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array vs vector in real time environment

 
trupti nigam
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hi,
I want to know which one is better in real time environment the arrays or the vectors.
I have to process large amount of data ,but before that i have to find out that all are arranged serially & then put it in oracle DB & give the acknowledgement to the module from where i am getting this data.
please suggest any link or any information on this matter is welcome.
thanks in advance,
trupti
 
Peter den Haan
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It doesn't matter. Given that the information has to go into a database, any performance difference between an array and a list structure is going to pale in comparison to the database access overhead.
A List probably makes development a bit easier. But don't use a Vector, by all means use an ArrayList (see this thread to find out why). And always work with it through the List interface, so you can substitute a LinkedList if you find out that it is a better match for the operations you perform.
- Peter
 
trupti nigam
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hi,
how is the behaviour of array in run time environment?
thanks,
trupti
 
Peter den Haan
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Can you be more specific? I'm not sure I understand the question. Or rather, it looks so broad that the only reasonable answer would be "read the JLS".
- Peter
[This message has been edited by Peter den Haan (edited November 09, 2001).]
 
trupti nigam
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Hi peter,
what i meant by use of array in real time environment is..
as i said in my previous question that i am going to get real time data from one of the module,& i need to store it some place before putting in Db & file.( i want to reduce the time for DB queries..as the amount of data is huge)
so i was reading lot of stuff regarding the same to make a decision what is the best fit for us, i.e. array,vector or array list. i am thinking about the array but still not convinced whether it is the best fit.
if the size of the elements that will be stored in array is fixed then i think i can go for array.
thanks,
trupti
 
Peter den Haan
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Run-of-the-mill J2SE Java is not best suited to real-time programming, but you probably know that already. If you do want to use it have a look at the -Xgcinc switch. You may also be interested in the Real Time Java Specification.
Back to your question. An array is fastest, full stop. Question is, do you need it? I don't know what form your data takes and how stringent your real-time requirements are.
Assuming it's basically a large amount of simple numerical data - say, from a bunch of A/D converters - then an array has a huge advantage over any collection type: it can store primitive types (int,...). If you'd want store integers in a Vector, you'd need to instantiate Integer wrapper objects for all of them. Ouch.
If on the other hand you have a moderate flow of complicated or large chunks of data then modeling them as objects could be a good idea. If so, an ArrayList could be considered as an alternative to an array.
Whatever you do you'll have to take care of presizing - resizing a list is a costly operation that you might not be able to afford.
- Peter
 
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