Capability urgentAlert

Devices & Integrations Capability Type Suggestions
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I hope adding more analogies doesn’t sidetrack the Topic, but this first major Capability addition seems to be stimulating conversation. I do cover some of this in my Guidelines Topic in this Category, and will be adding more.

And most of what I just wrote below was just better stated by JD as I was writing.
Ref:

So … I used “mouse” (mouse drivers that implement the interface/capability “mouse”) as my analogy, whereas JD used “printer drivers”. Same intention, same message.
Thanks, @JDRoberts!!!

  1. Capabilities should (really, must) be the only way a SmartApp (or external application) can access a physical device for input and/or output. The Device Type handler “implements” the interface to the Capabilities, but should not expose anything that is not defined in the Capability.

  2. The interface model is common to all HAL (hardware abstraction layer) architectures. On a PC, a “mouse” is an interface with certain capabilities. The applications which use a mouse don’t care what brand it is, or even if it is a trackball or some other weird implementation of mouse. The applications just know it has buttons and motion and perhaps a scroll-wheel.

  3. There is no direct relationship between a mouse and the application. The mouse and the Pointer (cursor) are not a part of the same interface: They are, in fact, two distinct interfaces. The pointer, however, is a very useful interface that responds to applications that use the mouse, though other non-mouse applications can access it’s interface and move it around, change its appearance, etc.

  4. Capability.alarm is like the pointer – it is a display (output) capability (as is capability.indicator).

  5. Capability.urgentAlert is like a mouse – it is an input capability (as is capability.contactSensor).

  6. Some Capabilities are input and output (Capability.switch is an “output” capability when you use Commands to turn the switch on/off; it is an “input” capability when it reports its current state (or state change) as on/off, and that state change could be initiated from a Command or from a physical action (pressing the button or wall switch or another remote).