protected IQueryable <GeoDataEntry> Search(string searchTerm, BoundingBox boundingBox, int maxResults)
{
lock (Entries)
{
//always want to query at least DataProviderMinResults # of entries so that
//Ranking logic is (most) accurately applied
maxResults = Math.Max(maxResults, DataProviderMinResults);
//remove entry if it already exists and is expired
var newKey = new ServiceCacheKey(StringComparer, boundingBox, searchTerm, maxResults);
ServiceCacheKey existingKey = Entries.ContainsKey(newKey) ? Entries.Keys.Single(k => k.Equals(newKey)) : null;
if (existingKey != null && IsFlushable(existingKey))
{
Entries.Remove(existingKey);
existingKey = null;
}
//if this set of args hasn't been queried before, or
//if it has but for a lower number of maxResults, refresh cache for this key
if (existingKey == null || existingKey.MaxResults < maxResults)
{
if (boundingBox != null)
{
Entries[newKey] = DataProvider.SearchNear(searchTerm, boundingBox, maxResults);
}
else
{
Entries[newKey] = DataProvider.Search(searchTerm.Trim(), maxResults);
}
}
return(Entries[newKey]);
}
}
private void AddCacheKey(ILEmitResolverBuilderContext argument, ServiceCacheKey key)
{
// new ServiceCacheKey(typeof(key.Type), key.Slot)
argument.Generator.Emit(OpCodes.Ldtoken, key.Type);
argument.Generator.Emit(OpCodes.Call, GetTypeFromHandleMethod);
argument.Generator.Emit(OpCodes.Ldc_I4, key.Slot);
argument.Generator.Emit(OpCodes.Newobj, CacheKeyCtor);
}
/// <summary>
/// returns true if a cache entry has expired
/// </summary>
/// <returns></returns>
protected bool IsFlushable(ServiceCacheKey key)
{
return(DateTime.Now - key.CreatedTime > CacheDuration);
}
