Re: Inheritance.

From:

"Mike Schilling" <mscottschilling@hotmail.com>

Newsgroups:

comp.lang.java.programmer

Date:

Tue, 02 May 2006 20:06:56 GMT

Message-ID:

<AZO5g.11065$Lm5.1387@newssvr12.news.prodigy.com>

"Chris Uppal" <chris.uppal@metagnostic.REMOVE-THIS.org> wrote in message
news:4457303a$0$654$bed64819@news.gradwell.net...

Mike Schilling wrote:

Just to nitpick, the Iterator could catch the IOException if it ever
occurs, and treat it the same as normal end of input. It could in that
case comply with its contract for hasNext() by always reading one line
ahead.

Wrong semantics, though, since returning false from hasNext() implies
that
it's successfully returned all the lines there are.

But does it ? Is the contract of fully generalized Iterator that
hasNext()
implies that it has successfully returned all the items, or that it has
returned all the items that it sucessfully can ?

The former, I think, just as I'd expect an I/O error reading a file to throw
IOException rather than return EOF. To put it another way, if I had a unti
test for this Iterator, and an intermittent disk failure resulted in an
unexpected exception, I'd understand why. If it resulted in a smaller
number of lines than expected, I'd be very confused.