Mapleton

Author: xiao cheng

CMakeLists.txt

@@ -13,6 +13,7 @@ if(Boost_FOUND)
 
     add_subdirectory(googletest)
     add_subdirectory(Singleton)
+    add_subdirectory(Mapleton)
     add_subdirectory(DependencyInjection)
     add_subdirectory(BuildPattern)
     add_subdirectory(Proto)

Mapleton/CMakeLists.txt

@@ -0,0 +1,18 @@
+cmake_minimum_required(VERSION 3.8)
+
+project(Mapleton)
+
+include_directories(${Boost_INCLUDE_DIRS})
+
+add_executable(${PROJECT_NAME} Mapleton.cpp)
+
+target_link_libraries(${PROJECT_NAME} PUBLIC 
+ gtest_main
+ ${Boost_LIBRARIES}
+ )
+
+ add_test(
+     NAME ${PROJECT_NAME}
+     COMMAND ${PROJECT_NAME}
+ )
+ install(TARGETS ${PROJECT_NAME} RUNTIME DESTINATION ../bin)

Mapleton/Mapleton.cpp

@@ -0,0 +1,59 @@
+#include <iostream>
+#include <string>
+#include <map>
+
+class Mapleton {
+public:
+    // Returns a reference to static instance of this class
+    // based on provided string identifier
+    static Mapleton& instance(const std::string& id) {
+        static std::map<std::string, Mapleton> instances;
+        auto it = instances.find(id);
+
+        if (it != instances.end()) {
+            return it->second;
+        }
+
+        Mapleton instance(id);
+        auto insertIt = instances.emplace(id, std::move(instance));
+        return insertIt.first->second;   
+    }
+    
+    // The big five. We don't want singleton instances to be
+    // copyable nor movable. They should always be accessed with
+    // ::instance.
+    ~Mapleton() = default;
+    //Mapleton(Mapleton&) = delete;
+    //Mapleton(Mapleton&&) = delete;
+    //Mapleton(const Mapleton&) = delete;
+    //Mapleton(const Mapleton&&) = delete;
+    //Mapleton& operator=(const Mapleton&) = delete;
+    //Mapleton& operator=(const Mapleton&&) = delete;
+    
+    void say_hello_id() {
+        std::cout << "Hello " << id << std::endl;   
+        std::cout << "Number is " << i << std::endl;
+    }
+    
+    void increment() {
+        i++;
+    }
+    
+private:
+    Mapleton(const std::string& id) : id{id}, i{0} {};
+    std::string id;
+    int i;
+};
+
+int main()
+{
+    auto& minst = Mapleton::instance("mapleton!");
+    minst.say_hello_id();
+    minst.increment();
+    
+    auto& mins2 = Mapleton::instance("mapleton!");
+    mins2.say_hello_id();
+    
+    auto& mins3 = Mapleton::instance("PLOO");
+    mins3.say_hello_id();
+}