Get and Dispose RuntimeEngine for Task Queries?

[vutnal]

According to jBPM6.0 user guide:

At request

•     get RuntimeEngine from RuntimeManager using proper context instance dedicated to strategy of RuntimeManager
•     get KieSession and/or TaskService from RuntimeEngine
•     perform operations on KieSession and/or TaskService such as startProcess, completeTask, etc
•     once done with processing dispose RuntimeEngine using RuntimeManager.disposeRuntimeEngine method

Typically, in an application user queries tasks more often than actually starting a process instance. So in such cases, is it a good idea to get RuntimeEngine everytime to use TaskService and dispose after that?

Following code snippet never uses KieSession. Is it necessary to dispose the engine at the end at every request? And will the taskService be still available after I dispose the runtimeEngine?

RuntimeManager manager; // Per process instance strategy - at application startup

public List<TaskSummary> listAllTasksForUser(String username, string locale){
    
    RuntimeEngine engine = manager.getRuntimeEngine(EmptyContext.get());
    TaskService taskService = engine.getTaskService();
    
    List<TaskSummary> taskList = taskService.getTasksAssignedAsPotentialOwner(username,locale);
    taskList.addAll(taskService.getTasksOwned(username ,locale));
    
    manager.disposeRuntimeEngine(engine);    
    
    return taskList;
}

[swiderski.maciej]

whenever you create RuntimeEngine you need to dispose it once you're done working on it. Regardless if you use KieSession or TaskService as both will be created and initialized.

Alternatively for query related operations on task service you can create instance of TaskService that will be "standalone" mode meaning not connected to any KieSession. That instance can be used for read only operations like query. To create an instance of it you can either use CDI (if you use CDI) or use HumanTaskServiceFactory to get configurator object that allows you to configure TaskService instance according to your needs.

HTH

[vutnal]

Thanks Maciej. This was really helpful.

Can you please provide me some example to use HumanTaskServiceFactory to configure Task Services (Preferably Mina HT Service similar to one used in jbpm5.4)?

[swiderski.maciej]

in jBPM 6 TaskService is used as local task service by default so it's just a matter of creating the instance of it. Here you can find an example how to do it.

HTH

[vutnal]

Thanks Maciej. will explore more on this.