add logger example

Author: 7bitcoder

Examples/Logger.cpp

@@ -0,0 +1,83 @@
+#include <SevenBit/DI.hpp>
+#include <filesystem>
+#include <fstream>
+#include <iostream>
+
+using namespace sb::di;
+
+struct ILogger
+{
+    virtual void log(const std::string &message) = 0;
+
+    virtual ~ILogger() = default;
+};
+
+struct StdLogger final : ILogger
+{
+    void log(const std::string &message) override { std::cout << message << std::endl; }
+};
+
+struct FileLogger final : ILogger
+{
+    std::ofstream logFile{"log.txt"};
+
+    void log(const std::string &message) override { logFile << message << std::endl; }
+};
+
+struct VoidLogger final : ILogger
+{
+    void log(const std::string &message) override {}
+};
+
+class Application
+{
+    ILogger &_logger;
+
+  public:
+    explicit Application(ILogger &logger) : _logger(logger) {}
+
+    int run()
+    {
+        _logger.log("Initializing");
+        init();
+        _logger.log("Processing");
+        process();
+        _logger.log("Finalizing");
+        finalize();
+        return 0;
+    }
+
+  private:
+    void init() {}
+    void process() {}
+    void finalize() {}
+};
+
+void addLogger(const std::string_view loggerName, ServiceCollection &services)
+{
+    if (loggerName == "fileLogger")
+    {
+        services.addSingleton<ILogger, FileLogger>();
+    }
+    else if (loggerName == "voidLogger")
+    {
+        services.addSingleton<ILogger, VoidLogger>();
+    }
+    else
+    {
+        services.addSingleton<ILogger, StdLogger>();
+    }
+}
+
+int main(int argc, char *argv[])
+{
+    ServiceCollection services;
+    const auto loggerName = argc > 1 ? argv[1] : "stdLogger";
+    addLogger(loggerName, services);
+    services.addSingleton<Application>();
+
+    ServiceProvider provider = services.buildServiceProvider();
+
+    auto &app = provider.getService<Application>();
+    return app.run();
+}

Tests/E2E/Examples/expected_test_data.json

@@ -10,6 +10,7 @@
   "InjectingServices": "^actionA, actionB executed.",
   "InjectionRules": "",
   "KeyedServices": "^action, action, action executed.",
+  "Logger": "^Initializing\nProcessing\nFinalizing",
   "RegisterUtilityClass": "^actionA, actionB executed.",
   "SeparateImplementation": "^Hello from service.",
   "ServicesLifeTime": "\nSingletons comparison\nrootProvider\\s+== rootProvider:\\s+1\nrootProvider\\s+== scopedProvider:\\s+1\nscopedProvider\\s+== scopedProvider:\\s+1\n\nScoped comparison\nrootProvider\\s+== rootProvider:\\s+1\nrootProvider\\s+== scopedProvider:\\s+0\nscopedProvider\\s+== scopedProvider:\\s+1\n\nTransient comparison\nrootProvider\\s+== rootProvider:\\s+0\nrootProvider\\s+== scopedProvider:\\s+0\nscopedProvider\\s+== scopedProvider:\\s+0\n",