private SelectableQuote[] SearchQuotesCached(IEnumerable <SelectableQuote> searchSource, SearchCacheKey key)
{
SelectableQuote[] returnValue = SearchQuotes(searchSource, key.SearchText, key.SearchTarget);
// add caching information
_oldSearchText = key.SearchText;
_oldSearchTarget = key.SearchTarget;
_searchResults.Add(key, returnValue);
return(returnValue);
}
public IList <SelectableQuote> FindQuotes(string searchText, SearchTargets searchTarget)
{
if (searchText == null)
{
throw new ArgumentNullException();
}
IList <SelectableQuote> returnValue;
if (searchText.Length > 0)
{
// only start caching if number of quotes exceeds the value of _cacheThreshold
if (_currentQuotePage.Count >= _cacheThreshold)
{
if (_searchResults == null)
{
WeakReference oldReference;
// try to get old search results belonging to the current QuotePage
if (OldSearchResults.TryGetValue(_currentQuotePage, out oldReference))
{
_searchResults = oldReference.Target as Dictionary <SearchCacheKey, SelectableQuote[]>;
// if not possible create it newly
if (_searchResults == null)
{
_searchResults = new Dictionary <SearchCacheKey, SelectableQuote[]>(_searchCacheKeyEqualityComparer);
OldSearchResults[_currentQuotePage] = new WeakReference(_searchResults);
}
}
else
{
_searchResults = new Dictionary <SearchCacheKey, SelectableQuote[]>(_searchCacheKeyEqualityComparer);
OldSearchResults.Add(_currentQuotePage, new WeakReference(_searchResults));
}
}
SelectableQuote[] result;
SearchCacheKey newKey = new SearchCacheKey(searchText, searchTarget);
// does a matching entry already exist?
if (_searchResults.TryGetValue(newKey, out result))
{
returnValue = result;
}
// is there an entry that can be reused for searching?
else if (searchText.Contains(_oldSearchText, _stringComparison) &&
((_oldSearchTarget == searchTarget &&
_searchResults.TryGetValue(new SearchCacheKey(_oldSearchText, _oldSearchTarget), out result)) ||
_searchResults.TryGetValue(new SearchCacheKey(_oldSearchText, SearchTargets.Everything), out result)))
{
returnValue = SearchQuotesCached(result, newKey);
}
// start search using the whole QuotePage
else
{
returnValue = SearchQuotesCached(_currentQuotePage, newKey);
}
}
// perform uncached search
else
{
returnValue = SearchQuotes(_currentQuotePage, searchText, searchTarget);
}
}
else
{
returnValue = (_dispatcher != null) ?
new DispatchingList <QuotePage, SelectableQuote>(_currentQuotePage, _dispatcher) as IList <SelectableQuote> :
_currentQuotePage as IList <SelectableQuote>;
}
return(returnValue);
}
