无法初始化ArrayListMultimap;由于嵌套？

Question

private ArrayListMultimap<Integer, ArrayList<ArrayList<Point2d>>> detectedAgentPositions; 

上面的代码不会给我任何错误，即一切都整齐地写入和导入etcetera。但是，当我尝试初始化detectedAgentPositions像这样：

private ArrayListMultimap<Integer, ArrayList<ArrayList<Point2d>>> detectedAgentPositions 
     = new ArrayListMultimap<Integer, ArrayList<ArrayList<Point2d>>>(); 

我得到以下错误：

no suitable constructor found for ArrayListMultimap(no arguments) constructor ArrayListMultimap.ArrayListMultimap(int,int) is not applicable (actual and formal argument lists differ in length) constructor ArrayListMultimap.ArrayListMultimap(Multimap< ? extends Integer,? extends ArrayList>>) is not applicable (actual and formal argument lists differ in length)

有什么问题吗？

Answer 1

如果您ArrayListMultimap类是谷歌共同，它不只是因为构造函数是私人这样，你不能叫new ArrayListMultimap<Integer, ArrayList<ArrayList<Point2d>>>()直接简单地调用ArrayListMultimap.create()而不是为接下来的工作：

private ArrayListMultimap<Integer, ArrayList<ArrayList<Point2d>>> detectedAgentPositions 
    = ArrayListMultimap.create(); 

Answer 2

更好请使用以下代码：

Multimap<Integer, ArrayList<ArrayList<Point2d>>> detectedAgentPositions = ArrayListMultimap.create(); 

在这里阅读https://google.github.io/guava/releases/19.0/api/docs/com/google/common/collect/ArrayListMultimap.html