Method FilterByIdentity

Namespace

SodaFlow.Collections

Assembly

SodaFlow.Collections.dll

FilterByIdentity<TKey, TIdentity, TState>(ReactiveCollection<TKey, TIdentity, TState>, Func<TIdentity, bool>)

Narrows the view with a predicate on the immutable part of each item, which is its identity. A state edit cannot change that part.

public static ReactiveCollection<TKey, TIdentity, TState> FilterByIdentity<TKey, TIdentity, TState>(this ReactiveCollection<TKey, TIdentity, TState> upstream, Func<TIdentity, bool> predicate) where TKey : notnull where TIdentity : notnull

Parameters

upstream ReactiveCollection<TKey, TIdentity, TState>

The collection or view to narrow.

predicate Func<TIdentity, bool>

Whether an item belongs in the view, given its identity.

Returns

ReactiveCollection<TKey, TIdentity, TState>

A view with the items that the predicate accepts.

Type Parameters

TKey

The type of the keys.

TIdentity

The type of the immutable part of an item.

TState

The type of the mutable part of an item.

Remarks

This gives the same members as Filter for the same answers, and it costs less to keep. A state edit cannot move a key into this filter or out of it, thus the stage does not test the predicate again and does not read the previous membership of the key. It sends the update on. This is not a statement that a reader must accept. The predicate receives the identity and not the state, thus it cannot read the state that it says it does not read.

FilterByIdentity<TKey, TIdentity, TState>(ReactiveCollection<TKey, TIdentity, TState>, Cell<Func<TIdentity, bool>>)

Narrows the view with a predicate on the identity of each item that can change. Each change to the predicate tests each item of the upstream again, and reports the keys that entered and left as inserts and removals, not as a reset.

public static ReactiveCollection<TKey, TIdentity, TState> FilterByIdentity<TKey, TIdentity, TState>(this ReactiveCollection<TKey, TIdentity, TState> upstream, Cell<Func<TIdentity, bool>> predicateCell) where TKey : notnull where TIdentity : notnull

Parameters

upstream ReactiveCollection<TKey, TIdentity, TState>

The collection or view to narrow.

predicateCell Cell<Func<TIdentity, bool>>

The predicate in force.

Returns

ReactiveCollection<TKey, TIdentity, TState>

A view with the items that the predicate accepts.

Type Parameters

TKey

The type of the keys.

TIdentity

The type of the immutable part of an item.

TState

The type of the mutable part of an item.

Remarks

See FilterByIdentity<TKey, TIdentity, TState>(ReactiveCollection<TKey, TIdentity, TState>, Func<TIdentity, bool>) . A state edit still does not test the predicate. When a change to the predicate moves more keys than a list of them is worth, this stage builds again, at a cost of O(m log m) in the size of the upstream, and reports a reset.

FilterByIdentity<TKey, TIdentity, TState, TCriteria>(ReactiveCollection<TKey, TIdentity, TState>, Cell<TCriteria>, Func<TCriteria, TIdentity, bool>)

Narrows the view with a predicate on the identity of each item from a different source, such as a search box or a toggle. Each change to the criteria tests each item of the upstream again, thus a criteria from a keystroke needs a Calm stage above this one.

public static ReactiveCollection<TKey, TIdentity, TState> FilterByIdentity<TKey, TIdentity, TState, TCriteria>(this ReactiveCollection<TKey, TIdentity, TState> upstream, Cell<TCriteria> criteriaCell, Func<TCriteria, TIdentity, bool> predicate) where TKey : notnull where TIdentity : notnull

Parameters

upstream ReactiveCollection<TKey, TIdentity, TState>

The collection or view to narrow.

criteriaCell Cell<TCriteria>

The criteria in force.

predicate Func<TCriteria, TIdentity, bool>

Whether an item belongs in the view, given the criteria and its identity.

Returns

ReactiveCollection<TKey, TIdentity, TState>

A view with the items that the predicate accepts.

Type Parameters

TKey

The type of the keys.

TIdentity

The type of the immutable part of an item.

TState

The type of the mutable part of an item.

TCriteria

The type of the criteria for the predicate.

Remarks

See FilterByIdentity<TKey, TIdentity, TState>(ReactiveCollection<TKey, TIdentity, TState>, Func<TIdentity, bool>) . A change to the criteria reports the keys that entered and left as inserts and removals, not as a reset, and a state edit still does not test the predicate. When more keys move than a list of them is worth, this stage builds again, at a cost of O(m log m) in the size of the upstream, and reports a reset.