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From: Daniele Futtorovic <da.futt.news@laposte-dot-net.invalid>
Newsgroups: comp.lang.java.programmer
Subject: Re: "Program to an interface" - When to break a design pattern
Date: Tue, 10 May 2011 21:31:49 +0200
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On 10/05/2011 21:04, Jim Janney allegedly wrote:
> markspace<-@.>  writes:
>> As an example, here's a method in the Java API that returns an array --
>> something with NO constraints on data order -- and yet the docs for
>> the method say the order is guaranteed.
>>
>> <http://download.oracle.com/javase/6/docs/api/java/lang/Class.html#getEnumConstants%28%29>
>>
>> It's even a relatively recently added method too, not some historical
>> oddity.  So I agree it's legit to document, but not enforce by type,
>> ordering or other invariants on the objects a method returns.
>
> Not an analogous case.  When an array is ordered, the ordering is a
> property only of that particular instance, one that may cease to hold if
> the array is modified.  In contrast, every instance of LinkedHashMap
> always preserves the order of insertion, since this is a property that
> the class promises to maintain at all times.


> M*r*. Futtorovic's argument holds only if callers to getOrderedMap() never
> add new entries to it.

... while having an interest in its iteration order. But otherwise 
entirely correct and agreed.

-- 
DF.
An escaped convict once said to me:
"Alcatraz is the place to be"