Index: sdk/lib/async/stream.dart |
diff --git a/sdk/lib/async/stream.dart b/sdk/lib/async/stream.dart |
index 77230e8080d653552deba3287974492928c63ac1..bf7840912d8846ff2cf2b2a7ad3d12d7b3bef68f 100644 |
--- a/sdk/lib/async/stream.dart |
+++ b/sdk/lib/async/stream.dart |
@@ -14,12 +14,12 @@ typedef void _TimerCallback(); |
* A source of asynchronous data events. |
* |
* A Stream provides a way to receive a sequence of events. |
- * Each event is either a data event or an error event, |
- * representing the result of a single computation. |
- * When the events provided by a Stream have all been sent, |
- * a single "done" event will mark the end. |
+ * Each event is either a data event, also called an *element* of the stream, |
+ * or an error event, which is a notification that something has failed. |
+ * When a stream has emitted all its event, |
+ * a single "done" event will notify the listener that the end has been reached. |
* |
- * You can [listen] on a stream to make it start generating events, |
+ * You [listen] on a stream to make it start generating events, |
* and to set up listeners that receive the events. |
* When you listen, you receive a [StreamSubscription] object |
* which is the active object providing the events, |
@@ -118,18 +118,22 @@ abstract class Stream<T> { |
* |
* The stream reports the results of the futures on the stream in the order |
* in which the futures complete. |
+ * Each future provides either a data event or an error event, |
+ * depending on how the future completes. |
* |
- * If some futures have completed before calling `Stream.fromFutures`, |
- * their result will be output on the created stream in some unspecified |
- * order. |
+ * If some futures have already completed when `Stream.fromFutures` is called, |
+ * their results will be emitted in some unspecified order. |
* |
* When all futures have completed, the stream is closed. |
* |
- * If no future is passed, the stream closes as soon as possible. |
+ * If [futures] is empty, the stream closes as soon as possible. |
*/ |
factory Stream.fromFutures(Iterable<Future<T>> futures) { |
_StreamController<T> controller = new StreamController<T>(sync: true); |
int count = 0; |
+ // Declare these as variables holding closures instead of as |
+ // function declarations. |
+ // This avoids creating a new closure from the functions for each future. |
var onValue = (T value) { |
if (!controller.isClosed) { |
controller._add(value); |
@@ -342,10 +346,10 @@ abstract class Stream<T> { |
* If this stream closes and sends a done event, the [onDone] handler is |
* called. If [onDone] is `null`, nothing happens. |
* |
- * If [cancelOnError] is true, the subscription is automatically cancelled |
+ * If [cancelOnError] is true, the subscription is automatically canceled |
* when the first error event is delivered. The default is `false`. |
* |
- * While a subscription is paused, or when it has been cancelled, |
+ * While a subscription is paused, or when it has been canceled, |
* the subscription doesn't receive events and none of the |
* event handler functions are called. |
*/ |
@@ -353,11 +357,14 @@ abstract class Stream<T> { |
{Function onError, void onDone(), bool cancelOnError}); |
/** |
- * Creates a new stream from this stream that discards some data events. |
+ * Creates a new stream from this stream that discards some elements. |
* |
* The new stream sends the same error and done events as this stream, |
* but it only sends the data events that satisfy the [test]. |
* |
+ * If the [test] function throws, the data event is dropped and the |
+ * error is emitted on the returned stream instead. |
+ * |
* The returned stream is a broadcast stream if this stream is. |
* If a broadcast stream is listened to more than once, each subscription |
* will individually perform the `test`. |
@@ -367,12 +374,14 @@ abstract class Stream<T> { |
} |
/** |
+ * Transforms each element of this stream into a new stream event. |
+ * |
* Creates a new stream that converts each element of this stream |
- * to a new value using the [convert] function. |
+ * to a new value using the [convert] function, and emits the result. |
* |
* For each data event, `o`, in this stream, the returned stream |
