private string[] QueryOverMultipleWords(SuggestionQueryServerSide parameters, string queryText)
{
parameters.Popularity = false;
var individualTerms = queryText.Split(new[] { ' ', '\t', '\r', '\n' }, StringSplitOptions.RemoveEmptyEntries);
var result = new HashSet <string>();
var currentMaxSuggestions = parameters.MaxSuggestions;
foreach (var term in individualTerms)
{
if (currentMaxSuggestions <= 0)
{
break;
}
foreach (var suggestion in QueryOverSingleWord(parameters, term))
{
if (result.Add(suggestion) == false)
{
continue;
}
currentMaxSuggestions--;
if (currentMaxSuggestions <= 0)
{
break;
}
}
}
return(result.ToArray());
}
private SuggestionQueryServerSide GetSuggestionQuery(JsonOperationContext context, HttpMethod method)
{
if (method == HttpMethod.Get)
{
throw new NotImplementedException("RavenDB-8882");
}
var indexQueryJson = context.ReadForMemory(RequestBodyStream(), "suggestion/query");
// read from cache here
return(SuggestionQueryServerSide.Create(indexQueryJson));
}
private SuggestionQueryServerSide GetSuggestionQuery(JsonOperationContext context, HttpMethod method)
{
if (method == HttpMethod.Get)
{
//MoreLikeThisQueryServerSide.Create(HttpContext, GetPageSize(), context);
throw new NotImplementedException();
}
var indexQueryJson = context.ReadForMemory(RequestBodyStream(), "suggestion/query");
// read from cache here
return(SuggestionQueryServerSide.Create(indexQueryJson));
}
public string[] Suggestions(SuggestionQueryServerSide query, CancellationToken token)
{
var term = query.Term;
if (term.StartsWith("<<") && term.EndsWith(">>"))
{
return(QueryOverMultipleWords(query, term.Substring(2, term.Length - 4)));
}
if (term.StartsWith("(") && term.EndsWith(")"))
{
return(QueryOverMultipleWords(query, term.Substring(1, term.Length - 2)));
}
return(QueryOverSingleWord(query, term));
}
private string[] QueryOverSingleWord(SuggestionQueryServerSide parameters, string word)
{
// Perform devirtualization of the distance function when supported.
switch (parameters.Distance)
{
case StringDistanceTypes.JaroWinkler:
return(QueryOverSingleWord(parameters, word, new JaroWinklerDistance()));
case StringDistanceTypes.NGram:
return(QueryOverSingleWord(parameters, word, new NGramDistance()));
case StringDistanceTypes.Default:
case StringDistanceTypes.Levenshtein:
default:
return(QueryOverSingleWord(parameters, word, new LevenshteinDistance()));
}
}
public SuggestionQueryResultServerSide ExecuteSuggestionQuery(SuggestionQueryServerSide query, DocumentsOperationContext context, long?existingResultEtag, OperationCancelToken token)
{
if (query == null)
{
throw new ArgumentNullException(nameof(query));
}
// Check pre-requisites for the query to happen.
if (string.IsNullOrWhiteSpace(query.Term))
{
throw new InvalidOperationException("Suggestions queries require a term.");
}
if (string.IsNullOrWhiteSpace(query.Field))
{
throw new InvalidOperationException("Suggestions queries require a field.");
}
var sw = Stopwatch.StartNew();
// Check definition for the index.
