POP3: Download Most Recent Email (method 1)

How to ready the N most recent email from a POP3 server.

The POP3 protocol does not provide the ability to request the most recent email, nor does it provide the ability to download email based on read/unread status or any other criteria. The design principle behind POP3 is that it is a temporary holding store for incoming email and email clients or other applications will transfer email from the POP3 server to a local persistent store where it will be managed. Therefore, POP3 does not provide sophisticated functionality (as opposed to IMAP which has the opposite design philosophy: that email is maintained and organized on the server).

This example shows one possible way to retrieve the N most recent emails from a POP3 server. It downloads the headers into a bundle object, then sorts the bundle by date, and finally retrieves the most recent emails by UIDL.

Another alternative is to download the UIDL list and then assume that the 1st N UIDLs are the most recent.

Download Chilkat Java Library

import com.chilkatsoft.*;

public class ChilkatExample {

  static {
    try {
        System.loadLibrary("chilkat");
    } catch (UnsatisfiedLinkError e) {
      System.err.println("Native code library failed to load.\n" + e);
      System.exit(1);
    }
  }

  public static void main(String argv[])
  {
    //  The mailman object is used for receiving (POP3)
    //  and sending (SMTP) email.
    CkMailMan mailman = new CkMailMan();

    //  Any string argument automatically begins the 30-day trial.
    boolean success;
    success = mailman.UnlockComponent("30-day trial");
    if (success != true) {
        System.out.println("Component unlock failed");
        return;
    }

    //  Set the POP3 server's hostname
    mailman.put_MailHost("mail.chilkatsoft.com");

    //  Set the POP3 login/password.
    mailman.put_PopUsername("admin@chilkatsoft.com");
    mailman.put_PopPassword("*myPassword5*");

    CkEmailBundle bundle;
    //  Read mail headers and one line of the body.
    bundle = mailman.GetAllHeaders(1);

    if (bundle == null ) {
        System.out.println(mailman.lastErrorText());
        return;
    }

    //  Sort the bundle by date
    boolean ascending;
    ascending = false;
    bundle.SortByDate(ascending);

    //  Get the 10 most recent UIDLs
    CkStringArray saUidls = new CkStringArray();
    int i;
    int n;
    n = bundle.get_MessageCount();
    if (n > 10) {
        n = 10;
    }

    CkEmail email;
    for (i = 0; i <= n - 1; i++) {
        email = bundle.GetEmail(i);
        saUidls.Append(email.uidl());

    }

    //  Download in full the 10 most recent emails:
    CkEmailBundle bundle2;

    bundle2 = mailman.FetchMultiple(saUidls);
    if (bundle2 == null ) {
        System.out.println(mailman.lastErrorText());
        return;
    }

    for (i = 0; i <= bundle2.get_MessageCount() - 1; i++) {
        email = bundle2.GetEmail(i);
        System.out.println(email.ck_from());
        System.out.println(email.subject());
        System.out.println("----");

    }

  }
}