org.elasticsearch.search.suggest.completion.CompletionSuggester Maven / Gradle / Ivy
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* the Apache License, Version 2.0 (the "License"); you may
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* http://www.apache.org/licenses/LICENSE-2.0
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package org.elasticsearch.search.suggest.completion;
import org.apache.lucene.index.LeafReaderContext;
import org.apache.lucene.search.BulkScorer;
import org.apache.lucene.search.CollectionTerminatedException;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.Weight;
import org.apache.lucene.search.suggest.Lookup;
import org.apache.lucene.search.suggest.document.CompletionQuery;
import org.apache.lucene.search.suggest.document.TopSuggestDocs;
import org.apache.lucene.search.suggest.document.TopSuggestDocsCollector;
import org.apache.lucene.util.CharsRefBuilder;
import org.apache.lucene.util.PriorityQueue;
import org.elasticsearch.common.text.Text;
import org.elasticsearch.index.mapper.CompletionFieldMapper;
import org.elasticsearch.search.suggest.Suggest;
import org.elasticsearch.search.suggest.Suggester;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
public class CompletionSuggester extends Suggester {
public static final CompletionSuggester INSTANCE = new CompletionSuggester();
private CompletionSuggester() {}
@Override
protected Suggest.Suggestion> innerExecute(String name,
final CompletionSuggestionContext suggestionContext, final IndexSearcher searcher, CharsRefBuilder spare) throws IOException {
if (suggestionContext.getFieldType() != null) {
final CompletionFieldMapper.CompletionFieldType fieldType = suggestionContext.getFieldType();
CompletionSuggestion completionSuggestion = new CompletionSuggestion(name, suggestionContext.getSize());
spare.copyUTF8Bytes(suggestionContext.getText());
CompletionSuggestion.Entry completionSuggestEntry = new CompletionSuggestion.Entry(
new Text(spare.toString()), 0, spare.length());
completionSuggestion.addTerm(completionSuggestEntry);
TopSuggestDocsCollector collector = new TopDocumentsCollector(suggestionContext.getSize());
suggest(searcher, suggestionContext.toQuery(), collector);
int numResult = 0;
for (TopSuggestDocs.SuggestScoreDoc suggestScoreDoc : collector.get().scoreLookupDocs()) {
TopDocumentsCollector.SuggestDoc suggestDoc = (TopDocumentsCollector.SuggestDoc) suggestScoreDoc;
// collect contexts
Map> contexts = Collections.emptyMap();
if (fieldType.hasContextMappings() && suggestDoc.getContexts().isEmpty() == false) {
contexts = fieldType.getContextMappings().getNamedContexts(suggestDoc.getContexts());
}
if (numResult++ < suggestionContext.getSize()) {
CompletionSuggestion.Entry.Option option = new CompletionSuggestion.Entry.Option(suggestDoc.doc,
new Text(suggestDoc.key.toString()), suggestDoc.score, contexts);
completionSuggestEntry.addOption(option);
} else {
break;
}
}
return completionSuggestion;
}
return null;
}
private static void suggest(IndexSearcher searcher, CompletionQuery query, TopSuggestDocsCollector collector) throws IOException {
query = (CompletionQuery) query.rewrite(searcher.getIndexReader());
Weight weight = query.createWeight(searcher, collector.needsScores(), 1f);
for (LeafReaderContext context : searcher.getIndexReader().leaves()) {
BulkScorer scorer = weight.bulkScorer(context);
if (scorer != null) {
try {
scorer.score(collector.getLeafCollector(context), context.reader().getLiveDocs());
} catch (CollectionTerminatedException e) {
// collection was terminated prematurely
// continue with the following leaf
}
}
}
}
