Name: sg39081 Date: 08/31/99


Create a multipart mail message comprising a text
part and a pdf stream part. If the InputStream
is created in one object and passed into the
DataSource, it throws an exception trying to
read the InputStream.

If the InputStream is created in the DataSource,
the InputStream can be read fine.

This is probably really more of a documentation issue.

I have wrapped the basic javamail classes with my own EmailMessage class to
hide all of the implementation details from our programmers. I've given
them the following method for adding attachments of any type to the message.

addAttachment(String contentType, InputStream in)

Because I don't know what type of InputStream that can be passed in, I can't
use any of the provided DataSource implementation classes (e.g.
java.activation.FileDataSource). So I have implemented my own class and
passed the contentType and InputStream object in the constructor:

The folowing is an example to demonstrate the problem.

public class MyDataSource implements java.activation.DataSource {
private String contentType ;
private InputStream in ;

// constructor
public MyDataSource(String contentType, InputStream in) {
this.contentType = contentType ;
this.in = in ;
}

...
// part of the DataHandler interface
public InputStream getInputStream( ) {
return in ;
}
}

I would have liked just to return the InputStream in the
getInputStreamMethod() like in the above, but in the course of executing the
sendMessage( ) method, it calls getInputStream( ) twice. The stream is
already consumed when the second getInputStream() is executed. So I'm
forced to write the stream to a temporary file (because it may not fit in a
memory resident ByteArrayInputStream), and return a new InputStream object
each time.

My question is, why does it call the getInputStream( ) method twice? Is it
to get the length first?

It took me quite a while to find the problem. Maybe some documentation
could be added to the javadoc somewhere.




Here's the code:

try {
   Properties props = new Properties() ;
   props.put("mail.smtp.host", myHost) ;
   javax.mail.Session mailSession = javax.mail.Session.getDefaultInstance(props, null) ;

   mailSession.setDebug(true) ;
   MimeMessage msg = new MimeMessage(mailSession) ;
   InternetAddress from = new InternetAddress("###@###.###") ;
   InternetAddress to = new InternetAddress("###@###.###") ;

   msg.setFrom(from) ;
   InternetAddress[] addr = {to} ;
   msg.setRecipients(Message.RecipientType.TO, addr) ;
   msg.setSubject("Test Message") ;
   msg.setSentDate(new Date()) ;
   msg.setHeader("X-Mailer", "msgsend") ;

   //createMessage(msg) ;
   MimeBodyPart mbp1 = new MimeBodyPart() ;
   mbp1.setText("Text part") ;
   MimeBodyPart mbp2 = new MimeBodyPart() ;

   InputStream pdf = new FileInputStream("myfile.pdf") ;
   DataSource mailds = new PdfDataSource(pdf) ;

   mbp2.setDataHandler(new DataHandler(mailds)) ;
   Multipart mp = new MimeMultipart() ;
   mp.addBodyPart(mbp1) ;
   mp.addBodyPart(mbp2) ;
   msg.setContent(mp) ;
   Transport.send(msg) ;

}

// Here's the PdfDataSource class
class PdfDataSource implements DataSource {
private InputStream pdf = null ;

   // Constructor - passes in the InputStream
   PdfDataSource(InputStream pdf) {
      this.pdf = pdf ;
   }

   // Implement the DataSource interface
   public InputStream getInputStream() throws IOException {
       //If you create the pdf stream here with
       // the code below, the message is sent
       // correctly, with the pdf attachment
       //return new FileInputStream("myfile.pdf") ;

      // Using the passed in InputStream here
      // yields an empty PDF file
      return pdf ;
   }

   public OutputStream getOutputStream() throws IOException {
      throw new IOException("Can't do this") ;
   }

   public String getContentType() {
      return "application/pdf" ;
   }

   public String getName() {
      return "PDFDataSource" ;
   }
}


Here's the stacktrace from the exception:
java.io.IOException: read error
        at java.io.FileInputStream.read(FileInputStream.java:148)
        at javax.activation.DataHandler.writeTo(Compiled Code)
        at javax.mail.internet.MimeBodyPart.writeTo(Compiled Code)
        at javax.mail.internet.MimeBodyPart.writeTo(Compiled Code)
        at javax.mail.internet.MimeMultipart.writeTo(Compiled Code)
        at com.sun.mail.handlers.multipart_mixed.writeTo(multipart_mixed.java:78
)
        at javax.activation.ObjectDataContentHandler.writeTo(Compiled Code)
        at javax.activation.DataHandler.writeTo(Compiled Code)
        at javax.mail.internet.MimeBodyPart.writeTo(Compiled Code)
        at javax.mail.internet.MimeMessage.writeTo(Compiled Code)
        at com.sun.mail.smtp.SMTPTransport.sendMessage(Compiled Code)
        at javax.mail.Transport.send0(Compiled Code)
        at javax.mail.Transport.send(Transport.java:73)
        at MailTest.main(MailTest.java:45)
javax.mail.SendFailedException: Sending failed;
  nested exception is:
        javax.mail.MessagingException: IOException while sending message;
  nested exception is:
        java.io.IOException: read error
        at java.lang.Throwable.<init>(Compiled Code)
        at javax.mail.Transport.send0(Compiled Code)
        at javax.mail.Transport.send(Transport.java:73)
        at MailTest.main(MailTest.java:45)
(Review ID: 43632)
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