How to use a Side Effect in Java

To use a Side Effect in Java, set the sideEffect() function in your Workflow Execution and return the nondeterministic code.

  int random = Workflow.sideEffect(Integer.class, () -> random.nextInt(100));
  if random < 50 {
         ....
  } else {
         ....
  }

Here's another example that uses sideEffect().

// implementation of the @WorkflowMethod
public void execute() {
    int randomInt = Workflow.sideEffect( int.class, () -> {
        Random random = new SecureRandom();
        return random.nextInt();
    });

    String userHome = Workflow.sideEffect(String.class, () -> System.getenv("USER_HOME"));

    if(randomInt % 2 == 0) {
        // ...
    } else {
        // ...
    }
}

Java also provides a deterministic method to generate random numbers or random UUIDs.

To generate random numbers in a deterministic method, use newRandom()

// implementation of the @WorkflowMethod
public void execute() {
    int randomInt = Workflow.newRandom().nextInt();
    // ...
}

To generate a random UUID in a deterministic method, use randomUUID().

// implementation of the @WorkflowMethod
public void execute() {
    String randomUUID = Workflow.randomUUID().toString();
    // ...
}