Class webdriver.promise.ControlFlow

Extends .

Defined in: promise.js.

Class Summary
Constructor Attributes	Constructor Name and Description
	webdriver.promise.ControlFlow(opt_timer) Handles the execution of scheduled tasks, each of which may be an asynchronous operation.

Field Summary
Field Attributes	Field Name and Description
<static>	webdriver.promise.ControlFlow.defaultTimer The default timer object, which uses the global timer functions.
<static>	webdriver.promise.ControlFlow.EVENT_LOOP_FREQUENCY How often, in milliseconds, the event loop should run.
<static>	webdriver.promise.ControlFlow.EventType Events that may be emitted by an webdriver.promise.ControlFlow.
	timer The timer used by this instance.

Method Summary
Method Attributes	Method Name and Description
	annotateError(e) Appends a summary of this instance's recent task history to the given error's stack trace.
	await(promise) Schedules a task that will wait for another promise to resolve.
	clearHistory() Clears this instance's task history.
	execute(fn, opt_description) Schedules a task for execution.
	getHistory() Returns a summary of the recent task activity for this instance.
	getSchedule()
	reset() Resets this instance, clearing its queue and removing all event listeners.
	timeout(ms, opt_description) Inserts a {@code setTimeout} into the command queue.
	wait(condition, timeout, opt_message) Schedules a task that shall wait for a condition to hold.

Class Detail

webdriver.promise.ControlFlow(opt_timer)

Handles the execution of scheduled tasks, each of which may be an asynchronous operation. The control flow will ensure tasks are executed in the ordered scheduled, starting each task only once those before it have completed.

Each task scheduled within this flow may return a webdriver.promise.Promise to indicate it is an asynchronous operation. The ControlFlow will wait for such promises to be resolved before marking the task as completed.

Tasks and each callback registered on a webdriver.promise.Deferred will be run in their own ControlFlow frame. Any tasks scheduled within a frame will have priority over previously scheduled tasks. Furthermore, if any of the tasks in the frame fails, the remainder of the tasks in that frame will be discarded and the failure will be propagated to the user through the callback/task's promised result.

Each time a ControlFlow empties its task queue, it will fire an webdriver.promise.ControlFlow.EventType.IDLE event. Conversely, whenever the flow terminates due to an unhandled error, it will remove all remaining tasks in its queue and fire an webdriver.promise.ControlFlow.EventType.UNCAUGHT_EXCEPTION event. If there are no listeners registered with the flow, the error will be rethrown to the global error handler.

Parameters:
{webdriver.promise.ControlFlow.Timer=} opt_timer: The timer object to use. Should only be set for testing.

Field Detail

<static> webdriver.promise.ControlFlow.defaultTimer

The default timer object, which uses the global timer functions.

<static> webdriver.promise.ControlFlow.EVENT_LOOP_FREQUENCY

How often, in milliseconds, the event loop should run.

<static> webdriver.promise.ControlFlow.EventType

Events that may be emitted by an webdriver.promise.ControlFlow.

timer

The timer used by this instance.

Method Detail

{!(Error|goog.testing.JsUnitException)} annotateError(e)

Appends a summary of this instance's recent task history to the given error's stack trace. This function will also ensure the error's stack trace is in canonical form.

Parameters:
{!(Error|goog.testing.JsUnitException)} e: The error to annotate.

Returns:: {!(Error|goog.testing.JsUnitException)} The annotated error.

{!webdriver.promise.Promise} await(promise)

Schedules a task that will wait for another promise to resolve. The resolved promise's value will be returned as the task result.

Parameters:
{!webdriver.promise.Promise} promise: The promise to wait on.

Returns:: {!webdriver.promise.Promise} A promise that will resolve when the task has completed.

clearHistory()

Clears this instance's task history.

{!webdriver.promise.Promise} execute(fn, opt_description)

Schedules a task for execution. If there is nothing currently in the queue, the task will be executed in the next turn of the event loop.

Parameters:
{!Function} fn: The function to call to start the task. If the function returns a webdriver.promise.Promise, this instance will wait for it to be resolved before starting the next task.
{string=} opt_description: A description of the task.

Returns:: {!webdriver.promise.Promise} A promise that will be resolved with the result of the action.

{!Array.} getHistory()

Returns a summary of the recent task activity for this instance. This includes the most recently completed task, as well as any parent tasks. In the returned summary, the task at index N is considered a sub-task of the task at index N+1.

Returns:: {!Array.} A summary of this instance's recent task activity.

{string} getSchedule()

Returns:: {string} The scheduled tasks still pending with this instance.

reset()

Resets this instance, clearing its queue and removing all event listeners.

{!webdriver.promise.Promise} timeout(ms, opt_description)

Inserts a {@code setTimeout} into the command queue. This is equivalent to a thread sleep in a synchronous programming language.

Parameters:
{number} ms: The timeout delay, in milliseconds.
{string=} opt_description: A description to accompany the timeout.

Returns:: {!webdriver.promise.Promise} A promise that will be resolved with the result of the action.

{!webdriver.promise.Promise} wait(condition, timeout, opt_message)

Schedules a task that shall wait for a condition to hold. Each condition function may return any value, but it will always be evaluated as a boolean.

Condition functions may schedule sub-tasks with this instance, however, their execution time will be factored into whether a wait has timed out.

In the event a condition returns a Promise, the polling loop will wait for it to be resolved before evaluating whether the condition has been satisfied. The resolution time for a promise is factored into whether a wait has timed out.

If the condition function throws, or returns a rejected promise, the wait task will fail.

Parameters:
{!Function} condition: The condition function to poll.
{number} timeout: How long to wait, in milliseconds, for the condition to hold before timing out.
{string=} opt_message: An optional error message to include if the wait times out; defaults to the empty string.

Returns:: {!webdriver.promise.Promise} A promise that will be resolved when the condition has been satisified. The promise shall be rejected if the wait times out waiting for the condition.

API Reference for selenium-webdriver v2.39.0

Classes

Class webdriver.promise.ControlFlow