// TODO: this should be refactored and moved to lucene
// see https://issues.apache.org/jira/browse/LUCENE-6880
private static final class TopDocumentsCollector extends TopSuggestDocsCollector {
/**
* Holds a list of suggest meta data for a doc
*/
private static final class SuggestDoc extends TopSuggestDocs.SuggestScoreDoc {
private List suggestScoreDocs;
SuggestDoc(int doc, CharSequence key, CharSequence context, float score) {
super(doc, key, context, score);
}
void add(CharSequence key, CharSequence context, float score) {
if (suggestScoreDocs == null) {
suggestScoreDocs = new ArrayList<>(1);
}
suggestScoreDocs.add(new TopSuggestDocs.SuggestScoreDoc(doc, key, context, score));
}
public List getKeys() {
if (suggestScoreDocs == null) {
return Collections.singletonList(key);
} else {
List keys = new ArrayList<>(suggestScoreDocs.size() + 1);
keys.add(key);
for (TopSuggestDocs.SuggestScoreDoc scoreDoc : suggestScoreDocs) {
keys.add(scoreDoc.key);
}
return keys;
}
}
public List getContexts() {
if (suggestScoreDocs == null) {
if (context != null) {
return Collections.singletonList(context);
} else {
return Collections.emptyList();
}
} else {
List contexts = new ArrayList<>(suggestScoreDocs.size() + 1);
contexts.add(context);
for (TopSuggestDocs.SuggestScoreDoc scoreDoc : suggestScoreDocs) {
contexts.add(scoreDoc.context);
}
return contexts;
}
}
}
private static final class SuggestDocPriorityQueue extends PriorityQueue {
SuggestDocPriorityQueue(int maxSize) {
super(maxSize);
}
@Override
protected boolean lessThan(SuggestDoc a, SuggestDoc b) {
if (a.score == b.score) {
int cmp = Lookup.CHARSEQUENCE_COMPARATOR.compare(a.key, b.key);
if (cmp == 0) {
// prefer smaller doc id, in case of a tie
return a.doc > b.doc;
} else {
return cmp > 0;
}
}
return a.score < b.score;
}
public SuggestDoc[] getResults() {
int size = size();
SuggestDoc[] res = new SuggestDoc[size];
for (int i = size - 1; i >= 0; i--) {
res[i] = pop();
}
return res;
}
}
private final int num;
private final SuggestDocPriorityQueue pq;
private final Map scoreDocMap;
// TODO: expose dup removal
TopDocumentsCollector(int num) {
super(1, false); // TODO hack, we don't use the underlying pq, so we allocate a size of 1
this.num = num;
this.scoreDocMap = new LinkedHashMap<>(num);
this.pq = new SuggestDocPriorityQueue(num);
}
@Override
public int getCountToCollect() {
// This is only needed because we initialize
// the base class with 1 instead of the actual num
return num;
}
@Override
protected void doSetNextReader(LeafReaderContext context) throws IOException {
super.doSetNextReader(context);
updateResults();
}
private void updateResults() {
for (SuggestDoc suggestDoc : scoreDocMap.values()) {
if (pq.insertWithOverflow(suggestDoc) == suggestDoc) {
break;
}
}
scoreDocMap.clear();
}
@Override
public void collect(int docID, CharSequence key, CharSequence context, float score) throws IOException {
if (scoreDocMap.containsKey(docID)) {
SuggestDoc suggestDoc = scoreDocMap.get(docID);
suggestDoc.add(key, context, score);
} else if (scoreDocMap.size() <= num) {
scoreDocMap.put(docID, new SuggestDoc(docBase + docID, key, context, score));
} else {
throw new CollectionTerminatedException();
}
}
@Override
public TopSuggestDocs get() throws IOException {
updateResults(); // to empty the last set of collected suggest docs
TopSuggestDocs.SuggestScoreDoc[] suggestScoreDocs = pq.getResults();
if (suggestScoreDocs.length > 0) {
return new TopSuggestDocs(suggestScoreDocs.length, suggestScoreDocs, suggestScoreDocs[0].score);
} else {
return TopSuggestDocs.EMPTY;
}
}
}
}
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