/// <summary>
/// An instance of `MatchData` will be created for every term that matches a
/// document. However only one instance is required in an index result. This
/// method combines metadata from another instance of `MatchData` with this
/// object's metadata.
/// </summary>
/// <param name="otherMatchData">Another instance of match data to merge with this one.</param>
public void Combine(MatchData otherMatchData)
{
IEnumerable <string> terms = otherMatchData.Posting.Keys;
foreach (string term in terms)
{
IEnumerable <string> fields = otherMatchData.Posting[term].Keys;
if (!Posting.ContainsKey(term))
{
Posting.Add(term, new FieldMatches());
}
Dictionary <string, FieldMatchMetadata> thisTermEntry = Posting[term];
foreach (string field in fields)
{
IEnumerable <string> keys = otherMatchData.Posting[term][field].Keys;
if (!thisTermEntry.ContainsKey(field))
{
thisTermEntry.Add(field, new FieldMatchMetadata(capacity: otherMatchData.Posting[term][field].Keys.Count));
}
FieldMatchMetadata thisFieldEntry = thisTermEntry[field];
foreach (string key in keys)
{
IList <object?> otherData = otherMatchData.Posting[term][field][key];
if (!thisFieldEntry.ContainsKey(key))
{
thisFieldEntry.Add(key, new List <object?>(otherData));
}
else
{
thisFieldEntry[key] = thisFieldEntry[key].Concat(otherData).ToList();
}
}
}
}
}
/// <summary>Constructs a `MatchData`.</summary>
/// <param name="term">The term this match data is associated with.</param>
/// <param name="field">The field in which the term was found.</param>
/// <param name="metadata">The metadata recorded about this term in this field.</param>
public MatchData(
string term,
string field,
FieldMatchMetadata metadata)
{
Term = term;
Field = field;
// Cloning the metadata to prevent the original being mutated during match data combination.
// Metadata is kept in an array within the inverted index.
var clonedMetadata = new FieldMatchMetadata(capacity: metadata.Count);
foreach ((string key, IEnumerable <object?> value) in metadata)
{
clonedMetadata.Add(key, new List <object?>(value));
}
Posting = new InvertedIndexEntry
{
{
term,
new FieldMatches
{
{ field, clonedMetadata }
}
}
};
}
