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sorting Arraylist of ArrayList


Joined: Dec 07, 2001
Posts: 4
We have a arraylist of arraylist which will fetch the value from the database and list the values in jsp page. The arraylist may contain various type of object and the size of the araylist of arraylist will be dynamic i.e will vary. Fro eg the arraylist may look like
[ [Suresh,20, 12/2/02, The test value],
[Xavier,26, 12/1/02, The test value with some other value],
[Varun,2, 1/2/02, The test value],
[Suba,24, 28/2/02, The test value],
The constraint is that that arraylist of arraylist must be sorted dynamically based on the datatypes ans well as the particular column.
for eg/ if i want to sort the given arraylist with respect to date value, The result of the sorted arraylist must contain the value based on the date and the order of the inner arraylist i.e the row value must not be changed.
Pls help me in solving the pbm.
Michael Ernest
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Joined: Oct 25, 2000
Posts: 7292

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Jim Yingst

Joined: Jan 30, 2000
Posts: 18671
You can find a discussion of a very similar problem here.
Chances are, you'll be better off replacing your ArrayList of ArrayLists with an ArrayList of CustomClass objects, where CustomClass is a class you have created to represent the data you're dealing with. In particular, to sort by the third column, date, it will be useful to have a data structure which understands that it is in fact a date, not some random String. Otherwise you will probably get an alphabetic sort, which would lead to problems like 1/1/02 coming before 2/1/01. If you parse these strings as Dates instead, you will be able to make meaningful comparisons.

"I'm not back." - Bill Harding, Twister
I agree. Here's the link:
subject: sorting Arraylist of ArrayList
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