Item instance null?

thkrebs · January 1, 2016, 5:42pm

I am trying to access an item named Openhab_Start in a rule triggered by a timer. The item seems not to be initialized. However, I verified with a REST call that it is initialized.
This drives me nuts. I have no glue what is wrong here:

Stripped down rule:

import org.joda.time.*
import org.openhab.core.library.types.*

rule "Check Sensor liveliness"
when
    Time cron "* 0/2 * ? * *"
then
    logInfo("sensor alivecheck", "in rule") 
    logInfo("Openhab start", Openhab_Start.state)

    )
end

Item value retrieved with REST API call:
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>DateTimeItemOpenhab_Start2016-01-01T17:42:
25http://localhost:8080/rest/items/Openhab_Start

Log:

2016-01-01 18:30:20.006 [INFO ] [org.openhab.model.script.sensor alivecheck        ] - in rule
2016-01-01 18:30:20.032 [ERROR] [.openhab.model.rule.internal.engine.ExecuteRuleJob] - Error during the execution of rule Check Sensor liveliness
java.lang.IllegalStateException: Could not invoke method: org.openhab.model.script.actions.LogAction.logInfo(java.lang.String,java.lang.String,java.lang.Object[]) on instance: null

Udo_Hartmann · January 1, 2016, 6:47pm

You can’t log a state, you have to use a string for logging:
logInfo("Openhab start ", Openhab_Start.state.toString)
should do the trick.

thkrebs · January 1, 2016, 7:29pm

Hi Udo,

thanks for the fast reply. The log statement was just to get a handle on the overal problems I am facing here.
What I eventually would like to achieve is to check for all my sensors when they have been updated the last time and for the items which are not initialized I would use the time openhab was started as the basis for the offset.

But anyway, I changed the statement as you suggested and get now a different exception.

