What is "The Singleton Pattern: The Full Code" about?

The full singleton pattern project as real, browsable files, using the idiomatic thread-safe version in C++, TypeScript, JavaScript, and Java.

What topics does "The Singleton Pattern: The Full Code" cover?

This article covers: singleton pattern full example, singleton pattern project structure, singleton pattern c++, meyers singleton, gang of four design patterns, design patterns explained.

Singleton Pattern: Complete Multi-File Code Example

The last two posts built the singleton pattern piece by piece. This post is the reference: the whole project, as real files in real folders, using the idiomatic, thread-safe version of each language, a function-local static in C++ and the initialization-on-demand holder in Java.

main.cpp

#include <iostream>
#include <thread>
#include <vector>
#include "connectionpool/ConnectionPool.h"

int main() {
    const int threadCount = 8;
    std::vector<std::thread> threads;
    std::vector<ConnectionPool*> results(threadCount);

    for (int i = 0; i < threadCount; ++i) {
        threads.emplace_back([&results, i]() {
            results[i] = &ConnectionPool::getInstance();
        });
    }

    for (auto& t : threads) t.join();

    for (ConnectionPool* pool : results) {
        std::cout << pool << "\n";
    }

    return 0;
}

Run this yourself: This exact file layout lives in the code-practice repo. Clone it, cd into whichever language folder, and build it the same way as the other labs in this series.