An ArrayReporter object that can be used in the xparse method is used to store information about the xparse method. ArrayReporter saves information in text form at alert / error levels that can be further processed by the program.

package cz.syntea.skp.slp2.lp.epemog;

import cz.syntea.common.sys.ArrayReporter;
import cz.syntea.common.sys.Report;
import cz.syntea.common.xml.KXmlUtils;
import cz.syntea.xd.XDDocument;
import cz.syntea.xd.XDFactory;
import cz.syntea.xd.XDPool;
import org.w3c.dom.Element;
import java.io.File;

public class XdefValidate {

    public static void main(String[] args) {
        // creation of xdPool from xdefinition
        XDPool xdPool = XDFactory.genXDPool(null, "C:/xdef/validation.xdef", null);
        // obtain xdDocument from xdPool for one validation
        XDDocument xdDocument = xdPool.createXDDocument();
        // validation of the file content. If the content is not valid, it throws an error
        ArrayReporter reporter = new ArrayReporter();
        Element result = xdDocument.xparse(new File("C:/data/document.xml"), reporter);
        if (reporter.errorWarnings()) {
            // print the protocol from the validation
            Report rep;
            while ((rep = reporter.getReport()) != null) {
                System.err.println(rep.toString());
            }
            System.exit(-1);
        }
        // print the input xml
        System.out.printf(KXmlUtils.nodeToString(result, true));
    }
}

External methods and declared methods are Java code, the script is a custom xdefinition X-Script script. External methods are declared in Java classes in external files, and declared methods are defined in the xdefinition file using the xd:declaration keyword. In the latter case, it is then necessary to declare the method signatures in the xdefinition header under the keyword xd:methods. In this way, it is also possible to declare types or variables. X-Script is also declared within xdefinition under the keyword xd:script. It can call up embedded xdefinition methods, external, and declared methods.

We add the xnode parameter XXNode to the external method signature, which represents the object representation of the node in the xml document that is currently being processed.

public static void myPrint(XXNode xnode, String output) {
  String lp = xnode.getXXElement().getAttribute("lp");
  System.out.printf("Info=%s; Licence plate=%s", output, lp);
}

The x-definitionParser contains a large number of data types that can be used to describe the attributes and values of a node, but in some cases, it is appropriate to define your own data type, whether for a special purpose or for clarity of the xdefinition itself. New data types are defined using the keyword xd:declarations

<xd:def
  xmlns:xd = "http://www.syntea.cz/xdef/2.0"
  xd:name	 = "Vehicles"
  xd:root = "Vehicles">

    <Vehicles>
        <Car xd:script    = "occurs 0.."
             Type         = "required carType()"
             LicencePlate = "required lp(7)" />
    </Vehicles>

  <xd:declaration>
    /* own type derived from another */
    type carType list('SEDAN', 'WAGON', 'HATCHBACK', 'SUV');
    /* own type from scratch */
    boolean lp(int len) {
      String text = getText();
      if (text.length() != len) {
        return error(text + " does not meet the conditions. " + len +
          " character are required.");
      }
      return true;
    }
  </xd:declaration>
</xd:def>

This fact must be considered when implementing external methods and during handover of parameters between the X-Definition and the external method in the Java class. The solution is to redefine the parameter type from int to long in the external java function.