@Override
  public void validateMessagePayload(
      Message receivedMessage,
      Message controlMessage,
      XmlMessageValidationContext validationContext,
      TestContext context)
      throws ValidationException {
    log.info("Start XML message validation");

    try {
      if (validationContext.isSchemaValidationEnabled()) {
        validateXMLSchema(receivedMessage, validationContext);
        validateDTD(validationContext.getDTDResource(), receivedMessage);
      }

      validateNamespaces(validationContext.getControlNamespaces(), receivedMessage);
      validateMessageContent(receivedMessage, controlMessage, validationContext, context);

      if (controlMessage != null) {
        Assert.isTrue(
            controlMessage.getHeaderData().size() <= receivedMessage.getHeaderData().size(),
            "Failed to validate header data XML fragments - found "
                + receivedMessage.getHeaderData().size()
                + " header fragments, expected "
                + controlMessage.getHeaderData().size());

        for (int i = 0; i < controlMessage.getHeaderData().size(); i++) {
          validateXmlHeaderFragment(
              receivedMessage.getHeaderData().get(i),
              controlMessage.getHeaderData().get(i),
              validationContext,
              context);
        }
      }

      log.info("XML message validation successful: All values OK");
    } catch (ClassCastException e) {
      throw new CitrusRuntimeException(e);
    } catch (DOMException e) {
      throw new CitrusRuntimeException(e);
    } catch (LSException e) {
      throw new CitrusRuntimeException(e);
    } catch (IllegalArgumentException e) {
      log.error(
          "Failed to validate:\n" + XMLUtils.prettyPrint(receivedMessage.getPayload(String.class)));
      throw new ValidationException("Validation failed:", e);
    } catch (ValidationException ex) {
      log.error(
          "Failed to validate:\n" + XMLUtils.prettyPrint(receivedMessage.getPayload(String.class)));
      throw ex;
    }
  }
  /**
   * Validates XML header fragment data.
   *
   * @param receivedHeaderData
   * @param controlHeaderData
   * @param validationContext
   * @param context
   */
  private void validateXmlHeaderFragment(
      String receivedHeaderData,
      String controlHeaderData,
      XmlMessageValidationContext validationContext,
      TestContext context) {
    log.info("Start XML header data validation ...");

    Document received = XMLUtils.parseMessagePayload(receivedHeaderData);
    Document source = XMLUtils.parseMessagePayload(controlHeaderData);

    XMLUtils.stripWhitespaceNodes(received);
    XMLUtils.stripWhitespaceNodes(source);

    if (log.isDebugEnabled()) {
      log.debug("Received header data:\n" + XMLUtils.serialize(received));
      log.debug("Control header data:\n" + XMLUtils.serialize(source));
    }

    validateXmlTree(
        received,
        source,
        validationContext,
        namespaceContextBuilder.buildContext(
            new DefaultMessage(receivedHeaderData), validationContext.getNamespaces()),
        context);
  }
  /**
   * Validate message payloads by comparing to a control message.
   *
   * @param receivedMessage
   * @param validationContext
   * @param context
   */
  protected void validateMessageContent(
      Message receivedMessage,
      Message controlMessage,
      XmlMessageValidationContext validationContext,
      TestContext context) {
    if (controlMessage == null || controlMessage.getPayload() == null) {
      log.info("Skip message payload validation as no control message was defined");
      return;
    }

    if (!(controlMessage.getPayload() instanceof String)) {
      throw new IllegalArgumentException(
          "DomXmlMessageValidator does only support message payload of type String, "
              + "but was "
              + controlMessage.getPayload().getClass());
    }

    String controlMessagePayload = controlMessage.getPayload(String.class);

    if (receivedMessage.getPayload() == null
        || !StringUtils.hasText(receivedMessage.getPayload(String.class))) {
      Assert.isTrue(
          !StringUtils.hasText(controlMessagePayload),
          "Unable to validate message payload - received message payload was empty, control message payload is not");
      return;
    } else if (!StringUtils.hasText(controlMessagePayload)) {
      return;
    }

    log.info("Start XML tree validation ...");

    Document received = XMLUtils.parseMessagePayload(receivedMessage.getPayload(String.class));
    Document source = XMLUtils.parseMessagePayload(controlMessagePayload);

