sendCommandIfDifferent fails with Dimmer and Number Items when using String commands

[rkoshak]

Expected Behavior

If the Dimmer or Number is 0, calling sendCommandIfDifferent("0") or calling sendCommandIfDifferent("0.0") should both suppress the command.

Current Behavior

If sending 0 or 0.0 as a command the command is suppressed. If sending the value as a String however, the command is not suppressed.

Possible Solution

My first thought was to make _toOpenhabPrimitiveType smarter but I don't think it has enough information there to do so.

So I think sendCommandIfDifferent needs to see if it can parse the string to a number and if so compare the parsed value to the numericValue.

I'm not sure how to handle Quantity. If I send "0" to a Number:Dimensionless that's 0 % the command isn't suppressed. If I send "0 %" the command is suppressed. Sending 0 the command is also suppressed. So for consistency I'd say we need to parse the value to a Quantity if the Item has a a QuantiyType too but what if the string is without units? Do we assume the same units as the quantityValue? It gets rather complicated, but handlable.

I can supply a PR but need advice on whether to address the Quantity issue as well.

Steps to Reproduce (for Bugs)

1. Create a test Number and/or Dimmer Item
2. initialize it with the value 0
3. from a script call items.TestItem.sendCommandIfDifferent("0") and observe the command was send in any of the usual ways (e.g. events.log)

Context

In my Presence Simulation rule template I was only sending the string version of the value retrieved from persistence as a command to the Item. However, because it's a String, it litters the logs with commands which should not have occurred because the Item is already in that state.

Your Environment

• openHAB version used (check Main UI -> About): 4.3 release
• openhab-js version used (run console.log('openhab-js ' + utils.OPENHAB_JS_VERSION) from a JS script): 5.8.1
• Operating System and version (e.g. desktop or mobile, Windows 10, Raspbian Buster, ...): Official OH Docker Image (debian)