* provides a data event with the value `convert(o)`. |
- * If [convert] throws, the returned stream reports the exception as an error |
+ * If [convert] throws, the returned stream reports it as an error |
* event instead. |
* |
* Error and done events are passed through unchanged to the returned stream. |
@@ -518,15 +527,20 @@ abstract class Stream<T> { |
} |
/** |
- * Creates a new stream with the events of a stream per original event. |
+ * Transforms each element into a sequence of asynchronous events. |
* |
- * This acts like [expand], except that [convert] returns a [Stream] |
- * instead of an [Iterable]. |
- * The events of the returned stream becomes the events of the returned |
- * stream, in the order they are produced. |
+ * Returns a new stream and for each event of this stream, do the following: |
* |
- * If [convert] returns `null`, no value is put on the output stream, |
- * just as if it returned an empty stream. |
+ * * If the event is an error event or a done event, it is emitted directly |
+ * by the returned stream. |
+ * * Otherwise it is an element. Then the [convert] function is called |
+ * with the element as argument to produce a convert-stream for the element. |
+ * * If that call throws, the error is emitted on the returned stream. |
+ * * If the call returnes `null`, no further action is taken for the elements. |
+ * * Otherwise, this stream is paused and convert-stream is listened to. |
+ * Every data and error event of the convert-stream is emitted on the returned |
+ * stream in the order it is produced. |
+ * When the convert-stream ends, this stream is resumed. |
* |
* The returned stream is a broadcast stream if this stream is. |
*/ |
@@ -595,6 +609,9 @@ abstract class Stream<T> { |
* If the error is intercepted, the [onError] function can decide what to do |
* with it. It can throw if it wants to raise a new (or the same) error, |
* or simply return to make the stream forget the error. |
+ * If the received `error` value is thrown again by the [onError] function, |
+ * it acts like a `rethrow` and it is emitted along with its original |
+ * stack trace, not the stack trace of the `throw` inside [onError]. |
* |
* If you need to transform an error into a data event, use the more generic |
* [Stream.transform] to handle the event by writing a data event to |
@@ -609,25 +626,32 @@ abstract class Stream<T> { |
} |
/** |
- * Creates a new stream from this stream that converts each element |
- * into zero or more events. |
+ * Transforms each element of this stream into a sequence of elements. |
* |
- * Each incoming event is converted to an [Iterable] of new events, |
- * and each of these new events are then sent by the returned stream |
- * in order. |
+ * Returns a new stream where each element of this stream is replaced |
+ * by zero or more data events. |
+ * The event values are proveded as an [Iterable] by a call to [convert] |
floitsch
2017/05/30 17:52:47
provided
|
+ * with the element as argument, and the elements of that iterable is |
+ * emitted in iteration order. |
+ * If calling [convert] throws, or if iteration of the returned values throws, |
floitsch
2017/05/30 17:52:47
if the iteration
|
+ * the error is emitted on the returned stream and iteration ends for that |
+ * element of this stream. |
+ * |
+ * Error events and the done event of this stream are forwarded directly |
+ * to the returned stream. |
* |
* The returned stream is a broadcast stream if this stream is. |
* If a broadcast stream is listened to more than once, each subscription |
* will individually call `convert` and expand the events. |
*/ |
- Stream<S> expand<S>(Iterable<S> convert(T value)) { |
+ Stream<S> expand<S>(Iterable<S> convert(T element)) { |
return new _ExpandStream<T, S>(this, convert); |
} |
/** |
- * Pipe the events of this stream into [streamConsumer]. |
+ * Pipes the events of this stream into [streamConsumer]. |
* |
- * The events of this stream are added to `streamConsumer` using |
+ * All events of this stream are added to `streamConsumer` using |
* [StreamConsumer.addStream]. |
* The `streamConsumer` is closed when this stream has been successfully added |
* to it - when the future returned by `addStream` completes without an error. |
