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From: blmblm@myrealbox.com <blmblm.myrealbox@gmail.com>
Newsgroups: comp.lang.java.programmer
Subject: Re: StringBuilder Difficulties
Date: 30 Jun 2011 20:30:00 GMT
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In article <irln07dveti624e71v8viderf0hjtudue5@4ax.com>,
Gene Wirchenko  <genew@ocis.net> wrote:
> <blmblm.myrealbox@gmail.com> wrote:
> 
> >In article <c4tk07dv1pq7u8k32qd6b7o1brc2rj8r30@4ax.com>,
> >Gene Wirchenko  <genew@ocis.net> wrote:

[ snip ]

> >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%.

So okay, you probably *do* want to use StringBuilder, and having
that confirmed by experiment is good.  

[ snip ]

> >(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).

More useful information; thanks for the reply.

A general comment:  I'm inclined to agree with the people who are
saying that in general it seems like you're trying to write [name
of your favorite language] programs in Java, and in the long term
that seems less optimal than trying to grok the Java mindset.  
I think part of it may be struggling with the object-oriented
paradigm, but part of it may just be coming to terms with the fact
that Java is, as I think Patricia Shanahan said not long ago
(possibly in another thread), that Java is just plain verbose.

But I have some sympathy with the desire just to get something 
running:  I spent a number of hours a while back trying to teach
myself some Scheme and in the process trying make it conform to
my strongly-typed-languages-trained mindset, and I'd probably
have done better to get a good introductory book and try to grok
the no-types(?) mindset.  (Maybe I'll try again at some point.)

-- 
B. L. Massingill
ObDisclaimer:  I don't speak for my employers; they return the favor.