineCount()
method returns the approximate number of lines in the content
of the part or -1 if the number of lines isn't known. Again, the number returned may or
may not account for changes in the size of the part caused by the part's encoding.
