Hook: Define New Capability

Requirement

A new type of capability is needed.

Method of Adaptation

Add Feature

Level of Support

Open Ended

HotSpot

User management

Participants

AbstractCapability, NewCapability , NewCapabilityOn , NewCapabilityOff

Changes

1. subclass NewCapability of AbstractCapability.
2. subclass NewCapabilityOn of NewCapability.
3. subclass NewCapabilityOff of NewCapability.
4. NewCapabilityOn.isGranted implements AbstractCapability.isGranted returning true .
5. NewCapabilityOn.getToggled implements AbstractCapability.getToggled returning instance of NewCapabilityOff.
6. NewCapabilityOff.isGranted implements AbstractCapability.isGranted returning false .
7. NewCapabilityOff.getToggled implements AbstractCapability.getToggled returning instance of NewCapabilityOn.
8. new abstract method NewCapability.execute .
9. NewCapabilityOn.execute implements NewCapability.execute .
10. NewCapabilityOff.execute implements NewCapability.execute .

Constraints

• The new capability must be immutable, i.e. once create the state of an object of this class cannot be changed.
• The execute method executes the code that is guarded by the Capability. NewCapabilityOn.execute will perform the actual code, while NewCapabilityOff.execute may present an error message or otherwise deny the right to execute the code.

Comments

• A special case are capabilities that guard actions . These can be implemented using users.ActionCapability .