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https://issues.apache.org/jira/browse/OPENNLP-99?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12987150#action_12987150
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Jörn Kottmann commented on OPENNLP-99:
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One of the big issues we have currently with the EventStream is that it cannot
throw an exception when something goes wrong. Since it is a requirement to read
the data from disk, there is always a potential for failures. For me it seems
not possible to implement this nicely with an Iterator. In the opennlp tools
project we introduced the ObjectStream to circumvent these issues.
> EventStream should extend Iterator<Event>
> -----------------------------------------
>
> Key: OPENNLP-99
> URL: https://issues.apache.org/jira/browse/OPENNLP-99
> Project: OpenNLP
> Issue Type: New Feature
> Components: Maxent
> Affects Versions: maxent-3.0.0-sourceforge
> Reporter: Steven Bethard
>
> [As requested, brought over from Sourceforge.]
> Conceptually, EventStream is just an Iterator<Event>. You would get better
> interoperability with other Java libraries if EventStream were declared as
> such. If you didn't care about backwards compatibility, I'd say just get rid
> of EventStream entirely and use Iterator<Event> everywhere instead.
> If you care about backwards compatibility, you could at least declare
> AbstractEventStream as implementing Iterator<Event> - it declares all of
> hasNext(), next() and remove(). I believe that shouldn't break anything, and
> should make all the current EventStream implementations into Iterator<Event>s.
> Why do I want this? Because, when using OpenNLP maxent from Scala, if a
> RealValueFileEventStream were an Iterator<Event>, I could write:
> for (event <- stream) {
> ...
> }
> But since it's not, I instead have to wrap it in an Iterator:
> val events = new Iterator[Event] {
> def hasNext = stream.hasNext
> def next = stream.next
> }
> for (event <- events) {
> ...
> }
> Or write the while loop version:
> while (stream.hasNext) {
> val event = stream.next
> ...
> }
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