Waitset Use Cases
[Programming How-To's]

Using wait-sets and conditions. More...

Setting up a wait-set

• Create a wait-set

    WaitSet waitset = new WaitSet();
  

• Attach conditions

    Condition cond1 = ...;
    Condition cond2 = entity.get_statuscondition();
    Condition cond3 = reader.create_readcondition(
        SampleStateKind.NOT_READ_SAMPLE_STATE,
        ViewStateKind.ANY_VIEW_STATE,
        InstanceStateKind.ANY_INSTANCE_STATE);
    Condition cond4 = new GuardCondition();
    Condition cond5 = ...;                                                   
  
    waitset.attach_condition(cond1);
    waitset.attach_condition(cond2);
    waitset.attach_condition(cond3);
    waitset.attach_condition(cond4);
    waitset.attach_condition(cond5);
  

Waiting for condition(s) to trigger

• Set up a wait-set

• Wait for a condition to trigger or timeout, whichever occurs first

    Duration_t timeout = new Duration_t(0, 1000000); // 1ms
  
    ConditionSeq active_conditions = new ConditionSeq(); // list of active conditions
  
    boolean is_cond1_triggered = false;
    boolean is_cond2_triggered = false;
  
    try {
        waitset.wait(active_conditions, timeout);
  
        // check if "cond1" or "cond2" are triggered:
        for (int i = 0; i < active_conditions.size(); ++i) {
            if (active_conditions.get(i) == cond1) {
                System.out.println("Cond1 was triggered!");
                is_cond1_triggered = true;
            }
            if (active_conditions.get(i) == cond2) {
                System.out.println("Cond2 was triggered!");
                is_cond2_triggered = true;
            }
        }
  
        if (is_cond1_triggered) {
            // ... do something because "cond1" was triggered ...
        }
  
        if (is_cond2_triggered) {
            // ... do something because "cond2" was triggered ...
        }
    } catch (RETCODE_TIMEOUT timed_out) {
        // timeout!
        System.out.println(
            "Wait timed out!! None of the conditions was triggered.");
    } catch (RETCODE_ERROR ex) {
        // ... check for cause of failure
         throw ex;
    }
  

Tearing down a wait-set

• Delete the wait-set

    waitset.delete();     
    waitset = null;
    // let the wait set be garbage collected