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From: Gene Wirchenko <genew@ocis.net>
Newsgroups: comp.lang.java.programmer
Subject: Re: StringBuilder Difficulties
Date: Wed, 29 Jun 2011 18:55:14 -0700
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On 29 Jun 2011 20:17:37 GMT, blmblm@myrealbox.com
<blmblm.myrealbox@gmail.com> wrote:

>In article <c4tk07dv1pq7u8k32qd6b7o1brc2rj8r30@4ax.com>,
>Gene Wirchenko  <genew@ocis.net> wrote:

[snip]

>>      Am I missing something about StringBuilder, or is it really this
>> difficult to play with?  It would make a lot more sense to me if
>> StringBuilder worked more like String does.

[snip]

>up a string piece by piece.  You *could* write something like
>
>String a = "first";
>a += " second";
>a += " etc";
>
>and my *guess* is that this is not horribly inefficient if the
>number of concatenation operations is small.  (The conventional

     IOW, who cares if it is only a bit of inefficiency?  Agreed.

>wisdom, as I understand it, is that the Java runtime is pretty
>good at managing short-lived objects, so creating new objects is
>not invariably something to avoid, though as with anything else
>one shouldn't get carried away, maybe.  Again the experts may
>disagree.)
>
>But if there are a lot of concatenation operations it's said to be
>more efficient to use a StringBuilder, e.g.:
>
>StringBuilder sb = new StringBuilder();
>sb.append("first");
>sb.append(" second");
>sb.append(" etc");
>String a = sb.toString();

     It is.  My test code appends one character at a time. Switching
from String to StringBuilder cut the execution time by about 40%.

>The above is what I mostly use StringBuilder for; there are
>undoubtedly other things one can do with it as well, some of
>which may be useful to you (I haven't followed carefully all the
>threads you've started).

     I have managed to get to the point where I have found out what
you have posted here, and I agree with it, too.

>(I'm not optimistic that this commentary will be helpful, or
>even that it will be read [*], given that you didn't reply to
>my posts in the threads about passing method names to methods,
>but I guess I'll try again ....  <shrug> )
>
>[*] That's not actually meant as snark; not long ago I changed
>the e-mail address I use to post, to a GMail one, and I'm under
>the impression that some Usenet participants routinely filter out
>anything from a GMail address, so I worry just a bit ....

     Not me.  I killfile only the deserving (meaning those undeserving
of my time).

Sincerely,

Gene Wirchenko