Java

Enumerate the Header Fields of an Email

Demonstrates the read-only Chilkat Email.NumHeaderFields property together with GetHeaderFieldName and GetHeaderFieldValue to enumerate every header field. Indexing is zero-based, so fields run from 0 to NumHeaderFields - 1. Repeated header fields (a field name that appears more than once) are counted separately. This example builds a small email and prints each header field.

Background: A header field is a single Name: value line at the top of a MIME message. The same field name can legitimately appear multiple times — for example, a message can carry several Received lines, one added by each mail server it passed through. That is why enumerating by index (rather than looking up by name) matters: it lets you see every occurrence in the order it appears.

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Java

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[])
  {
    //  Demonstrates the read-only Email.NumHeaderFields property and enumerating each
    //  header field by zero-based index using GetHeaderFieldName and GetHeaderFieldValue.

    CkEmail email = new CkEmail();
    email.put_Subject("Header field enumeration");
    email.put_From("mary@example.com");
    email.AddTo("Joe","joe@example.com");

    int n = email.get_NumHeaderFields();
    System.out.println("NumHeaderFields = " + n);

    int i;
    for (i = 0; i <= n - 1; i++) {
        System.out.println(email.getHeaderFieldName(i) + ": " + email.getHeaderFieldValue(i));
        }
  }
}