[
https://issues.apache.org/jira/browse/LUCENE-1652?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12712733#action_12712733
]
Shai Erera commented on LUCENE-1652:
------------------------------------
bq. If we did these, you could upgrade to 2.9, fix all deprecations, then
upgrade to 3.0, recompile just fine ...
I'm not sure about it. In 3.0, we'll make nextDoc() abstract (for sure, since
the default impl calls next()) and probably advance() also. So when you upgrade
to 2.9, you can switch to calling nextDoc() and advance(), but if you
implemented DISI, you won't be required to implement nextDoc() and/or
advance(), so when you upgrade to 3.0 your code won't compile.
When upgrading, I think we should assume (or even require) users reading
CHANGES. When they notice that DISI has changed and that they need to implement
two new methods, they should also notice the change in semantics of doc().
I take it that by "catastrophic" you mean that you're ok with people upgrading
to 3.0 and don't compile, since that will force them to read CHANGES or
javadocs and understand what they are now supposed to implement. Therefore if
document() documents the new semantics, it is ok for us to rely on that, and if
something fails, it's the user's problem.
bq. maybe we add DISI.document(), with the new semantics
If we add document() (note the longer method name, compared to doc()) we can
implement it following the new semantics and take advantage of that in 2.9
already (I think?). For example:
{code}
public abstract class DocIdSetIterator {
private int doc = -1;
public int document() { return doc; }
public int nextDoc() throws IOException {
if (next()) {
doc = doc();
} else {
doc = NO_MORE_DOCS;
}
return doc;
}
public int advance() throws IOException {
while ((doc = nextDoc()) < target) {}
return doc;
}
}
{code}
We also move to call document() internally. I think this should work?
If this indeed should work, where should I do it - in this issue (I need 1614
to be committed first) or in 1614?
> Enhancements to Scorers following the changes to DocIdSetIterator
> -----------------------------------------------------------------
>
> Key: LUCENE-1652
> URL: https://issues.apache.org/jira/browse/LUCENE-1652
> Project: Lucene - Java
> Issue Type: Improvement
> Components: Search
> Reporter: Shai Erera
> Fix For: 3.0
>
>
> In LUCENE-1614, we changed the semantics of DocIdSetIterator's methods to
> return a sentinel NO_MORE_DOCS (= Integer.MAX_VALUE) when the iterator has
> exhausted. Due to backward compatibility issues, we couldn't implement that
> semantics in doc(). Therefore this issue, which can be introduced in 3.0 only
> will:
> # Implement the new semantics in all extending classes, such that doc() will
> return NO_MORE_DOCS when the iterator has exhausted.
> # Change BooleanScorer to take advantage of that by removing sub.done from
> SubScorer and operate under the assumption that NO_MORE_DOCS is larger than
> any doc ID (Integer.MAX_VALUE).
> # Change ConjunctionScorer to operate under the same assumptions and remove
> 'more'.
> # Change ReqExclScorer to not rely on reqScorer in doc(), since the latter
> may be null.
> # Make more changes to ConjunctionScorer's init() and remove 'firstTime' to
> improve the performance of nextDoc(), score(), advance().
> # Add start()/finish() to DISI?
> A snippet from LUCENE-1614 regarding the change in BooleanScorer
> {code}
> int doc = sub.done ? -1 : scorer.doc();
> while (!sub.done && doc < end) {
> sub.collector.collect(doc);
> doc = scorer.nextDoc();
> sub.done = doc < 0;
> }
> {code}
> To this:
> {code}
> int doc = scorer.doc();
> while (doc < end) {
> sub.collector.collect(doc);
> doc = scorer.nextDoc();
> }
> {code}
> And in ConjunctionScorer, change this:
> {code}
> while (more && (firstScorer=scorers[first]).doc() <
> (lastDoc=lastScorer.doc())) {
> more = firstScorer.advance(lastDoc) >= 0;
> lastScorer = firstScorer;
> first = (first == (scorers.length-1)) ? 0 : first+1;
> }
> return more;
> {code}
> To this:
> {code}
> while ((firstScorer=scorers[first]).doc() < (lastDoc=lastScorer.doc())) {
> firstScorer.advance(lastDoc);
> lastScorer = firstScorer;
> first = (first == (scorers.length-1)) ? 0 : first+1;
> }
> return lastDoc != DOC_SENTINEL;
> {code}
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
