(Java) Calculate HRMC IRMark

Demonstrates how to calculate an IRmark for an HMRC GovTalkMessage XML document.

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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[])
  {
    //  This example requires the Chilkat API to have been previously unlocked.
    //  See Global Unlock Sample for sample code.

    //  First build a sample (but incomplete) GovTalkMessage.
    //  You can replace this code with a call to LoadXml or LoadXmlFile..
    // 
    //  Note: The online tool at https://tools.chilkat.io/xmlCreate.cshtml
    //  can be used to generate XML code that creates a given XML document.
    CkXml xml = new CkXml();
    xml.put_Tag("GovTalkMessage");
    xml.AddAttribute("xmlns","http://www.govtalk.gov.uk/CM/envelope");
    xml.UpdateAttrAt("Body|Message",true,"xmlns","urn:g3.ge:dea:call:SendDocument:v1");
    xml.UpdateChildContent("Body|Message","................");

    //  This is the XML created:
    //  <?xml version="1.0" encoding="utf-8" ?>
    //  <GovTalkMessage xmlns="http://www.govtalk.gov.uk/CM/envelope">
    //      <Body>
    //          <Message xmlns="urn:g3.ge:dea:call:SendDocument:v1">................</Message>
    //      </Body>
    //  </GovTalkMessage>

    System.out.println(xml.getXml());

    //  Canonicalize the XML (using C14N)
    CkXmlDSig xdsig = new CkXmlDSig();
    boolean withComments = false;
    String canonXml = xdsig.canonicalizeXml(xml.getXml(),"C14N",withComments);

    //  Return the base64 SHA-1 HASH of the canonical XML.
    CkCrypt2 crypt = new CkCrypt2();
    crypt.put_HashAlgorithm("sha1");
    crypt.put_EncodingMode("base64");
    String irmark = crypt.hashStringENC(canonXml);

    System.out.println("IRMark = " + irmark);
  }
}