Question

I want to use MultiKeyMap from Apache Collection, because I need a HashMap with two keys and a value.
To put elements I do this:

private MultiKeyMap multiKey = new MultiKeyMap();
multiKey.put("key1.1", "key2.1", "value1");

And for get element I do this:

String s = multiKey.get("key1.1");

But the String s cames null… If I pass the two keys, like that:

String s = multiKey.get("key1.1", "key2.1");

The String s cames with values value1…

How can I extend the MultiKeyMap to get the right value when I pass only one of the two keys?

Answer 1

If you need only one key to get a value you have a plain old HashMap.

private Map<String, String> map = new HashMap<>();

map.put("key1.1", "value1");
map.put("key2.1", "value1");

And for get element you can do this:

String s = map.get("key1.1"); // s == "value1"

MultiKeyMap is required when both keys must be provided.