[jboss-jira] [JBoss JIRA] Commented: (JBRULES-2608) Variable Persistence Overwrites NULL Values over Persisted Values

[Mauricio Salatino (JIRA)]

    [ https://jira.jboss.org/browse/JBRULES-2608?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12543845#action_12543845 ] 

Mauricio Salatino commented on JBRULES-2608:
--------------------------------------------

In the scenario that you mention, if you remove the out mapping from the second work item it should work.
Why this is a problem?
PROBLEM: "Third workitem needs to pick up the same list that was PERSISTED and is not able to do so" 

In the second work item you receive the list as in parameter, do whatever you want and then you want to complete your work item use those results to call the manager.completeWorkItem().

WorkItemHandler has like channels from ins and outs and it store what it's going in on the database. But it's your responsibility to mangle and store all the intermediate information that it's being handled.
Remember workitemhandler are outside the scope of the framework and it's not the framework responsibility to handle all the information inside them.
Just my two cents.

> Variable Persistence Overwrites NULL Values over Persisted Values
> -----------------------------------------------------------------
>
>                 Key: JBRULES-2608
>                 URL: https://jira.jboss.org/browse/JBRULES-2608
>             Project: Drools
>          Issue Type: Bug
>      Security Level: Public(Everyone can see) 
>          Components: All
>    Affects Versions: 5.1.0.FINAL
>         Environment: N/A
>            Reporter: Anatoly Polinsky
>            Assignee: Mauricio Salatino
>         Attachments: difference-between-first-and-second-work-item.png, drools-vp-jira.zip, passing-list-process-test.png, passing-list-process.png
>
>   Original Estimate: 4 hours
>  Remaining Estimate: 4 hours
>
> Drools Flow
> =========
>    For non-String variables (Serializ..ble, Entities, etc..), Drools overwrites NULLs when a (JPA) process is resumed ( a workitem is completed ).
>    1. Here is a use case: a List ( ArrayList ) is passed to the process in start as a parameter 
>    2. First work item sees ( maps in ) the List, and can work with it inside the work item handler
>    3. First work item does not complete: process goes to sleep.
>    4. When the session is reloaded, the first work item is completed
>    5. All the persisted variables ( including the "list" ) are restored
>    6. Second work item is taking in the list ( it maps in )
>    7. However at this point it is NULL
>    It seems that when the context is closed, after resolving variables, the following (WorkItemNodeInstance):
>             VariableScopeInstance variableScopeInstance = ( VariableScopeInstance )
>                     resolveContextInstance( VariableScope.VARIABLE_SCOPE, mapping.getValue() );
>     does no longer have the restored variables, and rather NULLs, since internally variables are compared with a "result map" that was passed to the previous work item.
>     This means that persisted variables are restored internally, but then overwritten internally by NULLs.
> /Anatoly

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