@@ -637,29 +661,52 @@ abstract class Stream<T> { |
* |
* The returned future completes with the same result as the future returned |
* by [StreamConsumer.close]. |
- * If the adding of the stream itself fails in some way, |
- * then the consumer is expected to be closed, and won't be closed again. |
- * In that case the returned future completes with the error from calling |
- * `addStream`. |
+ * If the call to [StreamConsumer.addStream] fails in some way, this |
+ * method fails in the same way. |
*/ |
Future pipe(StreamConsumer<T> streamConsumer) { |
return streamConsumer.addStream(this).then((_) => streamConsumer.close()); |
} |
/** |
- * Chains this stream as the input of the provided [StreamTransformer]. |
+ * Applies a [StreamTransformer] to the current stream. |
* |
- * Returns the result of [:streamTransformer.bind:] itself. |
+ * Returns the result of the stream transformation, |
+ * that is, the result of `streamTransformer.bind(this)`. |
+ * This method simply allows writing the call to `streamTransformer.bind` |
+ * in a chained fashion, like |
+ * ``` |
+ * stream.map(mapping).transform(transformation).toList() |
+ * ``` |
+ * which can be more convenient than calling `bind` directly. |
* |
- * The `streamTransformer` can decide whether it wants to return a |
- * broadcast stream or not. |
+ * The [streamTransformer] can return any stream. |
+ * Whether the returned stream is a broadcast stream or not, |
+ * and which elements it will contain, |
+ * is entirely up to the transformation. |
*/ |
Stream<S> transform<S>(StreamTransformer<T, S> streamTransformer) { |
return streamTransformer.bind(this); |
} |
/** |
- * Reduces a sequence of values by repeatedly applying [combine]. |
+ * Combines a sequence of values by repeatedly applying [combine]. |
+ * |
+ * Similar to [Iterable.reduce], this function maintains a value, |
+ * starting with the first element of the stream |
+ * and updated for each further element of this stream. |
+ * For each element after the first, |
+ * the value is updated to the result of calling [combine] |
+ * with the previous value and the element. |
+ * |
+ * When this stream is done, the returned future is completed with |
+ * the value at that time. |
+ * |
+ * If the stream is empty, the returned future is completed with |
+ * an error. |
+ * If this stream emits an error, or the call to [combine] throws, |
+ * the returned future is completed with that error, |
+ * and processing is stopped. |
*/ |
Future<T> reduce(T combine(T previous, T element)) { |
_Future<T> result = new _Future<T>(); |
@@ -681,6 +728,9 @@ abstract class Stream<T> { |
onDone: () { |
if (!seenFirst) { |
try { |
+ // Throw and recatch, instead of just doing |
+ // _completeWithErrorCallback, e, theError, StackTrace.current), |
+ // to ensure that the stackTrace is set on the error. |
throw IterableElementError.noElement(); |
} catch (e, s) { |
_completeWithErrorCallback(result, e, s); |
@@ -693,32 +743,54 @@ abstract class Stream<T> { |
return result; |
} |
- /** Reduces a sequence of values by repeatedly applying [combine]. */ |
+ /** |
+ * Combines a sequence of values by repeatedly applying [combine]. |
+ * |
+ * Similar to [Iterable.fold], this function maintains a value, |
+ * starting with [initialValue] and updated for each element of |
+ * this stream. |
+ * For each element, the value is updated to the result of calling |
+ * [combine] with the previous value and the element. |
+ * |
+ * When this stream is done, the returned future is completed with |
+ * the value at that time. |
+ * For an empty stream, the future is completed with [initialValue]. |
+ * |
+ * If this stream emits an error, or the call to [combine] throws, |
+ * the returned future is completed with that error, |
+ * and processing is stopped. |
+ */ |
Future<S> fold<S>(S initialValue, S combine(S previous, T element)) { |
_Future<S> result = new _Future<S>(); |
S value = initialValue; |
StreamSubscription subscription; |
- subscription = this.listen((T element) { |
- _runUserCode(() => combine(value, element), (S newValue) { |
- value = newValue; |
- }, _cancelAndErrorClosure(subscription, result)); |
- }, onError: (e, st) { |
- result._completeError(e, st); |
- }, onDone: () { |
