Path: csiph.com!v102.xanadu-bbs.net!xanadu-bbs.net!feeder.erje.net!eu.feeder.erje.net!eternal-september.org!feeder.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail
From: markspace <markspace@nospam.nospam>
Newsgroups: comp.lang.java.programmer
Subject: Re: are lambdas a way to bring functional programming to java?
Date: Tue, 01 Jul 2014 19:58:26 -0700
Organization: A noiseless patient Spider
Lines: 36
Message-ID: <lovsgm$pdq$1@dont-email.me>
References: <ead6a498-272d-4ddd-b509-031bb858e882@googlegroups.com> <53ae08d5$0$304$14726298@news.sunsite.dk> <53ae0af4$0$302$14726298@news.sunsite.dk> <MPG.2e18d6e192455b131e@202.177.16.121> <53b36e09$0$293$14726298@news.sunsite.dk> <53b36f49$0$293$14726298@news.sunsite.dk>
Mime-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-15; format=flowed
Content-Transfer-Encoding: 8bit
Injection-Date: Wed, 2 Jul 2014 02:58:31 +0000 (UTC)
Injection-Info: mx05.eternal-september.org; posting-host="9358cda03e1e0dfd3c4b757daa608707"; logging-data="26042"; mail-complaints-to="abuse@eternal-september.org";	posting-account="U2FsdGVkX19VGC/DuTT0GNvTJ5wcz8HykjFvu+5ViYE="
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:24.0) Gecko/20100101 Thunderbird/24.6.0
In-Reply-To: <53b36f49$0$293$14726298@news.sunsite.dk>
Cancel-Lock: sha1:nvKP7BltXZsy/QgKciBsH/wDv9s=
Xref: csiph.com comp.lang.java.programmer:28902

On 7/1/2014 7:32 PM, Arne Vajhøj wrote:

>> On 6/28/2014 8:43 AM, Wanja Gayk wrote:
>>>
>>> static final Comparator<String> COMPARE_BY_LENGTH
>>>                = (s1,s2) -> s1.length() - s2.length()
>>>
>>> Collections.sort(lst, COMPARE_BY_LENGTH);

> BTW somewhat off-topic, I do not like the COMPARE_BY_LENGTH thingy.
>
> It is almost like:
>
> public static final int TWO = 2;

Just my two bits (heh):  This is a refactoring called Introduce 
Explaining Variable.

http://refactoring.com/catalog/extractVariable.html

(The bottom of that page explains that Martin Fowler has changed the 
name of his refactoring pattern to Extract Variable.)

The idea is to make the code easier to read by naming explicitly what is 
being done.  It isn't always obvious that length() - length() compares 
two values in ascending order ("natural order", I guess).  So by making 
it explicit you avoid adding a short comment like:

   // sort by natural order by lengths

It's "literate code" vs. "lots o' comments."  Depends which you like I 
suppose.  The refactored approach has some advantages.  Shorter line 
lengths is often one of them.  Easier to add more code, add debugging 
code or view the value in a debugger are others.