JMS BytesMessage for sending multiple documents - jms

Question

I have a requirement for a batch job that should send out emails.However I have to break it out in such a fashion that I need to handover the email details to another system via messaging which will then read the messages placed and send out emails leisurely.
My emails have attachments.How do I achieve this? There could be multiple attachments for a given email.
I read about bytes message but how do I use it for multiple attachments for a given email message?
Any thoughts about this?

Answer 1

You could send one JMS message containing email details (from, to list, subject, text), and after that send attachments as JMS bytes message, each attachment message with the same custom identifier.
Sender side
// create JMS Bytes message with mail content
// MailData class should implement java.io.Serializable)
MailData mailData = new MailData();
// emailID could be GUID or anything else that would uniquely identify mail
mailData.setEmailID(emailID);
mailData.setFrom(from);
mailData.setToList(toList);
mailData.setSubject(subject);
mailData.setText(text);
BytesMessage msg = session.createBytesMessage();
ByteArrayOutputStream bos = new ByteArrayOutputStream();
ObjectOutputStream out = new ObjectOutputStream(bos);
out.writeObject(mailData);
out.close();
bos.close();
msg.writeBytes(bos.toByteArray());
producer.send(msg);
// for the sake of simplicity, object attachment contains attachment name, MIME type
// and value as byte array
for(Attachment att : attachmentList) {
BytesMessage msgAtt = session.createBytesMessage();
// emailID
msgAtt.setStringProperty("emailId", emailID);
msgAtt.setStringProperty("fileName", att.getAttachmentName());
msgAtt.setStringProperty("mimeType", att.getMimeType());
// set bytes message payload to attachment content
msgAtt.writeBytes(att.getValue());
producer.send(msgAtt);
}
Receiver side
BytesMessage bytesMessage = (BytesMessage) message;
byte[] bytes = new byte[(int) bytesMessage.getBodyLength()];
bytesMessage.readBytes(bytes);
ByteArrayInputStream bis = new ByteArrayInputStream(bytesMessage);
ObjectInputStream in = new ObjectInputStream(bis);
MailData mailData = (MailData) in.readObject();
in.close();
bis.close();
// get data from queue with the same emailID
MessageConsumer consumer = session.createConsumer(queue, "emailID='"
+ mailData.getEmailID() + "'");
connection.start();
Message attMsg = null;
while((attMsg = consumer.receiveNoWait()) != null) {
String fileName = attMsg.getStringProperty("fileName");
String mimeType = att.getStringProperty("mimeType");
BytesMessage bytesMessage = (BytesMessage) attMsg;
byte[] attachmentValue = new byte[(int) bytesMessage.getBodyLength()];
bytesMessage.readBytes(attachmentValue);
}