import javax.mail.*;
import javax.mail.internet.*;

// Configuration below...

type = "imap" // (or pop3)
host = "domain.com"
user = "username"
pass = "password"
deleteOn = "Undelivered Mail Returned to Sender" // This is the subject line to search for.  Any messages matching will be deleted.
testRun = true;  // if this is true, it will only make 5 passes and then exit.
passes = 5;	// Number of passes to make before closing the connection and committing changes

// End configuration...

moreAvailable = true;
progStart = System.currentTimeMillis();

while(moreAvailable) {

// -- Get hold of the default session --
Properties props = System.getProperties();
Session session = Session.getDefaultInstance(props, null);

// -- Get hold of a POP3 message store, and connect to it --
Store store = session.getStore(type);
store.connect(host, user, pass);

// -- Try to get hold of the default folder --
Folder folder = store.getDefaultFolder();
if(folder == null)
	throw new Exception("No default folder");

// -- ...and its INBOX --
folder = folder.getFolder("INBOX");
if(folder == null)
	throw new Exception("No " + type + " INBOX");

// -- Open the folder for read only --
folder.open(Folder.READ_WRITE);

// -- Get the message wrappers and process them --
int total = folder.getMessageCount();

if(total < 700) {
	moreAvailable = false;
}


println "Total messages: " + total;
long start = System.currentTimeMillis();
long lastTime = System.currentTimeMillis();
int testCount = 0;
int page = 100;
for(i in 0..(total/page)) {
	println(" Elapsed Time: " + (System.currentTimeMillis() - start) + " MS");
	println("Deleting messages[" + (total - (page * (i + 1))) + ", " + (total - (page * i)) + "]");
	messages = folder.getMessages(total - (page * (i + 1)), total - (page * i));
	for(m in messages) {
		if(m.getSubject().equals(deleteOn)) {
			print "."
			m.setFlag(Flags.Flag.DELETED, true);
		}
	}
	println ""
	
	testCount++;
	if(testRun && testCount > 5) {
		break;
	}
	print "Deletion took: " + (System.currentTimeMillis() - lastTime) + " MS";
	lastTime = System.currentTimeMillis();
	
}
println "Committing changes...";

folder.expunge();
folder.close(true);
store.close();

println("Pass took: " + (System.currentTimeMillis() - start) + " MS");

}

println("Total time to cleanup: " + (System.currentTimeMillis() - progStart) + " MS");