ZonedWork<T> class

A ZonedWork is an operation for executing a computation inside the Zone container with the possibility of externally controlled termination.

/ The recommended way to terminate a ZonedWork is to request a cancellation using a cancellation token.

⚠️ Warning:
The following warnings concern the various consequences of terminating ZonedWork using the terminate method.

Because ZonedWork runs in a separate zone with its own uncaught errors handler ZoneSpecification.handleUncaughtError due to limitations of the Dart SDK, when using such a handler, in some cases, errors from the parent zone may not leave the parent zone and may lead to the fact that it will be physically impossible to catch them (and shut down the Zone correctly).

More detailed information can be found here:

Termination is implemented by attempting to stop code execution in various ways (this does not apply to voluntary termination using a cancellation token) and includes the following actions:

  • Canceling timers
  • Replacing timer handlers with empty callbacks
  • Replacing microtasks with empty callbacks
  • Replacing registered callbacks that allow null returns with empty callbacks

When using objects created before ZonedWork was created, these objects may cause memory leaks.
Example: If (inside ZonedWork) subscribe to a broadcast stream created before the creation of ZonedWork, and then terminate ZonedWork by calling the terminate method, the subscription will never be canceled.

Implemented types

Constructors

ZonedWork(FutureOr<T> computation(), {CancellationToken? token})
Creates an instance of ZonedWork.

Properties

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

Methods

noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
run() → Future<T>
Executes the computation and returns the computation result (or throws the exception), or throws the CancellationException exception.
override
terminate({bool force = false}) → void
Requests to terminate the execution of a computation.
override
toString() → String
A string representation of this object.
inherited

Operators

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

Static Properties

current → ZonedWork<Object?>?
Returns an instance of the current ZonedWork or null.
no setter

Static Methods

onExit(FutureOr<void> handler(ZonedWork<Object?> work)) → bool
Adds an onExit handler to the current ZonedWork instance; if the handler has already been added previously or there is no current ZonedWork instance, then throws a StateError exception.
withArgument<T, R>(T argument, FutureOr<R> computation(T arg), {CancellationToken? token}) → ZonedWork<R>
Creates an instance of ZonedWork.