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From: Jan Burse <janburse@fastmail.fm>
Newsgroups: comp.lang.java.programmer
Subject: Re: setSize ArrayList, when will it come?
Date: Tue, 09 Aug 2011 11:16:48 +0200
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Patricia Shanahan schrieb:
> On 8/8/2011 7:16 PM, Jan Burse wrote:
> ...
>> I actually do use setSize for a kind of sparse Vector.
>> Sparse in the sense that my Vector will have a couple
>> of holes represented by null value elements. Which
>> is eventually abuse of the term "sparse", but the use
>> case is there.
> ...
>
> If you only need small numbers of null elements, you could write a class
> extending ArrayList that has setSize(). All you would do is loop adding
> null elements or removing the tail elements until the ArrayList is the
> required size.
>
> Patricia

If only so many fields in ArrayList would not be private
I could do that. But since for example in JDK 1.6.0_26
none of the fields are protected, everything is private.

What you suggest is theoretically sound but practically
impossible. Look see:

public class ArrayList<E> extends ...
{
     private transient Object[] elementData;
     private int size;
     ...
}

And using reflection overriding this protection,
is kind of ugly and eventually less performant.

Bye