The exception changed…

2016-01-01 20:20:20.006 [INFO ] [org.openhab.model.script.sensor alivecheck        ] - in rule
2016-01-01 20:20:20.012 [INFO ] [org.openhab.model.script.Openhab start            ] - 2016-01-01T17:42:25
2016-01-01 20:20:20.044 [ERROR] [.openhab.model.rule.internal.engine.ExecuteRuleJob] - Error during the execution of rule Check Sensor liveliness
java.lang.IllegalStateException: Ambiguous methods [protected java.lang.Object org.eclipse.xtext.xbase.interpreter.impl.XbaseInterpreter._evaluateAssignment(org.eclipse.xtext.xbase.XAssignment,org.eclipse.xtext.xbase.interpreter.IEvaluationContext,org.eclipse.xtext.util.CancelIndicator), protected java.lang.Object org.eclipse.xtext.xbase.interpreter.impl.XbaseInterpreter._evaluateBlockExpression(org.eclipse.xtext.xbase.XBlockExpression,org.eclipse.xtext.xbase.interpreter.IEvaluationContext,org.eclipse.xtext.util.CancelIndicator), protected java.lang.Object org.eclipse.xtext.xbase.interpreter.impl.XbaseInterpreter._evaluateBooleanLiteral(org.eclipse.xtext.xbase.XBooleanLiteral,org.eclipse.xtext.xbase.interpreter.IEvaluationContext,org.eclipse.xtext.util.CancelIndicator), protected java.lang.Object org.eclipse.xtext.xbase.interpreter.impl.XbaseInterpreter._evaluateCastedExpression(org.eclipse.xtext.xbase.XCastedExpression,org.eclipse.xtext.xbase.interpreter.IEvaluationContext,org.eclipse.xtext.util.CancelIndicator), protected java.lang.Object org.eclipse.xtext.xbase.interpreter.impl.XbaseInterpreter._evaluateClosure(org.eclipse.xtext.xbase.XClosure,org.eclipse.xtext.xbase.interpreter.IEvaluationContext,org.eclipse.xtext.util.CancelIndicator), protected java.lang.Object org.eclipse.xtext.xbase.interpreter.impl.XbaseInterpreter._evaluateConstructorCall(org.eclipse.xtext.xbase.XConstructorCall,org.eclipse.xtext.xbase.interpreter.IEvaluationContext,org.eclipse.xtext.util.CancelIndicator), protected org.eclipse.xtext.xbase.interpreter.IEvaluationResult org.eclipse.xtext.xbase.interpreter.impl.XbaseInterpreter._evaluateDoWhileExpression(org.eclipse.xtext.xbase.XDoWhileExpression,org.eclipse.xtext.xbase.interpreter.IEvaluationContext,org.eclipse.xtext.util.CancelIndicator), protected java.lang.Object org.eclipse.xtext.xbase.interpreter.impl.XbaseInterpreter._evaluateForLoopExpression(org.eclipse.xtext.xbase.XForLoopExpression,org.eclipse.xtext.xbase.interpreter.IEvaluationContext,org.eclipse.xtext.util.CancelIndicator), protected java.lang.Object org.eclipse.xtext.xbase.interpreter.impl.XbaseInterpreter._evaluateIfExpression(org.eclipse.xtext.xbase.XIfExpression,org.eclipse.xtext.xbase.interpreter.IEvaluationContext,org.eclipse.xtext.util.CancelIndicator), protected java.lang.Object org.eclipse.xtext.xbase.interpreter.impl.XbaseInterpreter._evaluateInstanceOf(org.eclipse.xtext.xbase.XInstanceOfExpression,org.eclipse.xtext.xbase.interpreter.IEvaluationContext,org.eclipse.xtext.util.CancelIndicator), protected java.lang.Object org.eclipse.xtext.xbase.interpreter.impl.XbaseInterpreter._evaluateMemberFeatureCall(org.eclipse.xtext.xbase.XMemberFeatureCall,org.eclipse.xtext.xbase.interpreter.IEvaluationContext,org.eclipse.xtext.util.CancelIndicator), protected java.lang.Object org.eclipse.xtext.xbase.interpreter.impl.XbaseInterpreter._evaluateNullLiteral(org.eclipse.xtext.xbase.XNullLiteral,org.eclipse.xtext.xbase.interpreter.IEvaluationContext,org.eclipse.xtext.util.CancelIndicator), protected java.lang.Object org.eclipse.xtext.xbase.interpreter.impl.XbaseInterpreter._evaluateNumberLiteral(org.eclipse.xtext.xbase.XNumberLiteral,org.eclipse.xtext.xbase.interpreter.IEvaluationContext,org.eclipse.xtext.util.CancelIndicator), protected java.lang.Object org.eclipse.xtext.xbase.interpreter.impl.XbaseInterpreter._evaluateReturnExpression(org.eclipse.xtext.xbase.XReturnExpression,org.eclipse.xtext.xbase.interpreter.IEvaluationContext,org.eclipse.xtext.util.CancelIndicator), protected java.lang.Object org.eclipse.xtext.xbase.interpreter.impl.XbaseInterpreter._evaluateStringLiteral(org.eclipse.xtext.xbase.XStringLiteral,org.eclipse.xtext.xbase.interpreter.IEvaluationContext,org.eclipse.xtext.util.CancelIndicator), protected java.lang.Object org.eclipse.xtext.xbase.interpreter.impl.XbaseInterpreter._evaluateSwitchExpression(org.eclipse.xtext.xbase.XSwitchExpression,org.eclipse.xtext.xbase.interpreter.IEvaluationContext,org.eclipse.xtext.util.CancelIndicator), protected java.lang.Object org.eclipse.xtext.xbase.interpreter.impl.XbaseInterpreter._evaluateThrowExpression(org.eclipse.xtext.xbase.XThrowExpression,org.eclipse.xtext.xbase.interpreter.IEvaluationContext,org.eclipse.xtext.util.CancelIndicator), protected java.lang.Object org.eclipse.xtext.xbase.interpreter.impl.XbaseInterpreter._evaluateTryCatchFinallyExpression(org.eclipse.xtext.xbase.XTryCatchFinallyExpression,org.eclipse.xtext.xbase.interpreter.IEvaluationContext,org.eclipse.xtext.util.CancelIndicator), protected java.lang.Object