var index = GetIndex(query.IndexName);
var indexDefinition = index.GetIndexDefinition();
if (indexDefinition == null)
{
throw new InvalidOperationException($"Could not find specified index '{this}'.");
}
if (indexDefinition.Fields.TryGetValue(query.Field, out IndexFieldOptions field) == false)
{
throw new InvalidOperationException($"Index '{this}' does not have a field '{query.Field}'.");
}
if (field.Suggestions == null)
{
throw new InvalidOperationException($"Index '{this}' does not have suggestions configured for field '{query.Field}'.");
}
if (field.Suggestions.Value == false)
{
throw new InvalidOperationException($"Index '{this}' have suggestions explicitly disabled for field '{query.Field}'.");
}
if (existingResultEtag.HasValue)
{
var etag = index.GetIndexEtag();
if (etag == existingResultEtag.Value)
{
return(SuggestionQueryResultServerSide.NotModifiedResult);
}
}
context.OpenReadTransaction();
var result = index.SuggestionsQuery(query, context, token);
result.DurationInMs = (int)sw.Elapsed.TotalMilliseconds;
return(result);
}
private string[] QueryOverSingleWord <TDistance>(SuggestionQueryServerSide parameters, string word, TDistance sd)
where TDistance : IStringDistance
{
float min = parameters.Accuracy.Value;
string field = parameters.Field;
int numSug = parameters.MaxSuggestions;
bool morePopular = parameters.Popularity;
int lengthWord = word.Length;
var ir = _searcher.IndexReader;
int freq = (ir != null && field != null) ? ir.DocFreq(new Term(FWord, word), _state) : 0;
int goalFreq = (morePopular && ir != null && field != null) ? freq : 0;
// if the word exists in the real index and we don't care for word frequency, return the word itself
if (!morePopular && freq > 0)
{
return(new[] { word });
}
var query = new BooleanQuery();
var alreadySeen = new HashSet <string>();
int ng = GetMin(lengthWord);
int max = ng + 1;
var table = GramsTable;
for (; ng <= max; ng++)
{
string[] grams = FormGrams(word, ng);
if (grams.Length == 0)
{
continue; // hmm
}
if (BoostStart > 0)
{
// should we boost prefixes?
Add(query, table[ng].Start, grams[0], BoostStart); // matches start of word
}
if (BoostEnd > 0)
{
// should we boost suffixes
Add(query, table[ng].End, grams[grams.Length - 1], BoostEnd); // matches end of word
}
for (int i = 0; i < grams.Length; i++)
{
Add(query, table[ng].Gram, grams[i]);
}
}
int maxHits = 10 * numSug;
// System.out.println("Q: " + query);
ScoreDoc[] hits = _searcher.Search(query, null, maxHits, _state).ScoreDocs;
// System.out.println("HITS: " + hits.length());
var queue = new SuggestWordQueue(numSug);
// go thru more than 'maxr' matches in case the distance filter triggers
int stop = Math.Min(hits.Length, maxHits);
var suggestedWord = new SuggestWord();
for (int i = 0; i < stop; i++)
{
suggestedWord.Term = _searcher.Doc(hits[i].Doc, _state).Get(FWord, _state); // get orig word
// don't suggest a word for itself, that would be silly
if (suggestedWord.Term.Equals(word, StringComparison.OrdinalIgnoreCase))
{
continue;
}
// edit distance
suggestedWord.Score = sd.GetDistance(word, suggestedWord.Term);
if (suggestedWord.Score < min)
{
continue;
}
if (ir != null && field != null)
{
// use the user index
suggestedWord.Freq = _searcher.DocFreq(new Term(FWord, suggestedWord.Term), _state); // freq in the index
// don't suggest a word that is not present in the field
if ((morePopular && goalFreq > suggestedWord.Freq) || suggestedWord.Freq < 1)
{
continue;
}
}
if (alreadySeen.Add(suggestedWord.Term) == false) // we already seen this word, no point returning it twice
{
continue;
}
queue.InsertWithOverflow(suggestedWord);
if (queue.Size() == numSug)
{
// if queue full, maintain the minScore score
min = queue.Top().Score;
}
suggestedWord = new SuggestWord();
}
int size = queue.Size();
if (size == 0)
{
return(EmptyArray);
}
// convert to array string
string[] list = new string[size];
for (int i = size - 1; i >= 0; i--)
{
list[i] = queue.Pop().Term;
}
return(list);
}
