docs: public void checkForWellFormedMessageHeader(final Node node)
      {
          final boolean shouldGenerateInterfaces = Boolean.getBoolean(JAVA_GENERATE_INTERFACES);
  
          final EncodedDataType blockLengthType = (EncodedDataType)containedTypeByNameMap.get("blockLength");
          final EncodedDataType templateIdType = (EncodedDataType)containedTypeByNameMap.get("templateId");
          final EncodedDataType schemaIdType = (EncodedDataType)containedTypeByNameMap.get("schemaId");
          final EncodedDataType versionType = (EncodedDataType)containedTypeByNameMap.get("version");
  
          if (blockLengthType == null)
          {
              XmlSchemaParser.handleError(node, "composite for message header must have \"blockLength\"");
          }
          else if (!isUnsigned(blockLengthType.primitiveType()))
          {
              XmlSchemaParser.handleError(node, "\"blockLength\" must be unsigned");
          }
  
          validateHeaderField(node, "blockLength", blockLengthType, UINT16, shouldGenerateInterfaces);
          validateHeaderField(node, "templateId", templateIdType, UINT16, shouldGenerateInterfaces);
          validateHeaderField(node, "schemaId", schemaIdType, UINT16, shouldGenerateInterfaces);
          validateHeaderField(node, "version", versionType, UINT16, shouldGenerateInterfaces);
      }