I have a question about Java Mail and how it works with streams. In Java Mail 1.4.1 there is a MimeMessage constructor that accepts a stream. My understanding is that I could pass a stream to this constructor and it would parse it for me into a MimeMessage. I wrote 2 tests to prove this. The first test sends in a stream that contains only a partial multi-part MIME message. The second test sends in a stream that contains 2 complete multi-part MIME messages. Neither work the way I expected. The first does not throw an exception and the second reads the entire stream into a single message somehow. Is this a bug in Java Mail or am I using the wrong kind of streams? Or am I missing something bigger?
It is a little long but here is the test code:
import java.io.BufferedInputStream;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Properties;
import javax.activation.DataHandler;
import javax.activation.DataSource;
import javax.mail.BodyPart;
import javax.mail.MessagingException;
import javax.mail.Multipart;
import javax.mail.Session;
import javax.mail.internet.MimeBodyPart;
import javax.mail.internet.MimeMessage;
import javax.mail.internet.MimeMultipart;
import javax.mail.util.ByteArrayDataSource;
import junit.framework.TestCase;
public class mimeTest extends TestCase {
public void testPartialMulitpartMessage() throws MessagingException, IOException
{
Properties props = new Properties();
Session session = Session.getInstance(props, null);
String testMsg1 = "test";
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
// Step 1 - Create first MIME message
MimeMessage mesg = new MimeMessage(session);
Multipart mp = new MimeMultipart("mixed");
//create a child part
BodyPart bodyPart = new MimeBodyPart();
bodyPart.setContent(testMsg1, "application/x-special");
bodyPart.setHeader("Content-Length", String.valueOf(testMsg1.length()));
DataSource ds = new ByteArrayDataSource(testMsg1, "application/x-special");
bodyPart.setDataHandler(new DataHandler(ds));
bodyPart.setHeader("Content-Transfer-Encoding", "8bit");
// Add the child part to the multipart
mp.addBodyPart(bodyPart);
// Put the MultiPart into the Message
mesg.setContent(mp);
// Step 2 - write to a stream
mesg.writeTo(byteArrayOutputStream);
byte bytes[] = byteArrayOutputStream.toByteArray();
ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(bytes, 0, 10);
BufferedInputStream bufferedInputStream = new BufferedInputStream(byteArrayInputStream);
boolean thrown = false;
try
{
//Why does this not throw a messageexception.
MimeMessage mesg2 = new MimeMessage(session, bufferedInputStream);
}
catch(MessagingException me){
thrown = true;
}
if(!thrown) {
assertTrue("Expected exception not thrown.", false);
}
}
public void testMulitpleMulitpartMessages() throws MessagingException, IOException {
Properties props = new Properties();
Session session = Session.getInstance(props, null);
String testMsg1 = "test";
String testMsg2 = "test1";
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
// Step 1 - Create first MIME message
MimeMessage mesg = new MimeMessage(session);
Multipart mp = new MimeMultipart("mixed");
//create a child part
BodyPart bodyPart = new MimeBodyPart();
bodyPart.setContent(testMsg1, "application/x-special");
bodyPart.setHeader("Content-Length", String.valueOf(testMsg1.length()));
DataSource ds = new ByteArrayDataSource(testMsg1, "application/x-special");
bodyPart.setDataHandler(new DataHandler(ds));
bodyPart.setHeader("Content-Transfer-Encoding", "8bit");
// Add the child part to the multipart
mp.addBodyPart(bodyPart);
// Put the MultiPart into the Message
mesg.setContent(mp);
// Step 2 - write to a stream
mesg.writeTo(byteArrayOutputStream);
// Step 3 - Create second MIME message
MimeMessage mesg2 = new MimeMessage(session);
mp = new MimeMultipart("mixed");
//create a child part
bodyPart = new MimeBodyPart();
bodyPart.setContent(testMsg2, "application/x-special");
bodyPart.setHeader("Content-Length", String.valueOf(testMsg2.length()));
ds = new ByteArrayDataSource(testMsg2, "application/x-special");
bodyPart.setDataHandler(new DataHandler(ds));
bodyPart.setHeader("Content-Transfer-Encoding", "8bit");
// Add the child part to the multipart
mp.addBodyPart(bodyPart);
// Put the MultiPart into the Message
mesg2.setContent(mp);
// Step 4 - write to the same stream
mesg2.writeTo(byteArrayOutputStream);
// Step 6 - read the two messages back
ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(byteArrayOutputStream.toByteArray());
BufferedInputStream bufferedInputStream = new BufferedInputStream(byteArrayInputStream);
List<MimeMessage> listMessages = new ArrayList<MimeMessage>();
while (bufferedInputStream.available() > 0) {
//http://java.sun.com/products/javamail/javadocs/javax/mail/internet/MimeMessage.html#MimeMessage(javax.mail.Session,%20java.io.InputStream)
//The InputStream will be left positioned at the end of the data for the message.
//WHY does this not work? It reads the whole stream.
mesg = new MimeMessage(session, bufferedInputStream);
//output the message
listMessages.add(mesg);
}
assertEquals(2, listMessages.size());
assertTrue(listMessages.get(0).equals(mesg));
assertTrue(listMessages.get(1).equals(mesg2));
}
}