AtomsSet<T> class

Namespace: Arlecchino.Atoms.Collections · Assembly: Arlecchino.Core

A set held as one piece of application state, behaving as a HashSet<T> does: adding what is already there changes nothing. A walk of it is in no order, so sort it where the reader sees the order.

public abstract class AtomsSet<T> : IReadableAtom<IReadOnlySet<T>>

Implements IReadableAtom<IReadOnlySet<T><T>>

Constructors

Member	Summary
AtomsSet(IReadOnlyList<T>, IEqualityComparer<T>)	Creates the set.

Properties

Member	Summary
Count	How many it holds.
IsEmpty	Whether it holds nothing.
RecordsHistory	Whether changes of this set enter the undo history.
Value	What the set holds now, as a live view rather than a copy. It is read-only all the way down, so every change goes through the members below.

Methods

Member	Summary
Add(T)	Puts something in. Putting in what is already there changes nothing.
Add(IReadOnlyList<T>)	Puts several in at once. One notification, one frame and one undo step for however many of them were not there already.
Clear()	Takes everything out. An empty set changes nothing.
Contains(T)	Whether the set holds something.
GetEnumerator()	Walks what the set holds, in no order it promises, so foreach over the set itself reads the way it does over a HashSet<T>. Reach for AtomsSet.Value where a sequence is what is wanted, LINQ included.
Remove(T)	Takes something out, and does nothing when it is not there.
Reset(IReadOnlyList<T>)	Replaces the contents in one go, for the set that is worked out again rather than edited — what a new listing marks, what a filter leaves. Contents equal to what is already there change nothing.
Subscribe(Action)	Calls back whenever the contents change.
TryAdd(T)	Puts something in and says whether it was new.
TryRemove(T)	Takes something out and says whether it was there.

Constructors in detail

AtomsSet(IReadOnlyList<T>, IEqualityComparer<T>)

public AtomsSet(IReadOnlyList<T> initial, IEqualityComparer<T> comparer);

Creates the set.

Parameters

Name	Type	Description
initial	IReadOnlyList<T><T>	What it starts with; empty when omitted. It is copied, not held.
comparer	IEqualityComparer<T><T>	How items are compared; the default comparer for T is used when omitted.

Properties in detail

Count

public int Count { get; }

How many it holds.

Type int

IsEmpty

public bool IsEmpty { get; }

Whether it holds nothing.

Type bool

RecordsHistory

public abstract bool RecordsHistory { get; }

Whether changes of this set enter the undo history.

Type bool

Value

public IReadOnlySet<T> Value { get; }

What the set holds now, as a live view rather than a copy. It is read-only all the way down, so every change goes through the members below.

Type IReadOnlySet<T><T>

Methods in detail

Add(T)

public void Add(T item);

Puts something in. Putting in what is already there changes nothing.

Parameters

Name	Type	Description
item	T	What to put in.

Add(IReadOnlyList<T>)

public void Add(IReadOnlyList<T> items);

Puts several in at once. One notification, one frame and one undo step for however many of them were not there already.

Parameters

Name	Type	Description
items	IReadOnlyList<T><T>	What to put in. Adding none, or only what is there, changes nothing.

Clear()

public void Clear();

Takes everything out. An empty set changes nothing.

Contains(T)

public bool Contains(T item);

Whether the set holds something.

Parameters

Name	Type	Description
item	T	What to look for.

Returns bool — true when it is there.

GetEnumerator()

public HashSet<T> GetEnumerator();

Walks what the set holds, in no order it promises, so foreach over the set itself reads the way it does over a HashSet<T>. Reach for AtomsSet.Value where a sequence is what is wanted, LINQ included.

Returns Enumerator<T><T> — The enumerator, which throws when the set changes while it is being walked.

Remove(T)

public void Remove(T item);

Takes something out, and does nothing when it is not there.

Parameters

Name	Type	Description
item	T	What to take out.

Reset(IReadOnlyList<T>)

public void Reset(IReadOnlyList<T> items);

Replaces the contents in one go, for the set that is worked out again rather than edited — what a new listing marks, what a filter leaves. Contents equal to what is already there change nothing.

Parameters

Name	Type	Description
items	IReadOnlyList<T><T>	What the set should hold instead.

Subscribe(Action)

public IDisposable Subscribe(Action listener);

Calls back whenever the contents change.

Parameters

Name	Type	Description
listener	Action	What to run on change.

Returns IDisposable — Dispose it to stop listening.

TryAdd(T)

public bool TryAdd(T item);

Puts something in and says whether it was new.

Parameters

Name	Type	Description
item	T	What to put in.

Returns bool — true when it went in, false when it was already there.

TryRemove(T)

public bool TryRemove(T item);

Takes something out and says whether it was there.

Parameters

Name	Type	Description
item	T	What to take out.

Returns bool — true when something was taken out.