Re: Snapshot of List [Was: Re: sync on local variable]

From:
=?ISO-8859-1?Q?Arne_Vajh=F8j?= <arne@vajhoej.dk>
Newsgroups:
comp.lang.java.programmer
Date:
Fri, 26 Mar 2010 20:59:50 -0400
Message-ID:
<4bad5880$0$272$14726298@news.sunsite.dk>
On 26-03-2010 10:22, Eric Sosman wrote:

On 3/25/2010 3:28 PM, Daniel Pitts wrote:

On 3/25/2010 11:06 AM, Eric Sosman wrote:

 >> [... about iterating over a changing List ...]

to keep the
iteration self-consistent you might want to do something like
lock ALL_ROWS, grab a snapshot with toArray(), unlock, and run
the iteration on the (private, stable) snapshot.

 >

I agree except, don't use toArray, use new ArrayList<Row>();


Not confrontational, just curious: Why prefer a new ArrayList
to an array? To me, it appears that an ArrayList is just an array
wrapped up in extra machinery, and I can't see that the machinery
adds any value for this usage. So, why pay the extra freight?
What am I missing?


As a general rule:

know that more functionality than array will be needed in the future =>
pick ArrayList

know that more functionality than array will NOT be needed in the future
=> pick array

don't know if more functionality than array will be needed in the future
=> pick ArrayList

My assumption would be that in the real world that would be 10%-10%-80%.

Obviously you can argue that this seems fell in category #2.

Arne

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