adapter_pattern_example.cpp

Demonstrates the adapter pattern for uniform pointer-like access.

Demonstrates the adapter pattern for uniform pointer-like access.Shows wrapping raw values, shared_ptr, and unique_ptr with adapters that provide a unified access interface regardless of ownership model.

See also

kcenon::common::adapter

kcenon::common::adapter_traits

// BSD 3-Clause License
// Copyright (c) 2021-2025, 🍀☀🌕🌥 🌊
// See the LICENSE file in the project root for full license information.
 
 
#include <kcenon/common/adapters/adapter.h>
 
#include <iostream>
#include <memory>
#include <string>
 
using namespace kcenon::common;
using namespace kcenon::common::adapters;
 
// A sample service class
class DataService
{
public:
    explicit DataService(std::string name) : name_(std::move(name)) {}
 
    std::string get_name() const { return name_; }
    void process() { std::cout << "      " << name_ << " processing data...\n"; }
 
private:
    std::string name_;
};
 
// Generic function that works with any adapter
template <typename T>
void use_service(const adapter<T>& svc)
{
    std::cout << "   Pointer valid: " << (svc.get() != nullptr ? "true" : "false") << "\n";
    svc->process();
}
 
int main()
{
    std::cout << "=== Adapter Pattern Example ===\n\n";
 
    // 1. Wrap a shared_ptr
    std::cout << "1. Shared pointer adapter:\n";
    {
        auto service = std::make_shared<DataService>("SharedService");
        auto adapted = adapter(service);
 
        std::cout << "   Name via ->: " << adapted->get_name() << "\n";
        use_service(adapted);
    }
 
    // 2. Wrap a unique_ptr
    std::cout << "\n2. Unique pointer adapter:\n";
    {
        auto service = std::make_unique<DataService>("UniqueService");
        auto adapted = adapter(std::move(service));
 
        std::cout << "   Name via ->: " << adapted->get_name() << "\n";
        std::cout << "   Raw ptr: " << (adapted.get() != nullptr ? "valid" : "null") << "\n";
    }
 
    // 3. Use make_shared_adapter helper
    std::cout << "\n3. make_shared_adapter helper:\n";
    {
        auto adapted = make_shared_adapter<DataService>("FactoryService");
        std::cout << "   Name: " << adapted->get_name() << "\n";
        adapted->process();
    }
 
    // 4. Adapter traits inspection
    std::cout << "\n4. Adapter traits:\n";
    {
        using shared_traits = adapter_traits<std::shared_ptr<DataService>>;
        using unique_traits = adapter_traits<std::unique_ptr<DataService>>;
 
        std::cout << "   shared_ptr is_smart_pointer: "
                  << (shared_traits::is_smart_pointer ? "true" : "false") << "\n";
        std::cout << "   shared_ptr supports_weak: "
                  << (shared_traits::supports_weak ? "true" : "false") << "\n";
        std::cout << "   unique_ptr is_smart_pointer: "
                  << (unique_traits::is_smart_pointer ? "true" : "false") << "\n";
        std::cout << "   unique_ptr supports_weak: "
                  << (unique_traits::supports_weak ? "true" : "false") << "\n";
    }
 
    std::cout << "\nDone.\n";
    return 0;
}