LazyStream<T> class

A Stream wrapper that forwards to another Stream that's initialized lazily.

This class allows a concrete Stream to be created only once it has a listener. It's useful to wrapping APIs that do expensive computation to produce a Stream.

Inheritance

Constructors

LazyStream(FutureOr<Stream<T>> callback())
Creates a single-subscription Stream that calls callback when it gets a listener and forwards to the returned stream.

Properties

first → Future<T>
The first element of this stream. [...]
read-only, inherited
hashCode → int
The hash code for this object. [...]
read-only, inherited
isBroadcast → bool
Whether this stream is a broadcast stream.
read-only, inherited
isEmpty → Future<bool>
Whether this stream contains any elements. [...]
read-only, inherited
last → Future<T>
The last element of this stream. [...]
read-only, inherited
length → Future<int>
The number of elements in this stream. [...]
read-only, inherited
runtimeType → Type
A representation of the runtime type of the object.
read-only, inherited
single → Future<T>
The single element of this stream. [...]
read-only, inherited

Methods

listen(void onData(T event), { Function onError, void onDone(), bool cancelOnError }) → StreamSubscription<T>
Adds a subscription to this stream. [...]
override
any(bool test(T element)) → Future<bool>
Checks whether test accepts any element provided by this stream. [...]
inherited
asBroadcastStream({void onListen(StreamSubscription<T> subscription), void onCancel(StreamSubscription<T> subscription) }) → Stream<T>
Returns a multi-subscription stream that produces the same events as this. [...]
inherited
asyncExpand<E>(Stream<E> convert(T event)) → Stream<E>
Transforms each element into a sequence of asynchronous events. [...]
inherited
asyncMap<E>(FutureOr<E> convert(T event)) → Stream<E>
Creates a new stream with each data event of this stream asynchronously mapped to a new event. [...]
inherited
cast<R>() → Stream<R>
Adapt this stream to be a Stream<R>. [...]
inherited
contains(Object needle) → Future<bool>
Returns whether needle occurs in the elements provided by this stream. [...]
inherited
distinct([bool equals(T previous, T next) ]) → Stream<T>
Skips data events if they are equal to the previous data event. [...]
inherited
drain<E>([E futureValue ]) → Future<E>
Discards all data on this stream, but signals when it is done or an error occurred. [...]
inherited
elementAt(int index) → Future<T>
Returns the value of the indexth data event of this stream. [...]
inherited
every(bool test(T element)) → Future<bool>
Checks whether test accepts all elements provided by this stream. [...]
inherited
expand<S>(Iterable<S> convert(T element)) → Stream<S>
Transforms each element of this stream into a sequence of elements. [...]
inherited
firstWhere(bool test(T element), { T orElse() }) → Future<T>
Finds the first element of this stream matching test. [...]
inherited
fold<S>(S initialValue, S combine(S previous, T element)) → Future<S>
Combines a sequence of values by repeatedly applying combine. [...]
inherited
forEach(void action(T element)) → Future
Executes action on each element of this stream. [...]
inherited
handleError(Function onError, { bool test(dynamic error) }) → Stream<T>
Creates a wrapper Stream that intercepts some errors from this stream. [...]
inherited
join([String separator = "" ]) → Future<String>
Combines the string representation of elements into a single string. [...]
inherited
lastWhere(bool test(T element), { T orElse() }) → Future<T>
Finds the last element in this stream matching test. [...]
inherited
map<S>(S convert(T event)) → Stream<S>
Transforms each element of this stream into a new stream event. [...]
inherited
noSuchMethod(Invocation invocation) → dynamic
Invoked when a non-existent method or property is accessed. [...]
inherited
pipe(StreamConsumer<T> streamConsumer) → Future
Pipes the events of this stream into streamConsumer. [...]
inherited
reduce(T combine(T previous, T element)) → Future<T>
Combines a sequence of values by repeatedly applying combine. [...]
inherited
singleWhere(bool test(T element), { T orElse() }) → Future<T>
Finds the single element in this stream matching test. [...]
inherited
skip(int count) → Stream<T>
Skips the first count data events from this stream. [...]
inherited
skipWhile(bool test(T element)) → Stream<T>
Skip data events from this stream while they are matched by test. [...]
inherited
take(int count) → Stream<T>
Provides at most the first count data events of this stream. [...]
inherited
takeWhile(bool test(T element)) → Stream<T>
Forwards data events while test is successful. [...]
inherited
timeout(Duration timeLimit, { void onTimeout(EventSink<T> sink) }) → Stream<T>
Creates a new stream with the same events as this stream. [...]
inherited
toList() → Future<List<T>>
Collects all elements of this stream in a List. [...]
inherited
toSet() → Future<Set<T>>
Collects the data of this stream in a Set. [...]
inherited
toString() → String
Returns a string representation of this object.
inherited
transform<S>(StreamTransformer<T, S> streamTransformer) → Stream<S>
Applies streamTransformer to this stream. [...]
inherited
where(bool test(T event)) → Stream<T>
Creates a new stream from this stream that discards some elements. [...]
inherited

Operators

operator ==(dynamic other) → bool
The equality operator. [...]
inherited