    XMLUtils.stripWhitespaceNodes(received);
    XMLUtils.stripWhitespaceNodes(source);

    if (log.isDebugEnabled()) {
      log.debug("Received message:\n" + XMLUtils.serialize(received));
      log.debug("Control message:\n" + XMLUtils.serialize(source));
    }

    validateXmlTree(
        received,
        source,
        validationContext,
        namespaceContextBuilder.buildContext(receivedMessage, validationContext.getNamespaces()),
        context);
  }
  /**
   * Handle attribute node during validation.
   *
   * @param receivedElement
   * @param receivedAttribute
   * @param sourceElement
   * @param validationContext
   */
  private void doAttribute(
      Node receivedElement,
      Node receivedAttribute,
      Node sourceElement,
      XmlMessageValidationContext validationContext,
      NamespaceContext namespaceContext,
      TestContext context) {
    if (receivedAttribute.getNodeName().startsWith(XMLConstants.XMLNS_ATTRIBUTE)) {
      return;
    }

    String receivedAttributeName = receivedAttribute.getLocalName();

    if (log.isDebugEnabled()) {
      log.debug(
          "Validating attribute: "
              + receivedAttributeName
              + " ("
              + receivedAttribute.getNamespaceURI()
              + ")");
    }

    NamedNodeMap sourceAttributes = sourceElement.getAttributes();
    Node sourceAttribute =
        sourceAttributes.getNamedItemNS(receivedAttribute.getNamespaceURI(), receivedAttributeName);

    Assert.isTrue(
        sourceAttribute != null,
        "Attribute validation failed for element '"
            + receivedElement.getLocalName()
            + "', unknown attribute "
            + receivedAttributeName
            + " ("
            + receivedAttribute.getNamespaceURI()
            + ")");

    if (XmlValidationUtils.isAttributeIgnored(
        receivedElement,
        receivedAttribute,
        sourceAttribute,
        validationContext.getIgnoreExpressions(),
        namespaceContext)) {
      return;
    }

    String receivedValue = receivedAttribute.getNodeValue();
    String sourceValue = sourceAttribute.getNodeValue();
    if (isValidationMatcherExpression(sourceAttribute)) {
      ValidationMatcherUtils.resolveValidationMatcher(
          sourceAttribute.getNodeName(),
          receivedAttribute.getNodeValue().trim(),
          sourceAttribute.getNodeValue().trim(),
          context);
    } else if (receivedValue.contains(":") && sourceValue.contains(":")) {
      doNamespaceQualifiedAttributeValidation(
          receivedElement, receivedAttribute, sourceElement, sourceAttribute);
    } else {
      Assert.isTrue(
          receivedValue.equals(sourceValue),
          ValidationUtils.buildValueMismatchErrorMessage(
              "Values not equal for attribute '" + receivedAttributeName + "'",
              sourceValue,
              receivedValue));
    }

    if (log.isDebugEnabled()) {
      log.debug("Attribute '" + receivedAttributeName + "'='" + receivedValue + "': OK");
    }
  }
  /**
   * Handle element node.
   *
   * @param received
   * @param source
   * @param validationContext
   */
  private void doElement(
      Node received,
      Node source,
      XmlMessageValidationContext validationContext,
      NamespaceContext namespaceContext,
      TestContext context) {

    doElementNameValidation(received, source);

    doElementNamespaceValidation(received, source);

    // check if element is ignored either by xpath or by ignore placeholder in source message
    if (XmlValidationUtils.isElementIgnored(
        source, received, validationContext.getIgnoreExpressions(), namespaceContext)) {
      return;
    }

    // work on attributes
    if (log.isDebugEnabled()) {
      log.debug("Validating attributes for element: " + received.getLocalName());
    }
    NamedNodeMap receivedAttr = received.getAttributes();
    NamedNodeMap sourceAttr = source.getAttributes();

    Assert.isTrue(
        countAttributes(receivedAttr) == countAttributes(sourceAttr),
        ValidationUtils.buildValueMismatchErrorMessage(
            "Number of attributes not equal for element '" + received.getLocalName() + "'",
            countAttributes(sourceAttr),
            countAttributes(receivedAttr)));

    for (int i = 0; i < receivedAttr.getLength(); i++) {
      doAttribute(
          received, receivedAttr.item(i), source, validationContext, namespaceContext, context);
    }

    // check if validation matcher on element is specified
    if (isValidationMatcherExpression(source)) {
      ValidationMatcherUtils.resolveValidationMatcher(
          source.getNodeName(),
          received.getFirstChild().getNodeValue().trim(),
          source.getFirstChild().getNodeValue().trim(),
          context);
      return;
    }

    // work on child nodes
    NodeList receivedChilds = received.getChildNodes();
    NodeList sourceChilds = source.getChildNodes();

