Java – how to check whether a key in a map starts with a given string value

I am looking for a way, such as:

myMap.containsKeyStartingWith("abc"); // returns true if there's a key starting with "abc" e.g. "abcd"

or

MapUtils.containsKeyStartingWith(myMap,"abc"); // same

I wonder if anyone knows a simple way to do this

thank you

Solution

This can be done using the standard SortedMap:

Map<String,V> tailMap = myMap.tailMap(prefix);
boolean result = (!tailMap.isEmpty() && tailMap.firstKey().startsWith(prefix));

Unordered maps (such as HashMap) do not support prefix lookup in essence, so for those maps where you have to iterate all keys