- result._complete(value); |
- }, cancelOnError: true); |
+ subscription = this.listen( |
+ (T element) { |
+ _runUserCode(() => combine(value, element), (S newValue) { |
+ value = newValue; |
+ }, _cancelAndErrorClosure(subscription, result)); |
+ }, |
+ onError: result._completeError, |
+ onDone: () { |
+ result._complete(value); |
+ }, |
+ cancelOnError: true); |
return result; |
} |
/** |
- * Collects string of data events' string representations. |
+ * Combines the string representation of elements into a single string. |
+ * |
+ * Each element is converted to a string using its [Object.toString] method. |
+ * If [separator] is provided, it is inserted between element string |
+ * representations. |
* |
- * If [separator] is provided, it is inserted between any two |
- * elements. |
+ * The returned future is completed with the combined string when the stream |
+ * is done. |
* |
- * Any error in the stream causes the future to complete with that |
- * error. Otherwise it completes with the collected string when |
- * the "done" event arrives. |
+ * If the stream contains an error, or if the call to [Object.toString] |
+ * throws, the returned future is completed with that error, |
+ * and processing stops. |
*/ |
Future<String> join([String separator = ""]) { |
_Future<String> result = new _Future<String>(); |
@@ -744,10 +816,15 @@ abstract class Stream<T> { |
} |
/** |
- * Checks whether [needle] occurs in the elements provided by this stream. |
+ * Returns whether [needle] occurs in the elements provided by this stream. |
+ * |
+ * Compares each element of this stream to [needle] using [Object.==]. |
+ * If an equal element is found, the returned future is completed with `true`. |
+ * If the stream ends without finding a match, the future is completed with |
+ * `false`. |
* |
- * Completes the [Future] when the answer is known. |
- * If this stream reports an error, the [Future] will report that error. |
+ * If the stream contains an error, or the call to `Object.==` throws, |
+ * the returned future is completed with that error, and processing stops. |
*/ |
Future<bool> contains(Object needle) { |
_Future<bool> future = new _Future<bool>(); |
@@ -769,11 +846,13 @@ abstract class Stream<T> { |
} |
/** |
- * Executes [action] on each data event of the stream. |
+ * Executes [action] on each element of the stream. |
* |
- * Completes the returned [Future] when all events of the stream |
- * have been processed. Completes the future with an error if the |
- * stream has an error event, or if [action] throws. |
+ * Completes the returned [Future] when all elements of the stream |
+ * have been processed. |
+ * |
+ * If the stream contains an error, or if the call to [action] throws, |
+ * the returne future completes with that error, and processing stops. |
*/ |
Future forEach(void action(T element)) { |
_Future future = new _Future(); |
@@ -795,8 +874,15 @@ abstract class Stream<T> { |
/** |
* Checks whether [test] accepts all elements provided by this stream. |
* |
- * Completes the [Future] when the answer is known. |
- * If this stream reports an error, the [Future] will report that error. |
+ * Calls [test] on each element of the stream. |
+ * If the call returns `false`, the returned future is completed with `false` |
+ * and processing stops. |
+ * |
+ * If the stream ends without finding an element that [test] rejects, |
+ * the returned future is completed with `true`. |
+ * |
+ * If this stream contains an error, or if the call to [test] throws, |
+ * the returned future is completed with that error, and processing stops. |
*/ |
Future<bool> every(bool test(T element)) { |
_Future<bool> future = new _Future<bool>(); |
@@ -820,16 +906,15 @@ abstract class Stream<T> { |
/** |
* Checks whether [test] accepts any element provided by this stream. |
* |
- * Completes the [Future] when the answer is known. |
- * |
- * If this stream reports an error, the [Future] reports that error. |
+ * Calls [test] on each element of the stream. |
+ * If the call returns `true`, the returned future is completed with `true` |
+ * and processing stops. |
* |
- * Stops listening to the stream after the first matching element has been |
- * found. |
+ * If the stream ends without finding an element that [test] accepts, |
