protected override Dictionary <T, string> GetDictionaryToCache(LookupDataByValue lookupDataByValue)
{
DataTable dataTable = _databaseFactory.Create(lookupDataByValue.DataSource)
.Execute($"SELECT * FROM {lookupDataByValue.TableName}");
string columnNameOfPrimaryKey = lookupDataByValue.ColumnNameOfPrimaryKey ?? dataTable.Columns[0].ColumnName;
string columnNameOfFieldName = lookupDataByValue.ColumnNameOfFieldName ?? dataTable.Columns[1].ColumnName;
return(dataTable.AsEnumerable()
.ToDictionary(dr => (T)dr[columnNameOfPrimaryKey], dr => dr[columnNameOfFieldName] == DBNull.Value ? null : dr[columnNameOfFieldName].ToString()));
}
protected override Dictionary <TValue, string> GetDictionaryToCache(LookupDataByValue lookupDataByValue)
{
string sql = $"SELECT * FROM {lookupDataByValue.TableName} (NOLOCK)";
DataTable dataTable = ExecuteSql(sql, lookupDataByValue.DataSource);
string columnNameOfPrimaryKey = lookupDataByValue.ColumnNameOfPrimaryKey ?? dataTable.Columns[0].ColumnName;
string columnNameOfField = lookupDataByValue.ColumnNameOfField ?? dataTable.Columns[1].ColumnName;
return(dataTable.AsEnumerable()
.ToDictionary(dr => (TValue)dr[columnNameOfPrimaryKey], dr => dr[columnNameOfField] == DBNull.Value ? null : dr[columnNameOfField].ToString()));
}
private T GetLookupValue(LookupDataByValue lookupDataByValue, string cacheKey)
{
Dictionary <T, string> lookupValues =
_cache.GetOrAdd(cacheKey, () => GetDictionaryToCache(lookupDataByValue), GetCacheTimeoutInHours(lookupDataByValue));
KeyValuePair <T, string> keyValuePair = lookupValues
.SingleOrDefault(kvp => String.Equals(kvp.Value, lookupDataByValue.Value, StringComparison.OrdinalIgnoreCase));
if (keyValuePair.Equals(default(KeyValuePair <int, string>)))
{
return(default(T));
}
return(keyValuePair.Key);
}
/// <summary>
/// This is the protected AutoMapper method called within a mapper class when using opt.ResolveUsing()
/// In this class, GetLookupValue() is called twice as a type of self-healing mechanism whereby if we can't find the value the first time, we'll clear the cache and try again
/// This is because it's possible for a new value to be inserted into a lookup table after this cache is loaded but before the cache timeout expires
/// If we don't find what we're looking for, we make a one-time assumption that the cache could be out of sync, so we refresh the cache and try one more time to get the expected value
/// </summary>
public override T Resolve(object source, object destination, LookupDataByValue sourceMember, T destMember, ResolutionContext context)
{
if (sourceMember == null || String.IsNullOrEmpty(sourceMember.Value))
{
return(default(T));
}
string cacheKey = GetCacheKey(sourceMember.TableName);
T result = GetLookupValue(sourceMember, cacheKey);
if (EqualityComparer <T> .Default.Equals(result, default(T)))
{
_cache.Remove(cacheKey);
result = GetLookupValue(sourceMember, cacheKey);
}
return(result);
}
/// <summary>
/// This is the protected AutoMapper method called within a mapper class when using opt.ResolveUsing()
/// In this class, GetLookupValue() is called twice as a type of self-healing mechanism whereby if we can't find the value the first time, we'll clear the cache and try again
/// This is because it's possible for a new value to be inserted into a lookup table after this cache is loaded but before the cache timeout expires
/// If we don't find what we're looking for, we make a one-time assumption that the cache could be out of sync, so we refresh the cache and try one more time to get the expected value
/// </summary>
public override TValue Resolve(object source, object destination, LookupDataByValue sourceMember, TValue destMember, ResolutionContext context)
{
if (sourceMember == null || string.IsNullOrEmpty(sourceMember.Value))
{
return(default);
protected abstract Dictionary <TValue, string> GetDictionaryToCache(LookupDataByValue lookupDataByValue);
/// <summary>
/// Exposing the AutoMapper trigger method allows clients to use this resolver outside of an AutoMapper as well
/// </summary>
public T Resolve(LookupDataByValue lookupDataByValue)
{
return(Resolve(null, null, lookupDataByValue, default(T), null));
}
