[OPENNLP-99] EventStream should extend Iterator<Event>

• Type: New Feature
• Status: Closed
• Priority: Major
• Resolution: Won't Fix
• Affects Version/s: maxent-3.0.0-sourceforge
• Component/s: Machine Learning
• Assignee: Jörn Kottmann
• Reporter: Steven Bethard
• Created: 26/Jan/11 17:18
• Updated: 31/Jan/11 11:48
• Resolved: 31/Jan/11 11:48

Description

[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 ... }