+ * the returned future is completed with `false`. |
* |
- * Internally the method cancels its subscription after this element. This |
- * means that single-subscription (non-broadcast) streams are closed and |
- * cannot be reused after a call to this method. |
+ * If this stream contains an error, or if the call to [test] throws, |
+ * the returned future is completed with that error, and processing stops. |
*/ |
Future<bool> any(bool test(T element)) { |
_Future<bool> future = new _Future<bool>(); |
@@ -850,7 +935,18 @@ abstract class Stream<T> { |
return future; |
} |
- /** Counts the elements in the stream. */ |
+ /** |
+ * The number of elements in this stream. |
+ * |
+ * Waits for all elements of this stream. When the stream ends, |
+ * the returned future is completed with the number of elements. |
+ * |
+ * If the stream contains an error, the returned future is completed with |
+ * that error, and processing stops. |
+ * |
+ * This operation listens to the stream, and a non-broadcast stream cannot |
+ * be reused after finding its length. |
+ */ |
Future<int> get length { |
_Future<int> future = new _Future<int>(); |
int count = 0; |
@@ -867,13 +963,18 @@ abstract class Stream<T> { |
} |
/** |
- * Reports whether this stream contains any elements. |
+ * Whether this stream contains any elements. |
* |
- * Stops listening to the stream after the first element has been received. |
+ * Waits for the first element of this stream, then completes the returned |
+ * future with `true`. |
+ * If the stream ends without emitting any elements, the returned future is |
+ * completed with `false`. |
* |
- * Internally the method cancels its subscription after the first element. |
- * This means that single-subscription (non-broadcast) streams are closed and |
- * cannot be reused after a call to this getter. |
+ * If the first event is an error, the returned future is completed with that |
+ * error. |
+ * |
+ * This operation listens to the stream, and a non-broadcast stream cannot |
+ * be reused after checking whether it is empty. |
*/ |
Future<bool> get isEmpty { |
_Future<bool> future = new _Future<bool>(); |
@@ -890,7 +991,16 @@ abstract class Stream<T> { |
return future; |
} |
- /** Collects the data of this stream in a [List]. */ |
+ /** |
+ * Collects all elements of this stream in a [List]. |
+ * |
+ * Creates a `List<T>` and adds all elements of the stream to the list |
+ * in the order they arrive. |
+ * When the stream ends, the returned future is completed with that list. |
+ * |
+ * If the stream contains an error, the returned future is completed |
+ * with that error, and processing stops. |
+ */ |
Future<List<T>> toList() { |
List<T> result = <T>[]; |
_Future<List<T>> future = new _Future<List<T>>(); |
@@ -1042,7 +1152,7 @@ abstract class Stream<T> { |
} |
/** |
- * Returns the first element of the stream. |
+ * The first element of the stream. |
* |
* Stops listening to the stream after the first element has been received. |
* |
@@ -1050,14 +1160,14 @@ abstract class Stream<T> { |
* This means that single-subscription (non-broadcast) streams are closed |
* and cannot be reused after a call to this getter. |
* |
- * If an error event occurs before the first data event, the resulting future |
+ * If an error event occurs before the first data event, the returned future |
* is completed with that error. |
* |
* If this stream is empty (a done event occurs before the first data event), |
- * the resulting future completes with a [StateError]. |
+ * the returned future completes with an error. |
* |
* Except for the type of the error, this method is equivalent to |
- * [:this.elementAt(0):]. |
+ * `this.elementAt(0)`. |
*/ |
Future<T> get first { |
_Future<T> future = new _Future<T>(); |
@@ -1079,13 +1189,14 @@ abstract class Stream<T> { |
} |
/** |
- * Returns the last element of the stream. |
+ * The last element of this stream. |
* |
- * If an error event occurs before the first data event, the resulting future |
- * is completed with that error. |
+ * If this stream emits an error event, |
+ * the returned future is completed with that error |
+ * and processing stops. |
* |
- * If this stream is empty (a done event occurs before the first data event), |
