NullStreamSink<T> class

A StreamSink that discards all events.

The sink silently drops events until close is called, at which point it throws StateErrors when events are added. This is the same behavior as a sink whose remote end has closed, such as when a WebSocket connection has been closed.

This can be used when a sink is needed but no events are actually intended to be added. The new NullStreamSink.error constructor can be used to represent errors when creating a sink, since StreamSink.done exposes sink errors. For example:

StreamSink<List<int>> openForWrite(String filename) {
  try {
    return new RandomAccessSink(new File(filename).openSync());
  } on IOException catch (error, stackTrace) {
    return new NullStreamSink.error(error, stackTrace);
  }
}

Constructors

NullStreamSink({Future done })
Creates a null sink. [...]
NullStreamSink.error(dynamic error, [ StackTrace stackTrace ])
Creates a null sink whose done future emits error. [...]

Properties

done → Future
Return a future which is completed when the StreamSink is finished. [...]
final
hashCode → int
The hash code for this object.
read-only, inherited
runtimeType → Type
A representation of the runtime type of the object.
read-only, inherited

Methods

add(T data) → void
Adds a data event to the sink. [...]
addError(Object error, [ StackTrace stackTrace ]) → void
Adds an error to the sink. [...]
addStream(Stream<T> stream) → Future
Consumes the elements of stream. [...]
close() → Future
Tells the stream sink that no further streams will be added. [...]
noSuchMethod(Invocation invocation) → dynamic
Invoked when a non-existent method or property is accessed.
inherited
toString() → String
Returns a string representation of this object.
inherited

Operators

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