LoadingElementConfig.cpp

This example demonstrates how to load the configuration of a skill element.

#include "MyQuery.hpp"
 
#include <xentara/config/Context.hpp>
#include <xentara/config/Errors.hpp>
#include <xentara/model/ElementCategory.hpp>
#include <xentara/skill/Element.hpp>
 
#include <xentara/utils/core/Uuid.hpp>
#include <xentara/utils/json/decoder/Errors.hpp>
#include <xentara/utils/json/decoder/Object.hpp>
 
#include <memory>
#include <string_view>
 
//#############################################
// Declaration of MyElement class
//#############################################
 
using namespace std::literals;
using namespace xentara::literals;
 
// This class represents a MyElement
class MyElement : public xentara::skill::Element
{
public:
    // This type contains the meta information for the element type
    using Class = xentara::skill::Element::ConcreteClass<"MyElement", "b465bbcc-be55-4087-9458-58eaebfd3250"_uuid, "my element">;
 
    auto category() const noexcept -> model::ElementCategory final
    {
        return model::ElementCategory::SpecialPurpose;
    }
 
protected:
    auto load(xentara::utils::json::decoder::Object &jsonObject, xentara::config::Context &context) -> void override;
 
private:
    // These are some configuration parameters
    int _minimum { 0 };
    int _maximum { 100 };
    double _divisor { 1.0 };
 
    // This is some reference to another object
    std::weak_ptr<MyQuery> _query;
};
 
//#############################################
// Implementation of MyElement class
//#############################################
 
auto MyElement::load(xentara::utils::json::decoder::Object &jsonObject, xentara::config::Context &context) -> void
{
    // Loop through all the members of the JSON object
    for (auto && [name, value] : jsonObject)
    {
        // Check the different keys
        if (name == "minimum"sv)
        {
            _minimum = value.toNumber<int>();
        }
        else if (name == "maximum"sv)
        {
            _maximum = value.asNumber<int>();
        }
        else if (name == "divisor"sv)
        {
            _divisor = value.asNumber<double>();
 
            // Check the validity of this particular parameter
            if (_divisor == 0)
            {
                utils::json::decoder::throwWithLocation(value,
                    "the divisor must not be 0");
            }
        }
        else if (name == "query"sv)
        {
            // Submit a request to resolve the query to the resolver
            resolver.submit(_query);
        }
        else
        {
            // Throw an error for unknown parameters
            xentara::config::throwUnknownParameterError(name);
        }
    }
 
    // Check the consistency of all the loaded parameters
    if (_maximum <= _minimum)
    {
        utils::json::decoder::throwWithLocation(jsonObject,
            "the maximum must be strictly greater than the minimum");
    }
}