IDEA geti 快捷键设置单例模式模板代码

private volatile static $CLASS_NAME$ INSTANCE; 
private $CLASS_NAME$ (){}

public static $CLASS_NAME$ getInstance(){
    if (INSTANCE == null) {
        synchronized ($CLASS_NAME$.class) {
            if (INSTANCE == null) {
                INSTANCE = new $CLASS_NAME$();
            }
        }
    }
    return INSTANCE;
}