[SOLVED] LinkedHashMap

[mtyoung]

hi everyone,
i would like to know can we change the value of some "key"s in LinkedHashMap, and remain the order of "value" in LinkedHashMap?

[timkd127]

yes, you would have to make new LinkedHashMap. go through all the elements of the HashMap and put it into the new HashMap with a different key. Other than that i dont believe there is a way to change the key. Hope this helps.

[mtyoung]

thx for you suggestion

[OrangeDog]

Or write your own implementation that has a changeKey() method. It would involve a remove() and put() in the map, but not changing the list.

[mtyoung]

after remove and put, the order of linkedHashMap will change...

[OrangeDog]

No, you write your own version of LinkedHashMap. The simplest - though not most efficient - method it to encapsulate bot a Map and a List, then LinkedHashMap.put() calls both Map.put() and List.add(). LinkedHashMap.changeKey(old, new) would call Map.remove(old) and Map.put(new), but leave the List alone.

Alternatively, you can probably have a look at the source code for Sun's LinkedHashMap and add the functionality there.

[mtyoung]

thank you very much