/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
using System;
namespace Lucene.Net.Search
{
/// A Scorer for queries with a required subscorer
/// and an excluding (prohibited) sub DocIdSetIterator.
///
/// This Scorer implements ,
/// and it uses the skipTo() on the given scorers.
///
class ReqExclScorer:Scorer
{
private Scorer reqScorer;
private DocIdSetIterator exclDisi;
private int doc = - 1;
/// Construct a ReqExclScorer.
/// The scorer that must match, except where
///
/// indicates exclusion.
///
public ReqExclScorer(Scorer reqScorer, DocIdSetIterator exclDisi):base(null)
{ // No similarity used.
this.reqScorer = reqScorer;
this.exclDisi = exclDisi;
}
public override int NextDoc()
{
if (reqScorer == null)
{
return doc;
}
doc = reqScorer.NextDoc();
if (doc == NO_MORE_DOCS)
{
reqScorer = null; // exhausted, nothing left
return doc;
}
if (exclDisi == null)
{
return doc;
}
return doc = ToNonExcluded();
}
/// Advance to non excluded doc.
///
On entry:
///
/// - reqScorer != null,
/// - exclScorer != null,
/// - reqScorer was advanced once via next() or skipTo()
/// and reqScorer.doc() may still be excluded.
///
/// Advances reqScorer a non excluded required doc, if any.
///
/// true iff there is a non excluded required doc.
///
private int ToNonExcluded()
{
int exclDoc = exclDisi.DocID();
int reqDoc = reqScorer.DocID(); // may be excluded
do
{
if (reqDoc < exclDoc)
{
return reqDoc; // reqScorer advanced to before exclScorer, ie. not excluded
}
else if (reqDoc > exclDoc)
{
exclDoc = exclDisi.Advance(reqDoc);
if (exclDoc == NO_MORE_DOCS)
{
exclDisi = null; // exhausted, no more exclusions
return reqDoc;
}
if (exclDoc > reqDoc)
{
return reqDoc; // not excluded
}
}
}
while ((reqDoc = reqScorer.NextDoc()) != NO_MORE_DOCS);
reqScorer = null; // exhausted, nothing left
return NO_MORE_DOCS;
}
public override int DocID()
{
return doc;
}
/// Returns the score of the current document matching the query.
/// Initially invalid, until is called the first time.
///
/// The score of the required scorer.
///
public override float Score()
{
return reqScorer.Score(); // reqScorer may be null when next() or skipTo() already return false
}
public override int Advance(int target)
{
if (reqScorer == null)
{
return doc = NO_MORE_DOCS;
}
if (exclDisi == null)
{
return doc = reqScorer.Advance(target);
}
if (reqScorer.Advance(target) == NO_MORE_DOCS)
{
reqScorer = null;
return doc = NO_MORE_DOCS;
}
return doc = ToNonExcluded();
}
}
}