Printing variable values in Java

Question

I've got an object which is a new MimeMessage called message and I want to find out what it's passing to my outgoing mail server. I however have no idea how one gets a variable like this printed out in Java. Here's some code:

private String sendConfirmationEmail (String to, String from, String subject, String body, boolean CCSender) {
 try
 {
 // String smtpHost = Properties.smtp;
 String smtpHost = Properties.smtp; 
 String fromAddress = from;
 String toAddress = to;
 Properties properties = System.getProperties();
 properties.put("mail.smtp.host", smtpHost);
 Session session = Session.getInstance(properties, null);
 MimeMessage message = new MimeMessage(session);
 message.setFrom(new InternetAddress(fromAddress));
 message.setRecipient(Message.RecipientType.TO,
 new InternetAddress(toAddress));
 if (CCSender) {
 message.setRecipient(Message.RecipientType.CC,
 new InternetAddress(from));
 }
 message.setSubject(subject);
 message.setText(body);
 System.out.println(message); <=== I want this to work!
 message.saveChanges();
 Transport.send(message);
 return "1:success";
 }
 catch(Exception e)
 {
 return "0:failure "+e.toString();
 }
 }

Any help would be much appreciated.

Thanks.

Answer 1

If it's a class you have control of, you override it's toString() method

If you have no control over it, you'll have to write a method like

String valueOf(Message message) {
 StringBuilder sb = new StringBuilder();
 sb.append(message.someValue());
 sb.append(message.someOtherValue());
 return sb.toString();
}

and use valueOf in your debug message

For MimeMessage, I'd rely on it having a toString implementation for its content

String valueOf(Message message) {
 return message.getContent().toString();
}

Answer 2

For MimeMessage, you can call message.writeTo(System.out);. You will probably want to do this after calling message.saveChanges() to ensure consistency.

Answer 3

You could create a decorator class implementing the base interface, and logging/printing everything returned by the wrapped class' toString() (or whatever other methods the base interface has).