如何为参数列表和/或返回类型中的“任何映射条目”值创建通用方法签名？

Question

In the code that I'm currently refactoring, there exists a similar operation on a bunch of Maps . All Maps are of the following type:

Map<<SomeType>,Double> myMap; 

They undergo the same transformation and are converted to:

TreeMap<Integer, <SomeType>> transformedMap;

I wanted to know if it's possible to create a generic method that looks something like this:

public TreeMap<Integer, <T>> transformMap(Map<<T>,Double> myMap){...}

What's the way to accomplish this? SomeType could be any kind of object/collection. I could replace <T> with Object but I wanted to know if there is a better solution. The above method signature, obviously doesn't work :)

SomeTypes are created by the system and operated upon in the code. I can't make any changes to their source.

Answer 1

You are close to a generic method solution. Define your generic type parameter with <T> , then use it without its own <> in the return type and parameter type.

public <T> TreeMap<Integer, T> transformMap(Map<T, Double> myMap) {...}