/*
* 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;
using PriorityQueue = Lucene.Net.Util.PriorityQueue;
namespace Lucene.Net.Search
{
/// A {@link HitCollector} implementation that collects the top-scoring
/// documents, returning them as a {@link TopDocs}. This is used by {@link
/// IndexSearcher} to implement {@link TopDocs}-based search.
///
/// This may be extended, overriding the collect method to, e.g.,
/// conditionally invoke super()
in order to filter which
/// documents are collected.
///
///
/// Please use {@link TopScoreDocCollector}
/// instead, which has better performance.
///
///
[Obsolete("Please use TopScoreDocCollector instead, which has better performance.")]
public class TopDocCollector:HitCollector
{
private ScoreDoc reusableSD;
/// The total number of hits the collector encountered.
protected internal int totalHits;
/// The priority queue which holds the top-scoring documents.
protected internal PriorityQueue hq;
/// Construct to collect a given number of hits.
/// the maximum number of hits to collect
///
public TopDocCollector(int numHits):this(new HitQueue(numHits, false))
{
}
/// use TopDocCollector(hq) instead. numHits is not used by this
/// constructor. It will be removed in a future release.
///
[Obsolete("use TopDocCollector(hq) instead. numHits is not used by this constructor. It will be removed in a future release.")]
internal TopDocCollector(int numHits, PriorityQueue hq)
{
this.hq = hq;
}
/// Constructor to collect the top-scoring documents by using the given PQ.
/// the PQ to use by this instance.
///
protected internal TopDocCollector(PriorityQueue hq)
{
this.hq = hq;
}
// javadoc inherited
public override void Collect(int doc, float score)
{
if (score > 0.0f)
{
totalHits++;
if (reusableSD == null)
{
reusableSD = new ScoreDoc(doc, score);
}
else if (score >= reusableSD.score)
{
// reusableSD holds the last "rejected" entry, so, if
// this new score is not better than that, there's no
// need to try inserting it
reusableSD.doc = doc;
reusableSD.score = score;
}
else
{
return ;
}
reusableSD = (ScoreDoc) hq.InsertWithOverflow(reusableSD);
}
}
/// The total number of documents that matched this query.
public virtual int GetTotalHits()
{
return totalHits;
}
/// The top-scoring hits.
public virtual TopDocs TopDocs()
{
ScoreDoc[] scoreDocs = new ScoreDoc[hq.Size()];
for (int i = hq.Size() - 1; i >= 0; i--)
// put docs in array
scoreDocs[i] = (ScoreDoc) hq.Pop();
float maxScore = (totalHits == 0)?System.Single.NegativeInfinity:scoreDocs[0].score;
return new TopDocs(totalHits, scoreDocs, maxScore);
}
}
}