AtomsQueue<T> class

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

A queue held as one piece of application state, joined at the back and left from the front. It is touched only by the drawing thread, so background work hands its item over with FrameThread.Post.

public abstract class AtomsQueue<T> : IReadableAtom<IReadOnlyList<T>>

Implements IReadableAtom<IReadOnlyList<T><T>>

Constructors

Member	Summary
AtomsQueue(IReadOnlyList<T>)	Creates the queue.

Properties

Member	Summary
Count	How many are waiting.
IsEmpty	Whether nothing is waiting.
RecordsHistory	Whether changes of this queue enter the undo history.
Value	What is waiting now, front first, 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
Clear()	Drops everything waiting. An empty queue changes nothing.
Dequeue()	Takes the one at the front, and throws when nothing is waiting.
Enqueue(T)	Puts something at the back.
Enqueue(IReadOnlyList<T>)	Puts several at the back at once, in the order given. One notification, one frame and one undo step for the lot.
GetEnumerator()	Walks what is waiting, front first, so foreach over the queue itself reads the way it does over a list. Reach for AtomsQueue.Value where a sequence is what is wanted, LINQ included.
Peek()	Reads the one at the front without taking it, and throws when nothing is waiting.
Reset(IReadOnlyList<T>)	Replaces what is waiting in one go, for a queue that is rebuilt rather than worked through — a plan worked out again, a batch reordered. Contents equal to what is already there change nothing.
Subscribe(Action)	Calls back whenever what is waiting changes.
TryDequeue(out T)	Takes the one at the front without throwing when nothing is waiting.
TryPeek(out T)	Reads the one at the front without taking it or throwing.

Constructors in detail

AtomsQueue(IReadOnlyList<T>)

public AtomsQueue(IReadOnlyList<T> initial);

Creates the queue.

Parameters

Name	Type	Description
initial	IReadOnlyList<T><T>	What is already waiting, front first; empty when omitted. It is copied, not held.

Properties in detail

Count

public int Count { get; }

How many are waiting.

Type int

IsEmpty

public bool IsEmpty { get; }

Whether nothing is waiting.

Type bool

RecordsHistory

public abstract bool RecordsHistory { get; }

Whether changes of this queue enter the undo history.

Type bool

Value

public IReadOnlyList<T> Value { get; }

What is waiting now, front first, 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 IReadOnlyList<T><T>

Methods in detail

Clear()

public void Clear();

Drops everything waiting. An empty queue changes nothing.

Dequeue()

public T Dequeue();

Takes the one at the front, and throws when nothing is waiting.

Returns T — What was at the front.

Enqueue(T)

public void Enqueue(T item);

Puts something at the back.

Parameters

Name	Type	Description
item	T	What to add.

Enqueue(IReadOnlyList<T>)

public void Enqueue(IReadOnlyList<T> items);

Puts several at the back at once, in the order given. One notification, one frame and one undo step for the lot.

Parameters

Name	Type	Description
items	IReadOnlyList<T><T>	What to add. Adding none changes nothing.

GetEnumerator()

public List<T> GetEnumerator();

Walks what is waiting, front first, so foreach over the queue itself reads the way it does over a list. Reach for AtomsQueue.Value where a sequence is what is wanted, LINQ included.

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

Peek()

public T Peek();

Reads the one at the front without taking it, and throws when nothing is waiting.

Returns T — What is at the front.

Reset(IReadOnlyList<T>)

public void Reset(IReadOnlyList<T> items);

Replaces what is waiting in one go, for a queue that is rebuilt rather than worked through — a plan worked out again, a batch reordered. Contents equal to what is already there change nothing.

Parameters

Name	Type	Description
items	IReadOnlyList<T><T>	What should be waiting instead, front first.

Subscribe(Action)

public IDisposable Subscribe(Action listener);

Calls back whenever what is waiting changes.

Parameters

Name	Type	Description
listener	Action	What to run on change.

Returns IDisposable — Dispose it to stop listening.

TryDequeue(out T)

public bool TryDequeue(out T item);

Takes the one at the front without throwing when nothing is waiting.

Parameters

Name	Type	Description
item	T	What was at the front, when there was one.

Returns bool — true when something was taken.

TryPeek(out T)

public bool TryPeek(out T item);

Reads the one at the front without taking it or throwing.

Parameters

Name	Type	Description
item	T	What is at the front, when there is one.

Returns bool — true when there was one.