可清除的单例对象获取类

Posted 2022-08-20 math-and-it

public abstract class EnableCleanSingle<T>

    private volatile T object;

    private int updateCount;

    public T getObject() 
        if(object == null) 
            synchronized (this)
                if(object == null) 
                    createObject();
                    updateCount++;
                
            
        
　　　　　//这里在并发的时候，可能会返回null

        //解决方法:将整个方法都设为synchronized，但影响性能，这里就不改了
        return object;
    

    public void cleanObject()
        int old = updateCount;
        if(object != null) 
            synchronized (this) 
                if (updateCount == old) 
                    object = null;
                
            
        
    

    abstract public T createObject();