/// <summary>
/// Get or add a DataLoader instance for caching data fetching operations.
/// </summary>
/// <typeparam name="T">The type of data to be loaded</typeparam>
/// <param name="context">The <seealso cref="DataLoaderContext"/> to get or add a DataLoader to</param>
/// <param name="loaderKey">A unique key to identify the DataLoader instance</param>
/// <param name="fetchFunc">A delegate to fetch data asynchronously</param>
/// <returns>A new or existing DataLoader instance</returns>
public static IDataLoader <T> GetOrAddLoader <T>(this DataLoaderContext context, string loaderKey, Func <Task <T> > fetchFunc)
{
if (context == null)
{
throw new ArgumentNullException(nameof(context));
}
if (fetchFunc == null)
{
throw new ArgumentNullException(nameof(fetchFunc));
}
return(context.GetOrAdd(loaderKey, () => new SimpleDataLoader <T>(WrapNonCancellableFunc(fetchFunc))));
}
/// <summary>
/// Get or add a DataLoader instance for batching data fetching operations.
/// </summary>
/// <typeparam name="TKey">The type of key used to load data</typeparam>
/// <typeparam name="T">The type of data to be loaded</typeparam>
/// <param name="context">The <seealso cref="DataLoaderContext"/> to get or add a DataLoader to</param>
/// <param name="loaderKey">A unique key to identify the DataLoader instance</param>
/// <param name="fetchFunc">A cancellable delegate to fetch data for some keys asynchronously</param>
/// <param name="keyComparer">An <seealso cref="IEqualityComparer{T}"/> to compare keys.</param>
/// <param name="defaultValue">The value returned when no match is found in the dictionary, or default(T) if unspecified</param>
/// <param name="maxBatchSize">The maximum number of keys passed to the fetch delegate at a time</param>
/// <returns>A new or existing DataLoader instance</returns>
public static IDataLoader <TKey, T> GetOrAddBatchLoader <TKey, T>(this DataLoaderContext context, string loaderKey, Func <IEnumerable <TKey>, CancellationToken, Task <IDictionary <TKey, T> > > fetchFunc,
IEqualityComparer <TKey>?keyComparer = null, T defaultValue = default !, int maxBatchSize = int.MaxValue)
{
if (context == null)
{
throw new ArgumentNullException(nameof(context));
}
if (fetchFunc == null)
{
throw new ArgumentNullException(nameof(fetchFunc));
}
return(context.GetOrAdd(loaderKey, () => new BatchDataLoader <TKey, T>(fetchFunc, keyComparer, defaultValue, maxBatchSize)));
}
/// <summary>
/// Get or add a DataLoader instance for batching data fetching operations.
/// </summary>
/// <typeparam name="TKey">The type of key used to load data</typeparam>
/// <typeparam name="T">The type of data to be loaded</typeparam>
/// <param name="context">The <seealso cref="DataLoaderContext"/> to get or add a DataLoader to</param>
/// <param name="loaderKey">A unique key to identify the DataLoader instance</param>
/// <param name="fetchFunc">A delegate to fetch data for some keys asynchronously</param>
/// <param name="keyComparer">An <seealso cref="IEqualityComparer{T}"/> to compare keys.</param>
/// <param name="maxBatchSize">The maximum number of keys passed to the fetch delegate at a time</param>
/// <returns>A new or existing DataLoader instance</returns>
public static IDataLoader <TKey, IEnumerable <T> > GetOrAddCollectionBatchLoader <TKey, T>(this DataLoaderContext context, string loaderKey, Func <IEnumerable <TKey>, Task <ILookup <TKey, T> > > fetchFunc,
IEqualityComparer <TKey>?keyComparer = null, int maxBatchSize = int.MaxValue)
{
if (context == null)
{
throw new ArgumentNullException(nameof(context));
}
if (fetchFunc == null)
{
throw new ArgumentNullException(nameof(fetchFunc));
}
return(context.GetOrAdd(loaderKey, () => new CollectionBatchDataLoader <TKey, T>(WrapNonCancellableFunc(fetchFunc), keyComparer, maxBatchSize)));
}