Cannot assign a value in null context. and HashMap - what is wrong?

Setup, Configuration and Use Scripts & Rules
1

I have following code:

Variable definition:

var Map<String,Timer> WtrTimers = newHashMap( 
	"WtrValveFront_StartTimer" -> null,
	"WtrValveFront_StopTimer"  -> null,
	"WtrValveBack_StartTimer" -> null,
	"WtrValveBack_StopTimer"  -> null,
	"WtrValveLine_StartTimer" -> null,
	"WtrValveLine_StopTimer"  -> null,	
	"Wtr_StopTimer"			  -> null
 )

In rule:

 if(WtrTimers == null) {
		logError("FILE", "Wtr_starting_stoping: WtrTimer was not initialized")
		WtrTimers = newHashMap( 
		"WtrValveFront_StartTimer" -> null,
		"WtrValveFront_StopTimer"  -> null,
		"WtrValveBack_StartTimer" -> null,
		"WtrValveBack_StopTimer"  -> null,
		"WtrValveLine_StartTimer" -> null,
		"WtrValveLine_StopTimer"  -> null,
		"Wtr_StopTimer"			  -> null
		)
		logInfo( "FILE", "Wtr_starting_stoping: After reinitializing WtrTimers[" + WtrTimers + "]")
	}

ā€¦

and in the log Iā€™ve got:

2018-06-19 05:00:00.711 [ERROR] [.eclipse.smarthome.model.script.FILE] - Wtr_starting_stoping: WtrTimer was not initialized
2018-06-19 05:00:00.728 [ERROR] [.script.engine.ScriptExecutionThread] - Rule ā€˜Wtr_starting_stopingā€™: An error occurred during the script execution: Cannot assign a value in null context.

As you see WtrTimers == null returns null but ā€œWtrTimers = newHashMap(ā€¦ā€ raise error but why? It looks like normal initialization.

Michal Szymanski

2

Why bother initializing the Map in the first place? If the key you are searching for isnā€™t there it returns null anyway.

Just create the hashmap and skip all this initialization stuff.

Along those lines, I donā€™t think it will let you initialize the map with null because I think it actually removes that key value pair from the map when you set the value to null anyway.

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