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Posted to user@commons.apache.org by Stephen Colebourne <sc...@btopenworld.com> on 2006/03/02 19:11:11 UTC

Re: [Collections] Facing Design Issue

Think about what is most important, then next important and so on.

It seems that time is most important to you.
Then the grouping by id.
But its not clear what kind of qery you will make

There doesn't seem to be one collection that will fit.

Try looking at
- MultiHashMap to hold a list of objects against a single key
- MultiKeyMap to use multiple keys to lookup a single value
- MultiKey or an array to hold multiple objects as one object
- TreeMap to keep the keys sorted

Stephen

Rajat Sharma wrote:
> Hi,
> 
> I have the following strings....which are currently in an arraylist. 
> 
> Instance Date		Time	Var-1	Var-2
> 65793 	02/24/2006 00:00:00 	1 	1 
> 66049 	02/24/2006 00:00:00 	1 	1 
> 66305 	02/24/2006 00:00:00 	0 	0 
> 66561 	02/24/2006 00:00:00 	1 	3 
> 66817 	02/24/2006 00:00:00 	7 	4 
> 67073 	02/24/2006 00:00:00 	0 	0 
> 67329 	02/24/2006 00:00:00 	9 	16 
> 68353 	02/24/2006 00:00:00 	1 	1 
> 66817 	02/24/2006 00:02:30 	2 	2 
> 67073 	02/24/2006 00:02:30 	0 	0 
> 67329 	02/24/2006 00:02:30	 9 	9 
> 68353 	02/24/2006 00:02:30 	1	 1 
> 68609 	02/24/2006 00:02:30	 7 	7 
> 68865 	02/24/2006 00:02:30 	0 	0 
> 69121 	02/24/2006 00:02:30 	0 	0 
> 69377 	02/24/2006 00:02:30 	1 	1 
> 69633 	02/24/2006 00:02:30 	0	 0 
> 65793 	02/24/2006 00:03:00 	1 	0 
> 
> One thing unique in the above table is the time on a per instance basis. Var-1, and Var-2 are the attributes of the instance at any given time.
> 
> What I need is a very clean way to wrap these under collections framework, 
> 
> a) Such that all the instances having the same ID are in their own Collections 
> b) Most importantly, I could sort them with time. 
> 
> So all the unique instances help create separate tables each having the same ID, which can then be sorted on Date\Time such that sub-lists could be created which fall under the range of time given.
> 
> I am almost a beginner in collections and don't know if this is possible. Please note that, the above is not simly key-pair values but key-value-value....
> 
> Could someone help me.
> 
> Regards,
> Raj
> 
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