Singleton 模式 Java,c++实现

时间：2014-05-26 11:03:20 收藏：0 阅读：182

对于某些类，我们需要保证系统中只能有一个实例，这种类的设计用到singleton模式模式。

单线程的singleton模式是 straightforward的，下面给出Java和C++11的线程安全singleton实现

Java：

public class Singleton {
    private 
static Singleton instance = null;
    private 
static Object mutex = new 
Object();
     
    private 
Singleton() { }
     
    public 
static Singleton getInstance() {
        if(instance == null) {
            synchronized(mutex) {
                if(instance == null)
                    instance = new 
Singleton();
            }
        }
        return 
instance;
    }
}

C++:

static 
Singleton& get(){
  static 
Singleton instance;
  return 
instance;
}

C++11 remove the need for manual locking. Concurrent execution shall wait if a static local variable is already being initialized.

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