org.eclipse.xtext.xbase.interpreter.impl.XbaseInterpreter._evaluateTypeLiteral(org.eclipse.xtext.xbase.XTypeLiteral,org.eclipse.xtext.xbase.interpreter.IEvaluationContext,org.eclipse.xtext.util.CancelIndicator), protected java.lang.Object org.eclipse.xtext.xbase.interpreter.impl.XbaseInterpreter._evaluateVariableDeclaration(org.eclipse.xtext.xbase.XVariableDeclaration,org.eclipse.xtext.xbase.interpreter.IEvaluationContext,org.eclipse.xtext.util.CancelIndicator), protected java.lang.Object org.eclipse.xtext.xbase.interpreter.impl.XbaseInterpreter._evaluateWhileExpression(org.eclipse.xtext.xbase.XWhileExpression,org.eclipse.xtext.xbase.interpreter.IEvaluationContext,org.eclipse.xtext.util.CancelIndicator)] for params [null, org.eclipse.xtext.xbase.interpreter.impl.DefaultEvaluationContext@8614f5, org.eclipse.xtext.util.CancelIndicator$1@17445a2]
	at org.eclipse.xtext.util.PolymorphicDispatcher.handleAmbigousMethods(PolymorphicDispatcher.java:308) ~[na:na]
	at org.eclipse.xtext.util.PolymorphicDispatcher.invoke(PolymorphicDispatcher.java:283) ~[na:na]
	at org.eclipse.xtext.xbase.interpreter.impl.XbaseInterpreter.internalEvaluate(XbaseInterpreter.java:218) ~[na:na]
	at org.eclipse.xtext.xbase.interpreter.impl.XbaseInterpreter.evaluate(XbaseInterpreter.java:204) ~[na:na]
	at org.eclipse.xtext.xbase.interpreter.impl.ClosureInvocationHandler.doInvoke(ClosureInvocationHandler.java:46) ~[na:na]
	at org.eclipse.xtext.xbase.interpreter.impl.AbstractClosureInvocationHandler.invoke(AbstractClosureInvocationHandler.java:28) ~[na:na]
	at com.sun.proxy.$Proxy86.apply(Unknown Source) ~[na:na]
	at org.eclipse.xtext.xbase.lib.IterableExtensions.forEach(IterableExtensions.java:395) ~[na:na]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0]
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0]
	at java.lang.reflect.Method.invoke(Method.java:483) ~[na:1.8.0]
	at org.eclipse.xtext.xbase.interpreter.impl.XbaseInterpreter.invokeOperation(XbaseInterpreter.java:729) ~[na:na]
	at org.eclipse.xtext.xbase.interpreter.impl.XbaseInterpreter._featureCallOperation(XbaseInterpreter.java:713) ~[na:na]
	at sun.reflect.GeneratedMethodAccessor56.invoke(Unknown Source) ~[na:na]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0]
	at java.lang.reflect.Method.invoke(Method.java:483) ~[na:1.8.0]
	at org.eclipse.xtext.util.PolymorphicDispatcher.invoke(PolymorphicDispatcher.java:291) ~[na:na]
	at org.openhab.model.script.interpreter.ScriptInterpreter.internalFeatureCallDispatch(ScriptInterpreter.java:69) ~[na:na]
	at org.eclipse.xtext.xbase.interpreter.impl.XbaseInterpreter._evaluateMemberFeatureCall(XbaseInterpreter.java:549) ~[na:na]
	at sun.reflect.GeneratedMethodAccessor50.invoke(Unknown Source) ~[na:na]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0]
	at java.lang.reflect.Method.invoke(Method.java:483) ~[na:1.8.0]
	at org.eclipse.xtext.util.PolymorphicDispatcher.invoke(PolymorphicDispatcher.java:291) ~[na:na]
	at org.eclipse.xtext.xbase.interpreter.impl.XbaseInterpreter.internalEvaluate(XbaseInterpreter.java:218) ~[na:na]
	at org.eclipse.xtext.xbase.interpreter.impl.XbaseInterpreter._evaluateBlockExpression(XbaseInterpreter.java:321) ~[na:na]
	at sun.reflect.GeneratedMethodAccessor57.invoke(Unknown Source) ~[na:na]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0]
	at java.lang.reflect.Method.invoke(Method.java:483) ~[na:1.8.0]
	at org.eclipse.xtext.util.PolymorphicDispatcher.invoke(PolymorphicDispatcher.java:291) ~[na:na]
	at org.eclipse.xtext.xbase.interpreter.impl.XbaseInterpreter.internalEvaluate(XbaseInterpreter.java:218) ~[na:na]
	at org.eclipse.xtext.xbase.interpreter.impl.XbaseInterpreter.evaluate(XbaseInterpreter.java:204) ~[na:na]
	at org.openhab.model.script.internal.engine.ScriptImpl.execute(ScriptImpl.java:59) ~[na:na]
	at org.openhab.model.rule.internal.engine.ExecuteRuleJob.execute(ExecuteRuleJob.java:55) ~[na:na]
	at org.quartz.core.JobRunShell.run(JobRunShell.java:213) [quartz-all-2.1.7.jar:na

rlkoshak · January 1, 2016, 7:41pm

I suspect that Openhab_Start is undefined. Are you certain Openhab_Start has been set when this rule executes?

thkrebs · January 1, 2016, 8:07pm

I suspect that Openhab_Start is undefined. Are you certain Openhab_Start has been set when this rule executes?

I am sure the item is defined. At least that is what the REST call shows, see my initial post.

Udo_Hartmann · January 1, 2016, 9:16pm

Ah. there is a closing bracket before end which causes the errors.You can see the expected Output from the logInfos at Line 1 and 2:2016-01-01 20:20:20.006 [INFO ] [org.openhab.model.script.sensor alivecheck ] - in rule 2016-01-01 20:20:20.012 [INFO ] [org.openhab.model.script.Openhab start ] - 2016-01-01T17:42:25

thkrebs · January 1, 2016, 9:39pm

Uhh shi… Thanks a lot for pointing that out. I am really sorry, having bothered you with a syntax error.
Lesson learnt: Do edit rules and config files only in OpenHab Designer.

Udo_Hartmann · January 3, 2016, 12:04am

Never mind I’ve also done many typos so far…