MicroElements.Collections.Sources 1.4.0

MicroElements.Collections.Sources

Summary

MicroElements source only package: Collection extensions: NotNull, Iterate, Materialize. Special collections: TwoLayerCache.

Extensions

NotNull

Returns not null (empty) enumeration if input is null.

string? GetFirstValue(IEnumerable<string>? optionalValues) =>
    optionalValues
        .NotNull()
        .FirstOrDefault();

Iterate

Iterates values and executes action for each value. It's like List.ForEach but works with lazy enumerations and does not forces additional allocations.

// Iterates values and outputs to console.
Enumerable
    .Range(1, 100_000)
    .Iterate(Console.WriteLine);

Materialize

Materializes source enumeration and allows to see intermediate results without changing execute chain. MaterializeDebug is the same as Materialize but works only in Debug mode and does not affect performance for Release builds.

Enumerable
    .Range(1, 10)
    .Materialize(values => { /*set breakpoint here*/ })
    .Iterate(Console.WriteLine);

Collections

TwoLayerCache

Represents ThreadSafe cache that holds only limited number of items. Can be used as drop in replacement for ConcurrentDictionary.

Use it when you need simple cache but with memory limit.

Notes:

• Cache organized in two layers: hot and cold.
• Items first added to cold cache.
• GetValue first checks hot cache. If value not found in hot cache than cold cache uses for search.
• If value exists in cold cache than item moves to hot cache.
• If hot cache exceeds item limit then hot cache became cold cache and new hot cache creates.