OSID - osid.Operable Service Interface Definition

Interface	osid.Operable
Implemented By	`osid.course.Course`
	`osid.course.ActivityUnit`
	`osid.assessment.authoring.AssessmentPart`
	`osid.OsidRule`
	`osid.OsidGovernator`
	`osid.repository.Composition`
	`osid.journaling.Branch`
	`osid.offering.CanonicalUnit`
	`osid.configuration.Value`
	`osid.course.program.Program`
	`osid.mapping.path.Obstacle`
	`osid.control.Controller`
Description	`Operable` is used to indicate an `OsidObject` performs operations. The active status indicates if the `Operable` is on or off. The active status is determined from the operational status and the enabling rules. The operational status indicates the Operable is functioning. This status is not set administratively but instead refelects suitable conditions for operation. Operables may be administratively turned on of off through the enabled and disabled administrative overrides. If there are no related `OsidOperator` rules, then `isEnabled()` should be set to `true` and `isDisabled()` set to `false` for the `Operable` to be on and `isEnabled()` set to `false` and `isDisabled()` set to true for the `Operable` to be `off`. `isEnabled()` and `isDisabled()` cannot both be `true`. If there are related `OsidOperator` rules, the active status of at least one `OsidOperator` results in a `true` value for `isOperational()`. This active status can be overridden by setting `isDisabled()` to `true`. If there are no active `OsidOperator` rules, `isOperational()` is false resulting in an `off` `Operable` unless `isEnabled()` is `true`. For the active status to be completely determined by the `OsidOperators`, both `isEnabled()` and `isDisabled()` should be `false` where the `isActive()` status is completely driven from `isOperational()`.
Method	isActive
Description	Tests if this operable is active. `isActive()` is `true` if `isOperational()` is `true` and `isDisabled()` is `false`, or `isEnabled()` is `true`. If an `Operable` is also a `Temporal`, `isEffective()` must also be `true`.
Return	`boolean`	`true` if this operable is active, `false` if it is inactive
Compliance	`mandatory`	This method must be implemented.
Method	isEnabled
Description	Tests if this operable is administravely enabled. Administratively enabling overrides any applied `OsidOperator`. If this method returns `true` then `isDisabled()` must return `false`. Applied `OsidEnablers` effect `isOperational()`. This method is an administrative override.
Return	`boolean`	`true` if this operable is enabled, `false` if the active status is determined by other rules
Compliance	`mandatory`	This method must be implemented.
Method	isDisabled
Description	Tests if this operable is administravely disabled. Administratively disabling overrides any `OsidOperator`. If this method returns `true` then `isEnabled()` must return `false`.
Return	`boolean`	`true` if this operable is disabled, `false` if the active status is determined by other rules
Compliance	`mandatory`	This method must be implemented.
Method	isOperational
Description	Tests if this `Operable` is operational. This `Operable` is operational if any of the applied `OsidOperators` are `true`.
Return	`boolean`	`true` if this operable is operational, `false` otherwise
Compliance	`mandatory`	This method must be implemented.