blob: 591f9031d7160999bb4f2826c3108d90efa87ab3 [file] [log] [blame]
// Copyright (c) 2015, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
import 'dart:async';
/// Simple delegating wrapper around a [StreamConsumer].
/// Subclasses can override individual methods, or use this to expose only the
/// [StreamConsumer] methods of a subclass.
class DelegatingStreamConsumer<T> implements StreamConsumer<T> {
final StreamConsumer _consumer;
/// Create a delegating consumer forwarding calls to [consumer].
DelegatingStreamConsumer(StreamConsumer<T> consumer) : _consumer = consumer;
/// Creates a wrapper that coerces the type of [consumer].
/// Unlike [new StreamConsumer], this only requires its argument to be an
/// instance of `StreamConsumer`, not `StreamConsumer<T>`. This means that
/// calls to [addStream] may throw a [CastError] if the argument type doesn't
/// match the reified type of [consumer].
static StreamConsumer<T> typed<T>(StreamConsumer consumer) =>
consumer is StreamConsumer<T>
? consumer
: DelegatingStreamConsumer._(consumer);
Future addStream(Stream<T> stream) => _consumer.addStream(stream);
Future close() => _consumer.close();