private int GenerateBreakUpSuggestions(Term term, IndexReader ir,
int numberBreaks, int maxSuggestions, int useMinSuggestionFrequency,
SuggestWord[] prefix, JCG.PriorityQueue <SuggestWordArrayWrapper> suggestions,
int totalEvaluations, BreakSuggestionSortMethod sortMethod)
{
string termText = term.Text;
int termLength = termText.CodePointCount(0, termText.Length);
int useMinBreakWordLength = minBreakWordLength;
if (useMinBreakWordLength < 1)
{
useMinBreakWordLength = 1;
}
if (termLength < (useMinBreakWordLength * 2))
{
return(0);
}
int thisTimeEvaluations = 0;
for (int i = useMinBreakWordLength; i <= (termLength - useMinBreakWordLength); i++)
{
int end = termText.OffsetByCodePoints(0, i);
string leftText = termText.Substring(0, end);
string rightText = termText.Substring(end);
SuggestWord leftWord = GenerateSuggestWord(ir, term.Field, leftText);
if (leftWord.Freq >= useMinSuggestionFrequency)
{
SuggestWord rightWord = GenerateSuggestWord(ir, term.Field, rightText);
if (rightWord.Freq >= useMinSuggestionFrequency)
{
SuggestWordArrayWrapper suggestion = new SuggestWordArrayWrapper(NewSuggestion(prefix, leftWord, rightWord));
suggestions.Enqueue(suggestion);
if (suggestions.Count > maxSuggestions)
{
suggestions.Dequeue();
}
}
int newNumberBreaks = numberBreaks + 1;
if (newNumberBreaks <= maxChanges)
{
int evaluations = GenerateBreakUpSuggestions(new Term(term.Field, rightWord.String),
ir, newNumberBreaks, maxSuggestions,
useMinSuggestionFrequency, NewPrefix(prefix, leftWord),
suggestions, totalEvaluations, sortMethod);
totalEvaluations += evaluations;
}
}
thisTimeEvaluations++;
totalEvaluations++;
if (totalEvaluations >= maxEvaluations)
{
break;
}
}
return(thisTimeEvaluations);
}
// algorithm: treat sentence snippets as miniature documents
// we can intersect these with the postings lists via BreakIterator.preceding(offset),s
// score each sentence as norm(sentenceStartOffset) * sum(weight * tf(freq))
private Passage[] HighlightDoc(string field, BytesRef[] terms, int contentLength, BreakIterator bi, int doc,
TermsEnum termsEnum, DocsAndPositionsEnum[] postings, int n)
{
PassageScorer scorer = GetScorer(field);
if (scorer is null)
{
// LUCENENET: Changed from NullPointerException to InvalidOperationException (which isn't caught anywhere outside of tests)
throw IllegalStateException.Create("PassageScorer cannot be null");
}
JCG.PriorityQueue <OffsetsEnum> pq = new JCG.PriorityQueue <OffsetsEnum>();
float[] weights = new float[terms.Length];
// initialize postings
for (int i = 0; i < terms.Length; i++)
{
DocsAndPositionsEnum de = postings[i];
int pDoc;
if (de == EMPTY)
{
continue;
}
else if (de is null)
{
postings[i] = EMPTY; // initially
if (!termsEnum.SeekExact(terms[i]))
{
continue; // term not found
}
de = postings[i] = termsEnum.DocsAndPositions(null, null, DocsAndPositionsFlags.OFFSETS);
if (de is null)
{
// no positions available
throw new ArgumentException("field '" + field + "' was indexed without offsets, cannot highlight");
}
pDoc = de.Advance(doc);
}
else
{
pDoc = de.DocID;
if (pDoc < doc)
{
pDoc = de.Advance(doc);
}
}
if (doc == pDoc)
{
weights[i] = scorer.Weight(contentLength, de.Freq);
de.NextPosition();
pq.Add(new OffsetsEnum(de, i));
}
}
pq.Add(new OffsetsEnum(EMPTY, int.MaxValue)); // a sentinel for termination
JCG.PriorityQueue <Passage> passageQueue = new JCG.PriorityQueue <Passage>(n, Comparer <Passage> .Create((left, right) =>
{
if (left.score < right.score)
{
return(-1);
}
else if (left.score > right.score)
{
return(1);
}
else
{
return(left.startOffset - right.startOffset);
}
}));
Passage current = new Passage();
while (pq.TryDequeue(out OffsetsEnum off))
{
DocsAndPositionsEnum dp = off.dp;
int start = dp.StartOffset;
if (start == -1)
{
throw new ArgumentException("field '" + field + "' was indexed without offsets, cannot highlight");
}
int end = dp.EndOffset;
// LUCENE-5166: this hit would span the content limit... however more valid
// hits may exist (they are sorted by start). so we pretend like we never
// saw this term, it won't cause a passage to be added to passageQueue or anything.