- * the resulting future completes with a [StateError]. |
+ * If this stream is empty (the done event is the first event), |
+ * the returned future completes with an error. |
*/ |
Future<T> get last { |
_Future<T> future = new _Future<T>(); |
@@ -1113,12 +1224,14 @@ abstract class Stream<T> { |
} |
/** |
- * Returns the single element. |
+ * The single element of this stream. |
* |
- * If an error event occurs before or after the first data event, the |
- * resulting future is completed with that error. |
+ * If this stream emits an error event, |
+ * the returned future is completed with that error |
+ * and processing stops. |
* |
- * If [this] is empty or has more than one element throws a [StateError]. |
+ * If [this] is empty or has more than one element, |
+ * the returned future completes with an error. |
*/ |
Future<T> get single { |
_Future<T> future = new _Future<T>(); |
@@ -1158,23 +1271,27 @@ abstract class Stream<T> { |
/** |
* Finds the first element of this stream matching [test]. |
* |
- * Returns a future that is filled with the first element of this stream |
- * that [test] returns true for. |
+ * Returns a future that is completed with the first element of this stream |
+ * that [test] returns `true` for. |
* |
* If no such element is found before this stream is done, and a |
* [defaultValue] function is provided, the result of calling [defaultValue] |
- * becomes the value of the future. |
+ * becomes the value of the future. If [defaultValue] throws, the returned |
+ * future is completed with that error. |
* |
- * Stops listening to the stream after the first matching element has been |
- * received. |
+ * If this stream emits an error before the first matching element, |
+ * the returned future is completed with that error, and processing stops. |
+ * |
+ * Stops listening to the stream after the first matching element or error |
+ * has been received. |
* |
* Internally the method cancels its subscription after the first element that |
* matches the predicate. This means that single-subscription (non-broadcast) |
* streams are closed and cannot be reused after a call to this method. |
* |
* If an error occurs, or if this stream ends without finding a match and |
- * with no [defaultValue] function provided, the future will receive an |
- * error. |
+ * with no [defaultValue] function provided, |
+ * the returned future is completed with an error. |
*/ |
Future<dynamic> firstWhere(bool test(T element), {Object defaultValue()}) { |
_Future<dynamic> future = new _Future(); |
@@ -1206,8 +1323,12 @@ abstract class Stream<T> { |
/** |
* Finds the last element in this stream matching [test]. |
* |
- * As [firstWhere], except that the last matching element is found. |
- * That means that the result cannot be provided before this stream |
+ * If this stream emits an error, the returned future is completed with that |
+ * error, and processing stops. |
+ * |
+ * Otherwise as [firstWhere], except that the last matching element is found |
+ * instead of the first. |
+ * That means that a non-error result cannot be provided before this stream |
* is done. |
*/ |
Future<dynamic> lastWhere(bool test(T element), {Object defaultValue()}) { |
@@ -1463,26 +1584,44 @@ abstract class StreamSubscription<T> { |
Future cancel(); |
/** |
- * Set or override the data event handler of this subscription. |
+ * Replaces the data event handler of this subscription. |
+ * |
+ * The [handleData] function is called for each element of the stream |
+ * after this function is called. |
+ * If [handleData] is `null`, further elements are ignored. |
* |
- * This method overrides the handler that has been set at the invocation of |
- * [Stream.listen]. |
+ * This method replaces the current handler set by the invocation of |
+ * [Stream.listen] or by a previous call to [onData]. |
*/ |
void onData(void handleData(T data)); |
/** |
- * Set or override the error event handler of this subscription. |
+ * Replaces the error event handler of this subscription. |
* |
- * This method overrides the handler that has been set at the invocation of |
- * [Stream.listen] or by calling [asFuture]. |
+ * The [handleError] function must be able to be called with either |
