Re: Using Enumerated Types as Array Indexes

From:

Robert Klemme <shortcutter@googlemail.com>

Newsgroups:

comp.lang.java.programmer

Date:

Wed, 17 Aug 2011 16:04:09 +0200

Message-ID:

<9b2034Ff5mU1@mid.individual.net>

On 17.08.2011 14:29, David Lamb wrote:

On 16/08/2011 8:38 PM, Arne Vajh=F8j wrote:

On 8/16/2011 10:53 AM, KevinSimonson wrote:

Java is a pretty handy language in its own right. But in Ada one
could define arrays to be indexed by enumerated types. Can Java do
that? If not, why not?

Java is a simpler language than Ada. In Java array indexes are
int and you have byte/short/int/long types and that is it.

Sure -- but if Enums had been in the language from the beginning, then
it might have occurred to people that array indexes could be "any type
with a method 'int ordinal()'" (with the appropriate caveat about being=

in range 0..length-1)

Or we had an interface Countable { int ordinal(); } which Enum would
implement and which could be used for array indexing. Or... I don't
find it worthwhile to speculate about what could have happened if
something else happened.

And please also notice that there is still EnumMap as Patricia pointed
out - type safe, efficient and all. Just because Ada does it this way
doesn't mean that it's the best way or that other languages must follow
suit.

Kind regards

robert

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