traits_futures.i_event_loop_helper module

Interface for toolkit-specific event loop helper class.

class traits_futures.i_event_loop_helper.IEventLoopHelper

Bases: abc.ABC

Interface for toolkit-specific event loop helper class.

An IEventLoopHelper instance provides a way to run the event loop programmatically until a given condition occurs. Its primary use is in testing.

abstract dispose()

Dispose of any resources used by this object.

This method is not thread-safe. It should always be called on the event loop’s thread.

abstract init()

Prepare the event loop for use.

This method is not thread-safe. It should always be called on the event loop’s thread.

abstract run_until(object, trait, condition, timeout)

Run event loop until a given condition occurs, or timeout.

The condition is re-evaluated, with the object as argument, every time the trait changes.

This method is not thread-safe. It should always be called on the event loop’s thread.

Parameters

• object (traits.has_traits.HasTraits) – Object whose trait we monitor.

• trait (str) – Name of the trait to monitor for changes.

• condition – Single-argument callable, returning a boolean. This will be called with object as the only input.

• timeout (float) – Number of seconds to allow before timing out with an exception.

Raises

RuntimeError – If timeout is reached, regardless of whether the condition is true or not at that point.

abstract setattr_soon(obj, name, value)

Arrange for an attribute to be set once the event loop is running.

In typical usage, obj will be a HasTraits instance and name will be the name of a trait on obj.

This method is not thread-safe. It should always be called on the event loop’s thread.

Parameters

• obj (object) – Object to set the given attribute on.

• name (str) – Name of the attribute to set; typically this is a traited attribute.

• value (object) – Value to set the attribute to.