Dictionary Exploration

The OnixS::FIX::Dictionary class exposes an interface to access information about the content of a specialized FIX dictionary or standard FIX messaging specification. This interface allows to obtain the types of a specific dictionary or standard FIX messages, and to explore the entire message structure, as well as to retrieve names of arbitrary fields by tag numbers.

Accessing Fields Information

The following members are present for basic field information manipulation:

• OnixS::FIX::Dictionary::tags returns a complete set of tags known to the specific version of FIX messaging specification of FIX dictionary.
• OnixS::FIX::Dictionary::fieldName returns the name of a field or a group by its tag number.
• OnixS::FIX::Dictionary::fieldType returns the type of a field by its tag number.
• OnixS::FIX::Dictionary::fieldNumber provides with an ability to get field number by its name.
• OnixS::FIX::Dictionary::validFieldValues exposes a set of valid values for a specific field.
• OnixS::FIX::Dictionary::fieldValueDescription returns the value description (if it exists) of the corresponding FIX field value.

Dictionary fix44(ProtocolVersion::FIX_44);
 
const Tag TagNumber = FIX44::Tags::Side;
const std::string TagName = fix44.fieldName(TagNumber);
const FieldValueTypes::Enum FieldType = fix44.fieldType(TagNumber);
 
std::cout << "Field " << TagName << "(" << TagNumber << ") has";
 
// Standard dictionaries do not retain field types.
// Dictionaries must be overridden and the 'type' attribute must be added
// to the 'Field' node in the FIX Dictionary XML file.
if(FieldType != FieldValueTypes::Unknown)
    std::cout << " type "
              << FieldValueTypes::toString(FieldType)
              << " and";
 
std::cout << " the following valid values:" << std::endl;
 
Dictionary::ValidFieldValues validFieldValues = fix44.validFieldValues(TagNumber);
 
for(const auto & validFieldValue : validFieldValues)
{
    std::cout << validFieldValue.value() << "(" << validFieldValue.description() << ")" << std::endl;
}

Note

Standard dictionaries do not retain field types. They must be overridden and the 'type' attribute must be added to the 'Field' node in the FIX Dictionary XML file. See Field value validation.

Exploring Dictionary Messages Structure

To explore message-related information, the following members are present:

• OnixS::FIX::Dictionary::messageTypes returns a collection of types of all messages available in the FIX message specification or FIX dictionary for which the class instance was created.
• OnixS::FIX::Dictionary::messageName finds the name of a message by its type.
• OnixS::FIX::Dictionary::messageFields returns information about all fields available in the specific message.

The following example demonstrates how fields, which make up a message, can be traversing.

void traverseFields(const Dictionary::FieldInfos& fields, int shift)
{
    std::string spaces(shift, ' ');
 
    for(const auto & fieldInfo : fields)
    {
        std::cout << spaces << fieldInfo.tag() << "(required=" << fieldInfo.isRequired() << ")" << std::endl;
        traverseFields(fieldInfo.childFields(), 2 + shift);
    }
}
 
void traverseMessages(const Dictionary& dictionary)
{
    Dictionary::MessageTypes messageTypes = dictionary.messageTypes();
 
    for(const auto & msgType : messageTypes)
    {
        std::cout << "Traversing " << dictionary.messageName(msgType) << "(msgType=" << msgType << ")" << std::endl;
        traverseFields(dictionary.messageFields(msgType), 0);
    }
}