Groups > comp.lang.java.programmer > #2613

Re: Refactoring discovery

Path	csiph.com!x330-a1.tempe.blueboxinc.net!usenet.pasdenom.info!news.dougwise.org!news-transit.tcx.org.uk!eternal-september.org!feeder.eternal-september.org!.POSTED!not-for-mail
From	Joshua Cranmer <Pidgeot18@verizon.invalid>
Newsgroups	comp.lang.java.programmer
Subject	Re: Refactoring discovery
Date	Wed, 30 Mar 2011 17:31:53 -0400
Organization	A noiseless patient Spider
Lines	28
Message-ID	<in07ga$g5q$1@dont-email.me> (permalink)
References	<kbgoo6dfrkh58r3ogel9nb6rekrs258it2@4ax.com> <imi0cq$ah4$1@dont-email.me> <imjjus$2cj$1@lust.ihug.co.nz> <e7Mkp.1468$0s5.314@newsfe17.iad>
Mime-Version	1.0
Content-Type	text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding	7bit
Injection-Date	Wed, 30 Mar 2011 21:31:54 +0000 (UTC)
Injection-Info	mx02.eternal-september.org; posting-host="LtjcJP1H6uHOtkcPMh0bUA"; logging-data="16570"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1+tBMsDxBTlbN7IxA/Yra4wRJ8Zre/kWpI="
User-Agent	Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.16pre) Gecko/20110305 Lightning/1.0b3pre Thunderbird/3.1.10pre
In-Reply-To	<e7Mkp.1468$0s5.314@newsfe17.iad>
Cancel-Lock	sha1:9r3GOendUZMwzw+jhi7zC69H9y0=
Xref	x330-a1.tempe.blueboxinc.net comp.lang.java.programmer:2613

Show key headers only | View raw

On 03/30/2011 04:10 PM, David Lamb wrote:
> We already write "combined operations" in other contexts.
> if (x.hasKey(y)) then x.addPair(y,
> someVeryBigThingIDidn'tWantToSysnthesizeUnlessIHadTo)

Well, another way to implement this is:

public boolean hasKey(Y y) {
   LocPtr ptr = getWhereToInsert(y);
   this.cachedPtr = ptr;
   return ptr.valid();
}

public void addPair(Y y, Object obj) {
   LocPtr ptr;
   if (cachedPtr && cachedPtr.y == y)
     ptr = cachedPtr;
   else
     ptr = getWhereToInsert(y);
   ptr.insert(obj);
}

Which pretty much gets you the "benefit" of combining them into one 
single operation without needing to provide all of the back-level 
predicate code operations (set-if-present, set-if-not-present, etc.)
-- 
Beware of bugs in the above code; I have only proved it correct, not 
tried it. -- Donald E. Knuth

Back to comp.lang.java.programmer | Previous | Next — Previous in thread | Next in thread | Find similar

Thread

Re: Refactoring discovery David Lamb <dalamb@cs.queensu.ca> - 2011-03-30 16:10 -0400
  Re: Refactoring discovery David Lamb <dalamb@cs.queensu.ca> - 2011-03-30 16:25 -0400
  Re: Refactoring discovery Joshua Cranmer <Pidgeot18@verizon.invalid> - 2011-03-30 17:31 -0400
    Re: Refactoring discovery markspace <-@.> - 2011-03-30 15:52 -0700
    Re: Refactoring discovery Lew <noone@lewscanon.com> - 2011-03-30 23:58 -0400

csiph-web