+ * one positional argument, or with two positional arguments |
+ * where the seconds is always a [StackTrace]. |
+ * |
+ * The [handleError] argument may be `null`, in which case further |
+ * error events are considered unhandled, and will be reported to |
+ * [Zone.handleUncaughtError]. |
+ * |
+ * The provided function is called for all error events from the |
+ * stream subscription. |
+ * |
+ * This method replaces the current handler set by the invocation of |
+ * [Stream.listen], by calling [asFuture], or by a previous call to [onError]. |
*/ |
void onError(Function handleError); |
/** |
- * Set or override the done event handler of this subscription. |
+ * Replaces the done event handler of this subscription. |
+ * |
+ * The [handleDone] function is called when the stream closes. |
+ * The value may be `null`, in which case no function is called. |
* |
- * This method overrides the handler that has been set at the invocation of |
- * [Stream.listen] or by calling [asFuture]. |
+ * This method reaplces the current handler set by the invocation of |
+ * [Stream.listen], by calling [asFuture], or by a previous call to [onDone]. |
*/ |
void onDone(void handleDone()); |
@@ -1492,16 +1631,19 @@ abstract class StreamSubscription<T> { |
* While paused, the subscription will not fire any events. |
* If it receives events from its source, they will be buffered until |
* the subscription is resumed. |
- * The underlying source is usually informed about the pause, |
+ * For non-broadcast streams, the underlying source is usually informed |
+ * about the pause, |
* so it can stop generating events until the subscription is resumed. |
* |
* To avoid buffering events on a broadcast stream, it is better to |
* cancel this subscription, and start to listen again when events |
- * are needed. |
+ * are needed, if the intermediate events are not important. |
* |
- * If [resumeSignal] is provided, the stream will undo the pause |
- * when the future completes. If the future completes with an error, |
- * the stream will resume, but the error will not be handled! |
+ * If [resumeSignal] is provided, the stream subscription will undo the pause |
+ * when the future completes, as if by a call to [resume]. |
+ * If the future completes with an error, |
+ * the stream will still resume, but the error will be considered unhandled |
+ * and is passed to [Zone.handleUncaughtError]. |
* |
* A call to [resume] will also undo a pause. |
* |
@@ -1515,11 +1657,23 @@ abstract class StreamSubscription<T> { |
/** |
* Resume after a pause. |
+ * |
+ * This undoes one previous call to [pause]. |
+ * When all previously calls to [pause] have been matched by a calls to |
+ * [resume], possibly through a `resumeSignal` passed to [pause], |
+ * the stream subscription may emit events again. |
*/ |
void resume(); |
/** |
- * Returns true if the [StreamSubscription] is paused. |
+ * Whether the [StreamSubscription] is currently paused. |
+ * |
+ * If there have been more calls to [pause] than to [resume] on this |
+ * stream subscription, the subscription is paused, and this getter |
+ * returns `true`. |
+ * |
+ * Returns `false` if the stream can currently emit events, or if |
+ * the subscription has completed or been cancelled. |
*/ |
bool get isPaused; |
@@ -1692,7 +1846,7 @@ abstract class StreamSink<S> implements EventSink<S>, StreamConsumer<S> { |
* |
* * all events have been processed and the sink has been closed, or |
* * the sink has otherwise been stopped from handling more events |
- * (for example by cancelling a stream subscription). |
+ * (for example by canceling a stream subscription). |
*/ |
Future get done; |
} |
@@ -1914,10 +2068,10 @@ class _ControllerEventSinkWrapper<T> implements EventSink<T> { |
} |
} |
-/// A group created by [Stream.groupBy] or [Stream.groupByMapped]. |
+/// A group created by [Stream.groupBy]. |
/// |
-/// The stream created by `groupBy` emits a `GroupedEvents` for each distinct key |
-/// it encounters. |
+/// The stream created by `groupBy` emits a `GroupedEvents` |
+/// for each distinct key it encounters. |
/// This group contains the [key] itself, along with a stream of the [values] |
/// associated with that key. |
class GroupedEvents<K, V> { |