aspose file tools*
The moose likes Beginning Java and the fly likes List in HashMap Big Moose Saloon
  Search | Java FAQ | Recent Topics | Flagged Topics | Hot Topics | Zero Replies
Register / Login
JavaRanch » Java Forums » Java » Beginning Java
Bookmark "List in HashMap" Watch "List in HashMap" New topic
Author

List in HashMap

AbhiRam Kalyan
Greenhorn

Joined: Oct 31, 2005
Posts: 25
Hello all,
I want to iterate through the list in HashMap and store the values as key and keys as values in a new hashmap.

Here is the HashMap with array list:
{secondval=[A3], firstval=[A2, A1], thirdval=[A4]}
Now i would like to store this in a new hashmap as {A1=firstval,A2=firstval,A3=thirdval,A4=fourthval}..

Please tell me what is the efficient way to iterate and store values in a new Hashmap.

Sasikanth
Rob Spoor
Sheriff

Joined: Oct 27, 2005
Posts: 19760
    
  20

Check out TreeMap and its constructors.


SCJP 1.4 - SCJP 6 - SCWCD 5 - OCEEJBD 6
How To Ask Questions How To Answer Questions
AbhiRam Kalyan
Greenhorn

Joined: Oct 31, 2005
Posts: 25
didnt get.could you show me an example?
Campbell Ritchie
Sheriff

Joined: Oct 13, 2005
Posts: 39828
    
  28
What didn't you understand about Maps or their implementations, particularly HashMap and TreeMap and how they sort or order their entries?
AbhiRam Kalyan
Greenhorn

Joined: Oct 31, 2005
Posts: 25
I understand about sort order and treemap. What i am trying to do is to create a new hashmap from
{secondval=[A3], firstval=[A2, A1], thirdval=[A4]}
which should represent as
Key Value
A1 firstval
A2 firstval
A3 secondval
A4 thirdval
Campbell Ritchie
Sheriff

Joined: Oct 13, 2005
Posts: 39828
    
  28
So each entry consists of a "V" for value and an array of "K" for keys which it should be applied to. And you want it to order with the "K"s sorted. I would repeat what Rob said: look at TreeMap and read its constructors; there are four overloaded constructors to read about. I presume you have some sort of Comparator already, or A1 and A2 implement Comparable.
AbhiRam Kalyan
Greenhorn

Joined: Oct 31, 2005
Posts: 25
Thanks for all your support.. i got the solution.
Campbell Ritchie
Sheriff

Joined: Oct 13, 2005
Posts: 39828
    
  28
Well done Please tell us what the solution was, so anybody having the same problem in the future can search for it.
 
It is sorta covered in the JavaRanch Style Guide.
 
subject: List in HashMap