Class StateMap<TKey, TState>

Namespace

SodaFlow.Collections

Assembly

SodaFlow.Core.Collections.dll

A view of the mutable part of each item that other code cannot change. The key comes from the immutable part.

[PublicAPI]
public abstract class StateMap<TKey, TState> where TKey : notnull

Type Parameters

TKey

The type of the keys.

TState

The type of the mutable part of an item.

Inheritance

object

StateMap<TKey, TState>

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Extension Methods

CollectionExtensionMethods.Lookup<TKey, TState>(StateMap<TKey, TState>, TKey)

MaybeExtensionMethods.ToMaybe<T>(T?)

UnitExtensionMethods.Ignore<T>(T)

UnitExtensionMethods.Upcast<T>(T)

Remarks

This type selects the storage strategy. Each implementation must obey this contract:

A value returned by an instance never changes for the lifetime of that instance.

In a transaction, SodaFlow reads the value of a cell from before that transaction. When a snapshot from before points to storage that other code changed, those reads give a future value and no message. Thus, an implementation that changes its storage in position must give a version to that storage and must answer an older instance from a record. It must not answer with the live map.

A lookup is a TryGet and not an optional value, because this assembly does not reference SodaFlow.Functional. Each language wrapper adds a Lookup above this type, and that Lookup answers with the optional type of its language.

Properties

Count

The number of items in this version of the map.

Keys

The keys in this version of the map, in no particular order.

Pairs

Each key with its state, in no sequence. This is one read of the map and not one lookup for each key.

Methods

ContainsKey(TKey)

True when this version of the map has a key.

TryGetState(TKey, out TState?)

Returns the state for a key, when there is one.