Sorting a Map based on Values

[Vaibhav G Garg]

Hi,

I have a Map of Language Code (as Key) and Lanuage (as Value). I have to sort the map based on the values in the map.

But, in addition, there is a requirement that certain languages such as EN=>English, SP=>Spanish will always be on the top of the map. So, please suggest a suitable approach to achieve this.

Thanks.

[Joanne Neal]

First of all you have to be using a Map implementation that supports sorting (suitable Maps will be those that implement the SortedMap interface) and then you need to write a suitable Comparator, an instance of which you pass to your Map's constructor.
Remember that the Comparator operates on the Keys in the Map, so you will have to fetch the appropriate Values when implementing the compare method.

[Campbell Ritchie]

You also need to apply criteria to the keys for them to be sorted with.

[Winston Gutkowski]

Vaibhav G Garg wrote:I have a Map of Language Code (as Key) and Lanuage (as Value). I have to sort the map based on the values in the map.

This might sound a bit nitpicky, but you don't sort a Map; it has an intrinsic order, which is quite different.

Sorting is an action. I can take a "random" List of items and sort it any way I like, but a Map's order is determined at the time it's created and cannot be changed after that.

So what you actually want to know is how to order a Map the way you want and, as Joanne said, a custom Comparator (java.util.Comparator) sounds like what you want.

HIH

Winston