[jboss-jira] [JBoss JIRA] Commented: (JBRULES-1403) Control-Flow Statement into "action nodes" (RULEFLOW)

[Kris Verlaenen (JIRA)]

    [ http://jira.jboss.com/jira/browse/JBRULES-1403?page=comments#action_12409036 ] 
            
Kris Verlaenen commented on JBRULES-1403:
-----------------------------------------

We discourage the use of control flow statements like if () in MVEL, especially inside rule consequences (to force the user into making rules more declarative). You can override this default by setting the MVEL language level (which is actually a static property in MVEL) to 5 by changing the "drools.dialect.mvel.langLevel" configuration property, for example by using a configuration file or by using this code to create your PackageBuilder:

PackageBuilderConfiguration conf = new PackageBuilderConfiguration();
((MVELDialectConfiguration) conf.getDialectConfiguration("mvel")).setLangLevel(5);
PackageBuilder builder = new PackageBuilder(conf);
...

You can also simply use the Java dialect, which supports all normal Java control flow constructs.

> Control-Flow Statement into "action nodes" (RULEFLOW)
> -----------------------------------------------------
>
>                 Key: JBRULES-1403
>                 URL: http://jira.jboss.com/jira/browse/JBRULES-1403
>             Project: JBoss Drools
>          Issue Type: Feature Request
>      Security Level: Public(Everyone can see) 
>          Components: Eclipse IDE
>    Affects Versions: 4.0.3
>         Environment: Eclipse Europa 3.3.1.1
>            Reporter: Massimiliano Magistri
>         Assigned To: Kris Verlaenen
>             Fix For: 5.0.0-M1
>
>         Attachments: action.jpg
>
>
> I tried to add the following (stupid) statement into the action node "textual editor":
> if (true) int i=0;
> and I got back an exception as follows:
> org.mvel.PropertyAccessException: unable to resolve property: if ( true )
> 	at org.mvel.optimizers.impl.refl.ReflectiveAccessorOptimizer.compileGetChain(ReflectiveAccessorOptimizer.java:291)
> 	at org.mvel.optimizers.impl.refl.ReflectiveAccessorOptimizer.optimizeAccessor(ReflectiveAccessorOptimizer.java:107)
> 	at org.mvel.ASTNode.getReducedValueAccelerated(ASTNode.java:185)
> 	at org.mvel.MVELRuntime.execute(MVELRuntime.java:88)
> 	at org.mvel.CompiledExpression.getValue(CompiledExpression.java:108)
> 	at org.mvel.MVEL.executeExpression(MVEL.java:230)
> 	at org.drools.ruleflow.instance.impl.ActionNodeInstanceImpl.trigger(ActionNodeInstanceImpl.java:93)
> 	at org.drools.ruleflow.instance.impl.StartNodeInstanceImpl.triggerCompleted(StartNodeInstanceImpl.java:38)
> 	at org.drools.ruleflow.instance.impl.StartNodeInstanceImpl.trigger(StartNodeInstanceImpl.java:30)
> 	at org.drools.ruleflow.instance.impl.RuleFlowProcessInstanceImpl.start(RuleFlowProcessInstanceImpl.java:172)
> 	at org.drools.common.AbstractWorkingMemory.startProcess(AbstractWorkingMemory.java:1409)
> 	at mytest.TestRF.testScritturaContractRF(TestRF.java:95)
> 	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
> 	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
> 	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
> 	at java.lang.reflect.Method.invoke(Unknown Source)
> 	at junit.framework.TestCase.runTest(TestCase.java:154)
> 	at junit.framework.TestCase.runBare(TestCase.java:127)
> 	at junit.framework.TestResult$1.protect(TestResult.java:106)
> 	at junit.framework.TestResult.runProtected(TestResult.java:124)
> 	at junit.framework.TestResult.run(TestResult.java:109)
> 	at junit.framework.TestCase.run(TestCase.java:118)
> 	at junit.framework.TestSuite.runTest(TestSuite.java:208)
> 	at junit.framework.TestSuite.run(TestSuite.java:203)
> 	at org.eclipse.jdt.internal.junit.runner.junit3.JUnit3TestReference.run(JUnit3TestReference.java:130)
> 	at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
> 	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:460)
> 	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:673)
> 	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:386)
> 	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:196)
> Caused by: java.lang.NullPointerException
> 	at org.mvel.optimizers.impl.refl.ReflectiveAccessorOptimizer.getMethod(ReflectiveAccessorOptimizer.java:519)
> 	at org.mvel.optimizers.impl.refl.ReflectiveAccessorOptimizer.compileGetChain(ReflectiveAccessorOptimizer.java:257)
> 	... 29 more
> Is it possible to add "flow control" statements into the action ruleflow nodes?

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