if (Debugging.AssertsEnabled)
{
Debugging.Assert(EMPTY.StartOffset == int.MaxValue);
}
if (start < contentLength && end > contentLength)
{
continue;
}
if (start >= current.endOffset)
{
if (current.startOffset >= 0)
{
// finalize current
current.score *= scorer.Norm(current.startOffset);
// new sentence: first add 'current' to queue
if (passageQueue.Count == n && current.score < passageQueue.Peek().score)
{
current.Reset(); // can't compete, just reset it
}
else
{
passageQueue.Enqueue(current);
if (passageQueue.Count > n)
{
current = passageQueue.Dequeue();
current.Reset();
}
else
{
current = new Passage();
}
}
}
// if we exceed limit, we are done
if (start >= contentLength)
{
Passage[] passages = passageQueue.ToArray();
foreach (Passage p in passages)
{
p.Sort();
}
// sort in ascending order
ArrayUtil.TimSort(passages, Comparer <Passage> .Create((left, right) => left.startOffset - right.startOffset));
return(passages);
}
// advance breakiterator
if (Debugging.AssertsEnabled)
{
Debugging.Assert(BreakIterator.Done < 0);
}
current.startOffset = Math.Max(bi.Preceding(start + 1), 0);
current.endOffset = Math.Min(bi.Next(), contentLength);
}
int tf = 0;
while (true)
{
tf++;
BytesRef term = terms[off.id];
if (term is null)
{
// multitermquery match, pull from payload
term = off.dp.GetPayload();
if (Debugging.AssertsEnabled)
{
Debugging.Assert(term != null);
}
}
current.AddMatch(start, end, term);
if (off.pos == dp.Freq)
{
break; // removed from pq
}
else
{
off.pos++;
dp.NextPosition();
start = dp.StartOffset;
end = dp.EndOffset;
}
if (start >= current.endOffset || end > contentLength)
{
pq.Enqueue(off);
break;
}
}
current.score += weights[off.id] * scorer.Tf(tf, current.endOffset - current.startOffset);
}
// Dead code but compiler disagrees:
if (Debugging.AssertsEnabled)
{
Debugging.Assert(false);
}
return(null);
}
/// <summary>
/// <para>
/// Generate suggestions by combining one or more of the passed-in terms into
/// single words. The returned <see cref="CombineSuggestion"/> contains both a
/// <see cref="SuggestWord"/> and also an array detailing which passed-in terms were
/// involved in creating this combination. The scores returned are equal to the
/// number of word combinations needed, also one less than the length of the
/// array <see cref="CombineSuggestion.OriginalTermIndexes"/>. Generally, a
/// suggestion with a lower score is preferred over a higher score.
/// </para>
/// <para>
/// To prevent two adjacent terms from being combined (for instance, if one is
/// mandatory and the other is prohibited), separate the two terms with
/// <see cref="WordBreakSpellChecker.SEPARATOR_TERM"/>
/// </para>
/// <para>
/// When suggestMode equals <see cref="SuggestMode.SUGGEST_WHEN_NOT_IN_INDEX"/>, each
/// suggestion will include at least one term not in the index.
/// </para>
/// <para>
/// When suggestMode equals <see cref="SuggestMode.SUGGEST_MORE_POPULAR"/>, each
/// suggestion will have the same, or better frequency than the most-popular
/// included term.
