fix creating processEngine with instance of ProcessEngineConfigurationIm...

[kotslon]

I get an error trying to create engine bean using an instance of org.activiti.engine.impl.cfg.StandaloneProcessEngineConfiguration, which is a descendant of org.activiti.engine.impl.cfg.ProcessEngineConfigurationImpl, but has no transaction manager unlike org.activiti.spring.SpringProcessEngineConfiguration.

An error occurs in org.activiti.spring.ProcessEngineFactoryBean when it tries to cast configuration bean to org.activiti.spring.SpringProcessEngineConfiguration:

Caused by: java.lang.ClassCastException: org.activiti.engine.impl.cfg.StandaloneProcessEngineConfiguration cannot be cast to org.activiti.spring.SpringProcessEngineConfiguration
at org.activiti.spring.ProcessEngineFactoryBean.configureExternallyManagedTransactions(ProcessEngineFactoryBean.java:72)

The same code works on previous versions of Activiti bacause of the appropriate type checking:

public class ProcessEngineFactoryBean implements FactoryBean<ProcessEngine>, DisposableBean, ApplicationContextAware {
    // ...
    protected void initializeTransactionExternallyManaged() {
        if (processEngineConfiguration instanceof SpringProcessEngineConfiguration) { // remark: any config can be injected, so we cannot have SpringConfiguration as member
            SpringProcessEngineConfiguration engineConfiguration = (SpringProcessEngineConfiguration) processEngineConfiguration;
            if (engineConfiguration.getTransactionManager() != null) {
                processEngineConfiguration.setTransactionsExternallyManaged(true);
            }
        }
    }
    // ...
}

I hope, that check was not deleted intentionally, but removed accidently during refactoring here when initializeTransactionExternallyManaged() was renamed to configureExternallyManagedTransactions().

So, I want it to be there, to be able to use any ProcessEngineConfigurationImpl (StandaloneProcessEngineConfiguration in my case).

[jbarrez]

Related: http://forums.activiti.org/content/javalangclasscastexception-standaloneinmemprocessengineconfiguration-cannot-be-cast

[jbarrez]

Valid point. That shouldn't have gone through.

Thanks for fixing it!

[ftanil]

Does activiti releases minor versions or do we need to (officially) wait for the 5.18.0 for this fix? (By the way, I know I can get the sources from here and build myself, but that's not an option to use that for our current build process)