func (s *Highlighter) BestFragmentsInField(dm *search.DocumentMatch, doc *document.Document, field string, num int) []string {
tlm := dm.Locations[field]
orderedTermLocations := highlight.OrderTermLocations(tlm)
scorer := NewFragmentScorer(tlm)
// score the fragments and put them into a priority queue ordered by score
fq := make(FragmentQueue, 0)
heap.Init(&fq)
for _, f := range doc.Fields {
if f.Name() == field {
_, ok := f.(*document.TextField)
if ok {
termLocationsSameArrayPosition := make(highlight.TermLocations, 0)
for _, otl := range orderedTermLocations {
if highlight.SameArrayPositions(f.ArrayPositions(), otl.ArrayPositions) {
termLocationsSameArrayPosition = append(termLocationsSameArrayPosition, otl)
}
}
fieldData := f.Value()
fragments := s.fragmenter.Fragment(fieldData, termLocationsSameArrayPosition)
for _, fragment := range fragments {
fragment.ArrayPositions = f.ArrayPositions()
scorer.Score(fragment)
heap.Push(&fq, fragment)
}
}
}
}
// now find the N best non-overlapping fragments
var bestFragments []*highlight.Fragment
if len(fq) > 0 {
candidate := heap.Pop(&fq)
OUTER:
for candidate != nil && len(bestFragments) < num {
// see if this overlaps with any of the best already identified
if len(bestFragments) > 0 {
for _, frag := range bestFragments {
if candidate.(*highlight.Fragment).Overlaps(frag) {
if len(fq) < 1 {
break OUTER
}
candidate = heap.Pop(&fq)
continue OUTER
}
}
bestFragments = append(bestFragments, candidate.(*highlight.Fragment))
} else {
bestFragments = append(bestFragments, candidate.(*highlight.Fragment))
}
if len(fq) < 1 {
break
}
candidate = heap.Pop(&fq)
}
}
// now that we have the best fragments, we can format them
orderedTermLocations.MergeOverlapping()
formattedFragments := make([]string, len(bestFragments))
for i, fragment := range bestFragments {
formattedFragments[i] = ""
if fragment.Start != 0 {
formattedFragments[i] += s.sep
}
formattedFragments[i] += s.formatter.Format(fragment, orderedTermLocations)
if fragment.End != len(fragment.Orig) {
formattedFragments[i] += s.sep
}
}
if dm.Fragments == nil {
dm.Fragments = make(search.FieldFragmentMap, 0)
}
if len(formattedFragments) > 0 {
dm.Fragments[field] = formattedFragments
}
return formattedFragments
}
