package org.apache.lucene.search;
/**
* 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.
*/
import java.io.IOException;
import java.util.ResourceBundle;
/**
* Expert: Common scoring functionality for different types of queries.
*
* <p>
* A <code>Scorer</code> iterates over documents matching a
* query in increasing order of doc Id.
* </p>
* <p>
* Document scores are computed using a given <code>Similarity</code>
* implementation.
* </p>
*
* <p><b>NOTE</b>: The values Float.Nan,
* Float.NEGATIVE_INFINITY and Float.POSITIVE_INFINITY are
* not valid scores. Certain collectors (eg {@link
* TopScoreDocCollector}) will not properly collect hits
* with these scores.
*
* @see BooleanQuery#setAllowDocsOutOfOrder
*/
public abstract class Scorer extends DocIdSetIterator {
// TODO: may want to read number of sort fields straight out from schema.xml instead of setting property
public static int numSort = 5; // set default to be 5 sortable fields
// used to save bytes on current time minutes (2005/1/1)
protected static long SolbaseEpochTime = 18408960l;
// flag to use timeliness boosting factor.
protected static boolean enableTimelinessBoosting = false;
// field position for timeliness boosting
protected static int timelinessFieldPosition;
// boosting factor
protected static int boostingFactor = 10080; // 24 * 60 * 7 doing seven days boosting in minutes;
// timeliness boosting factor
protected static float boost = 5.0f;
static {
String numSortsStr = System.getProperty("lucene.sortablefield.num");
try {
ResourceBundle luceneBundle = ResourceBundle.getBundle("lucene");
if (numSortsStr == null && luceneBundle != null) {
try {
numSortsStr = luceneBundle.getString("sortablefield.num");
try {
numSort = Integer.parseInt(numSortsStr);
} catch (NumberFormatException e) {
// use default which is already set above
}
}catch (java.util.MissingResourceException e){
// use default
}
}
// initialize SolbaseEpochTime
try {
String solbaseEpochTimeStr = luceneBundle.getString("solbaseEpochTime");
try {
SolbaseEpochTime = Long.parseLong(solbaseEpochTimeStr);
} catch (NumberFormatException e) {
// use default
}
}catch (java.util.MissingResourceException e){
// use default
}
// init enableTimelinessBoosting flag
try {
String timelinessBoosting = luceneBundle.getString("timelinessBoosting");
if(timelinessBoosting.equals("true")) {
// make sure we have a field to get value for boosting comparison
try {
String fieldStr = luceneBundle.getString("timelinessBoosting.field.position");
timelinessFieldPosition = Integer.parseInt(fieldStr);
enableTimelinessBoosting = true;
} catch (NumberFormatException e) {
// can't get field postiion for timeliness boosting
// suppress timeliness boosting feature
} catch (java.util.MissingResourceException e) {
// use default
}
// init boosting val
try {
String boostStr = luceneBundle.getString("timelinessBoosting.boost");
boost = Float.parseFloat(boostStr);
} catch (NumberFormatException e) {
// use default 5.0f boost
} catch (java.util.MissingResourceException e) {
// use default
}
// init boosting factor
try {
String boostingFactorStr = luceneBundle.getString("timelinessBoosting.boostingFactor");
boostingFactor = Integer.parseInt(boostingFactorStr);
} catch (NumberFormatException e) {
// use default 7 days in seconds.
} catch (java.util.MissingResourceException e) {
// use default
}
}
} catch (java.util.MissingResourceException e){
// use default
}
} catch (java.util.MissingResourceException e){
// ignore if resouce is not here
}
}
private Similarity similarity;
/** Constructs a Scorer.
* @param similarity The <code>Similarity</code> implementation used by this scorer.
*/
protected Scorer(Similarity similarity) {
this.similarity = similarity;
}
/** Returns the Similarity implementation used by this scorer. */
public Similarity getSimilarity() {
return this.similarity;
}
/** Scores and collects all matching documents.
* @param hc The collector to which all matching documents are passed through
* {@link HitCollector#collect(int, float)}.
* <br>When this method is used the {@link #explain(int)} method should not be used.
* @deprecated use {@link #score(Collector)} instead.
*/
public void score(HitCollector hc) throws IOException {
score(new HitCollectorWrapper(hc));
}
/** Scores and collects all matching documents.
* @param collector The collector to which all matching documents are passed.
* <br>When this method is used the {@link #explain(int)} method should not be used.
*/
public void score(Collector collector) throws IOException {
collector.setScorer(this);
int doc;
while ((doc = nextDoc()) != NO_MORE_DOCS) {
collector.collect(doc, getSorts());
}
}
/** Expert: Collects matching documents in a range. Hook for optimization.
* Note that {@link #next()} must be called once before this method is called
* for the first time.
* @param hc The collector to which all matching documents are passed through
* {@link HitCollector#collect(int, float)}.
* @param max Do not score documents past this.
* @return true if more matching documents may remain.
* @deprecated use {@link #score(Collector, int, int)} instead.
*/
protected boolean score(HitCollector hc, int max) throws IOException {
return score(new HitCollectorWrapper(hc), max, docID());
}
/**
* Expert: Collects matching documents in a range. Hook for optimization.
* Note, <code>firstDocID</code> is added to ensure that {@link #nextDoc()}
* was called before this method.
*
* @param collector
* The collector to which all matching documents are passed.
* @param max
* Do not score documents past this.
* @param firstDocID
* The first document ID (ensures {@link #nextDoc()} is called before
* this method.
* @return true if more matching documents may remain.
*/
protected boolean score(Collector collector, int max, int firstDocID) throws IOException {
collector.setScorer(this);
int doc = firstDocID;
while (doc < max) {
collector.collect(doc, getSorts());
doc = nextDoc();
}
return doc != NO_MORE_DOCS;
}
/** Returns the score of the current document matching the query.
* Initially invalid, until {@link #next()} or {@link #skipTo(int)}
* is called the first time, or when called from within
* {@link Collector#collect}.
*/
public abstract float score() throws IOException;
/** Returns an explanation of the score for a document.
* <br>When this method is used, the {@link #next()}, {@link #skipTo(int)} and
* {@link #score(HitCollector)} methods should not be used.
* @param doc The document number for the explanation.
*
* @deprecated Please use {@link IndexSearcher#explain}
* or {@link Weight#explain} instead.
*/
public Explanation explain(int doc) throws IOException {
throw new UnsupportedOperationException();
}
}