Guide to adaptor classes¶

The following sections describe the different adaptor subclasses that exist for use in your workflows, the use cases that motivate them, and how to configure them.

Adaptor¶

The base Adaptor class is abstract and cannot be instantiated on its own but does have configuration parameters that are common to all adaptors and must be provided:

id: this is an integer identifying the adaptor. Although currently unused, all adaptor JSON should provide a unique, non-zero value as it may be used in the future to reference adaptors during configuration.
type: this is the fully-qualified class name of the adaptor class that should be created.
from: an integer used to identify the task which should be observed and used to configure another.
to: an integer used to identify the task which should be configured when the “from” task has changed into a completable or completed state.

Example¶

{
  "id": 1,
  "type": "smtk::task::Adaptor",
  "from": 1,
  "to": 2
}

ResourceAndRole¶

The ResourceAndRole adaptor exists to pass information from GatherResources to FillOutAttributes, possibly passing this information “through” Groups that have these tasks as children. When configured, only attribute resources chosen by the user will be examined for validity.

The ResourceAndRole adaptor accepts two additional JSON configuration entries beyond the base Adaptor class:

from-tag: this is a string used only when the “from” task is a Group. It specifies a key in the Group’s interal configuration object from which to fetch data to apply to the destination task. The default value is an empty string.
to-tag: this is a string used only when the “to” task is a Group. It specifies a key in the Group’s interal configuration object to which to write data that will be applied to the destination task. The default value is an empty string.

The Group from- and to-tag strings exist because a Group task may need to aggregate state from multiple child tasks or configure multiple child tasks separately. By providing the key, authors can control which child tasks share or do not share configuration information. If the default empty string is used, then all tasks will share the same configuration information.

Example¶

{
  "id": 1,
  "type": "smtk::task::adaptor::ResourceAndRole",
  "from": 1, /* must be a GatherResources or Group task */
  "to": 2,   /* must be a FillOutAttributes or Group task */
  "to-tag": "foo" /* if "to" is a Group, "foo" is a key for resource+role data. */
}