StreamTransformer<S, T> class abstract interface

Transforms a Stream.

When a stream's Stream.transform method is invoked with a StreamTransformer, the stream calls the bind method on the provided transformer. The resulting stream is then returned from the Stream.transform method.

Conceptually, a transformer is simply a function from Stream to Stream that is encapsulated into a class.

It is good practice to write transformers that can be used multiple times.

All other transforming methods on Stream, such as, Stream.where or Stream.expand can be implemented using Stream.transform. A StreamTransformer is thus very powerful but often also a bit more complicated to use.

The StreamTransformer.fromHandlers constructor allows passing separate callbacks to react to events, errors, and the end of the stream. The StreamTransformer.fromBind constructor creates a StreamTransformer whose bind method is implemented by calling the function passed to the constructor.



StreamTransformer(StreamSubscription<T> onListen(Stream<S> stream, bool cancelOnError))
Creates a StreamTransformer based on the given onListen callback.
StreamTransformer.fromBind(Stream<T> bind(Stream<S>))
Creates a StreamTransformer based on a bind callback.
StreamTransformer.fromHandlers({void handleData(S data, EventSink<T> sink)?, void handleError(Object error, StackTrace stackTrace, EventSink<T> sink)?, void handleDone(EventSink<T> sink)?})
Creates a StreamTransformer that delegates events to the given functions.


hashCode int
The hash code for this object.
no setterinherited
runtimeType Type
A representation of the runtime type of the object.
no setterinherited


bind(Stream<S> stream) Stream<T>
Transforms the provided stream.
cast<RS, RT>() StreamTransformer<RS, RT>
Provides a StreamTransformer<RS, RT> view of this stream transformer.
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
toString() String
A string representation of this object.


operator ==(Object other) bool
The equality operator.

Static Methods

castFrom<SS, ST, TS, TT>(StreamTransformer<SS, ST> source) StreamTransformer<TS, TT>
Adapts source to be a StreamTransformer<TS, TT>.