    Assert.isTrue(
        receivedChilds.getLength() == sourceChilds.getLength(),
        ValidationUtils.buildValueMismatchErrorMessage(
            "Number of child elements not equal for element '" + received.getLocalName() + "'",
            sourceChilds.getLength(),
            receivedChilds.getLength()));

    for (int i = 0; i < receivedChilds.getLength(); i++) {
      this.validateXmlTree(
          receivedChilds.item(i),
          sourceChilds.item(i),
          validationContext,
          namespaceContext,
          context);
    }

    if (log.isDebugEnabled()) {
      log.debug(
          "Validation successful for element: "
              + received.getLocalName()
              + " ("
              + received.getNamespaceURI()
              + ")");
    }
  }
  /**
   * Validate message with a XML schema.
   *
   * @param receivedMessage
   * @param validationContext
   */
  protected void validateXMLSchema(
      Message receivedMessage, XmlMessageValidationContext validationContext) {
    if (receivedMessage.getPayload() == null
        || !StringUtils.hasText(receivedMessage.getPayload(String.class))) {
      return;
    }

    try {
      Document doc = XMLUtils.parseMessagePayload(receivedMessage.getPayload(String.class));

      if (!StringUtils.hasText(doc.getFirstChild().getNamespaceURI())) {
        return;
      }

      log.info("Starting XML schema validation ...");

      XmlValidator validator = null;
      XsdSchemaRepository schemaRepository = null;
      if (validationContext.getSchema() != null) {
        validator =
            applicationContext
                .getBean(validationContext.getSchema(), XsdSchema.class)
                .createValidator();
      } else if (validationContext.getSchemaRepository() != null) {
        schemaRepository =
            applicationContext.getBean(
                validationContext.getSchemaRepository(), XsdSchemaRepository.class);
      } else if (schemaRepositories.size() == 1) {
        schemaRepository = schemaRepositories.get(0);
      } else if (schemaRepositories.size() > 0) {
        for (XsdSchemaRepository repository : schemaRepositories) {
          if (repository.canValidate(doc)) {
            schemaRepository = repository;
          }
        }

        if (schemaRepository == null) {
          throw new CitrusRuntimeException(
              String.format(
                  "Failed to find proper schema repository in Spring bean context for validating element '%s(%s)'",
                  doc.getFirstChild().getLocalName(), doc.getFirstChild().getNamespaceURI()));
        }
      } else {
        log.warn(
            "Neither schema instance nor schema repository defined - skipping XML schema validation");
        return;
      }

      if (schemaRepository != null) {
        if (!schemaRepository.canValidate(doc)) {
          throw new CitrusRuntimeException(
              String.format(
                  "Unable to find proper XML schema definition for element '%s(%s)' in schema repository '%s'",
                  doc.getFirstChild().getLocalName(),
                  doc.getFirstChild().getNamespaceURI(),
                  schemaRepository.getName()));
        }

        List<Resource> schemas = new ArrayList<>();
        for (XsdSchema xsdSchema : schemaRepository.getSchemas()) {
          if (xsdSchema instanceof XsdSchemaCollection) {
            for (Resource resource : ((XsdSchemaCollection) xsdSchema).getSchemaResources()) {
              schemas.add(resource);
            }
          } else if (xsdSchema instanceof WsdlXsdSchema) {
            for (Resource resource : ((WsdlXsdSchema) xsdSchema).getSchemaResources()) {
              schemas.add(resource);
            }
          } else {
            synchronized (transformerFactory) {
              ByteArrayOutputStream bos = new ByteArrayOutputStream();
              try {
                transformerFactory
                    .newTransformer()
                    .transform(xsdSchema.getSource(), new StreamResult(bos));
              } catch (TransformerException e) {
                throw new CitrusRuntimeException(
                    "Failed to read schema " + xsdSchema.getTargetNamespace(), e);
              }
              schemas.add(new ByteArrayResource(bos.toByteArray()));
            }
          }
        }

        validator =
            XmlValidatorFactory.createValidator(
                schemas.toArray(new Resource[schemas.size()]), WsdlXsdSchema.W3C_XML_SCHEMA_NS_URI);
      }

      SAXParseException[] results = validator.validate(new DOMSource(doc));
      if (results.length == 0) {
        log.info("Schema of received XML validated OK");
      } else {
        log.error(
            "Schema validation failed for message:\n"
                + XMLUtils.prettyPrint(receivedMessage.getPayload(String.class)));

        // Report all parsing errors
        log.debug("Found " + results.length + " schema validation errors");
        StringBuilder errors = new StringBuilder();
        for (SAXParseException e : results) {
          errors.append(e.toString());
          errors.append("\n");
        }
        log.debug(errors.toString());

        throw new ValidationException("Schema validation failed:", results[0]);
      }
    } catch (IOException e) {
      throw new CitrusRuntimeException(e);
    } catch (SAXException e) {
      throw new CitrusRuntimeException(e);
    }
  }