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From: Yann Simon <yann.simon.fr@gmail.com>
To: "Shawn O. Pearce" <spearce@spearce.org>
Cc: Robin Rosenberg <robin.rosenberg.lists@dewire.com>,
	git <git@vger.kernel.org>
Subject: Re: [PATCH] FindBugs: don't use new String(String) in RefDatabase
Date: Mon, 13 Jul 2009 10:07:02 +0200	[thread overview]
Message-ID: <551f769b0907130107j51d32e4er54e125f9dc61dd80@mail.gmail.com> (raw)
In-Reply-To: <20090710153441.GF11191@spearce.org>

2009/7/10 Shawn O. Pearce <spearce@spearce.org>:
>  Yann Simon <yann.simon.fr@gmail.com> wrote:
>  >
>  > However, using the trick newString = new String(aString.substring(),
>  > i) does not work on all JVM.
>  > With an IBM JVM, the newString will still contain the original array of chars.
>  >
>  > Another solution that work on all JVM could be:
>  > newString = new String(aString.substring(i).toCharArray())
>  > Or
>  > newString = new String(aString.toCharArray(), i, aString.length() - i)
>  >
>  > I like the latter one.
>
>  I prefer this.  It should always do what we want, and at a lower
>  temporary memory footprint (one less copy of the name).  IIRC Robin
>  rejected it earlier because it wasn't obvious what we were doing. I
>  say hogwash, its clear as mud.
>
> +       private static String copy(final String src, final int off, final int end) {
> +               return new StringBuilder(end - off).append(src, off, end).toString();
> +       }
> +

This method is quite clear.
One line javadoc would make it even clearer... :p (and maybe make Robin happy)

And you're right: by using a StringBuilder, we need one less arraycopy.

After committing your change, we can remove the entry to silent FindBugs.
(commit 21c3d82824075cd1f140b3bcf252dfaffe0fc96c)

Yann

  reply	other threads:[~2009-07-13  8:13 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-03-19  9:15 [PATCH JGIT] Method invokes inefficient new String(String) constructor Yann Simon
2009-03-19 16:01 ` Shawn O. Pearce
2009-03-19 16:44   ` Yann Simon
2009-07-09  8:47   ` Yann Simon
2009-07-10 15:34     ` [PATCH] FindBugs: don't use new String(String) in RefDatabase Shawn O. Pearce
2009-07-13  8:07       ` Yann Simon [this message]
2009-07-13 14:53         ` [JGIT PATCH v2] " Shawn O. Pearce
2009-07-21 14:50           ` Robin Rosenberg
2009-07-21 15:03             ` Shawn O. Pearce
2009-07-21 19:47               ` Robin Rosenberg

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