How to deal with Type Safety problem

Flowable Engine
1

The following code calls variable() method to set up the variable in the process instance, and the data type is “Object”.

import org.flowable.engine.RuntimeService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Service
public class OrderProcessService implements OrderProcessInterface
{
    @Autowired
    private RuntimeService runtimeService;

    @Override
    public void triggerOrderProcess(final OrderDetails body)
    {
        final OrderProcessData orderProcessData = new OrderProcessData();
        orderProcessData.setHasPostpaidEntries(body.isHasPostpaidEntries());

        runtimeService.createProcessInstanceBuilder()
            .processDefinitionKey("simpleProcess")
            .variable("orderId", body.getOrderId())
            .variable("orderProcessData", orderProcessData)
            .start();
    }

}

The problem is, when I try to retrieve the value using the following code snippet of the task (Delegate class), I have to cast the Object back to String. Is there an elegant way, such as generic type, to deal with type safety problem? (viz. to avoid ClassCastException)

    @Override
    public void execute(final DelegateExecution execution)
    {
        logger.info("Started {}", LocalDateTime.now());

        final String orderId = (String) execution.getVariable("orderId");
2

The VariableScope interface, which DelegateExecution extends, has a generic method
<T> T getVariable(String variableName, Class<T> variableClass);
to retrieve a workflow variable in a more strongly typed way. Of course this doesn’t alleviate the potential runtime errors if the type of variable stored in the workflow doesn’t match what the code is expecting.

3

Indeed… it’s better than nothing though. Thanks for the answer.