/// </para>
/// </summary>
/// <returns> an array of words generated by combining original terms </returns>
/// <exception cref="IOException"> If there is a low-level I/O error. </exception>
public virtual CombineSuggestion[] SuggestWordCombinations(Term[] terms, int maxSuggestions,
IndexReader ir, SuggestMode suggestMode = SuggestMode.SUGGEST_WHEN_NOT_IN_INDEX)
{
if (maxSuggestions < 1)
{
return(Arrays.Empty <CombineSuggestion>());
}
int[] origFreqs = null;
if (suggestMode != SuggestMode.SUGGEST_ALWAYS)
{
origFreqs = new int[terms.Length];
for (int i = 0; i < terms.Length; i++)
{
origFreqs[i] = ir.DocFreq(terms[i]);
}
}
int queueInitialCapacity = maxSuggestions > 10 ? 10 : maxSuggestions;
IComparer <CombineSuggestionWrapper> queueComparer = new CombinationsThenFreqComparer();
JCG.PriorityQueue <CombineSuggestionWrapper> suggestions = new JCG.PriorityQueue <CombineSuggestionWrapper>(queueInitialCapacity, queueComparer);
int thisTimeEvaluations = 0;
for (int i = 0; i < terms.Length - 1; i++)
{
if (terms[i].Equals(SEPARATOR_TERM))
{
continue;
}
string leftTermText = terms[i].Text;
int leftTermLength = leftTermText.CodePointCount(0, leftTermText.Length);
if (leftTermLength > maxCombineWordLength)
{
continue;
}
int maxFreq = 0;
int minFreq = int.MaxValue;
if (origFreqs != null)
{
maxFreq = origFreqs[i];
minFreq = origFreqs[i];
}
string combinedTermText = leftTermText;
int combinedLength = leftTermLength;
for (int j = i + 1; j < terms.Length && j - i <= maxChanges; j++)
{
if (terms[j].Equals(SEPARATOR_TERM))
{
break;
}
string rightTermText = terms[j].Text;
int rightTermLength = rightTermText.CodePointCount(0, rightTermText.Length);
combinedTermText += rightTermText;
combinedLength += rightTermLength;
if (combinedLength > maxCombineWordLength)
{
break;
}
if (origFreqs != null)
{
maxFreq = Math.Max(maxFreq, origFreqs[j]);
minFreq = Math.Min(minFreq, origFreqs[j]);
}
Term combinedTerm = new Term(terms[0].Field, combinedTermText);
int combinedTermFreq = ir.DocFreq(combinedTerm);
if (suggestMode != SuggestMode.SUGGEST_MORE_POPULAR || combinedTermFreq >= maxFreq)
{
if (suggestMode != SuggestMode.SUGGEST_WHEN_NOT_IN_INDEX || minFreq == 0)
{
if (combinedTermFreq >= minSuggestionFrequency)
{
int[] origIndexes = new int[j - i + 1];
origIndexes[0] = i;
for (int k = 1; k < origIndexes.Length; k++)
{
origIndexes[k] = i + k;
}
SuggestWord word = new SuggestWord();
word.Freq = combinedTermFreq;
word.Score = origIndexes.Length - 1;
word.String = combinedTerm.Text;
CombineSuggestionWrapper suggestion = new CombineSuggestionWrapper(new CombineSuggestion(word, origIndexes), (origIndexes.Length - 1));
suggestions.Enqueue(suggestion);
if (suggestions.Count > maxSuggestions)
{
suggestions.TryDequeue(out CombineSuggestionWrapper _);
}
}
}
}
thisTimeEvaluations++;
if (thisTimeEvaluations == maxEvaluations)
{
break;
}
}
}
CombineSuggestion[] combineSuggestions = new CombineSuggestion[suggestions.Count];
for (int i = suggestions.Count - 1; i >= 0; i--)
{
combineSuggestions[i] = suggestions.Dequeue().CombineSuggestion;
}
return(combineSuggestions);
}
