public BlogReadService(
DataContext dataContext,
IKeywordProcessor keywordProcessor,
SearchSettings searchSettings
)
{
_dataContext = dataContext;
_keywordProcessor = keywordProcessor;
_searchSettings = searchSettings;
}
/// <summary>
/// <para>
/// Find items of type <see cref="T" /> which have matching keywords for the text passed
/// </para>
/// <para>Text is processed by the passed processor, which should be the same one that builds the keywords for the elements</para>
/// <para>
/// The search is ranked by Tf-idf <seealso cref="http://en.wikipedia.org/wiki/Tf%E2%80%93idf" />
/// </para>
/// </summary>
/// <typeparam name="T">Entity Type</typeparam>
/// <param name="source">
/// Queryable source of <see cref="T" />
/// </param>
/// <param name="text">Text to find</param>
/// <param name="keywordProcessor">Processes the text into keywords to search on</param>
/// <returns>Matching ranked elements</returns>
public static IQueryable <T> Match <T>(
this IQueryable <T> source,
string text,
IKeywordProcessor keywordProcessor)
where T : IndexedEntity
{
Contract.Requires(source != null);
Contract.Requires(!string.IsNullOrWhiteSpace(text));
Contract.Requires(keywordProcessor != null);
var keywords = keywordProcessor.Process(text, true);
return
(from e in source
let rank =
(
from ek in e.Keywords
where keywords.Any(k => ek.Keyword.Value.StartsWith(k))
select ek.Frequency / (decimal)ek.Keyword.Frequency
).Sum()
where rank > 0
orderby rank descending
select e);
}
public KeywordsBuilder(IKeywordProcessor processor)
{
_processor = processor;
_items = new HashSet <Func <T, IEnumerable <string> > >();
}
public KeywordsBuilderProvider(
IKeywordProcessor processor)
{
_processor = processor;
}
public PCF_Dictionary(IKeywordProcessor keywordProcessor)
{
_keywordProcessor = keywordProcessor;
_topLevelDictionary = CreateTopLevelDictionary();
_elementLevelDictionary = CreateElementLevelDictionary();
}
