cts-examples.md

CTS - examples

Example A

In order to obtain the service, wire into your Spring eco-system the interface ClusterTasksService. It is a singleton, so the best practice would be to (auto)wire it as a private member of any of your services/components using it. Detailed info on service's API available here.

Next, you'd like to drop you actual logic for some task processing. To do that, you'll need to implement one of the task processor's base classes and expose them as a Spring beans. Your processor typically would look like this:

@Component
public class HeavyRecalcAsyncCTP extends ClusterTasksProcessorSimple {
	private static List<Long> numbers;      //  caution, statics are not thread/scope safe
	private List<String> strings;           //  caution, CTPs are singletons, so this is not thread/scope safe either

	protected HeavyRecalcAsyncCTP() {
		super(ClusterTasksDataProviderType.DB, 3);
	}

	@Override
	public void processTask(ClusterTask task) {
		//  TODO: write your logic here
	}
}

• Best practice would be to have all your logic encapsulated within the processTask method and any helper methods that are called from it, while all of the data sets from both, an original task and of intermediate calculations/transformation/processing - rolling around as local variables/method parameters (pay attention to the thread/scope safety remarks in the example above).

To see your processor taking the task, is to enqueue it:

@Autowired
private ClusterTasksService clusterTasksService;
...

private void doRecalcOfNewContent(String newContentSerialized) {
	//  prepare task
	ClusterTask task = TaskBuilders.simpleTask()
			.setDelayByMillis(5000L)
			.setBody(newContentSerialized)
			.build();

	//  enqueue task to the DB storage (the only available as of now) and to the correct processor
	ClusterTaskPersistenceResult[] enqueueResults = clusterTasksService.enqueueTasks(
		ClusterTasksDataProviderType.DB,
		"HeavyRecalcAsyncCTP",
		task);

	//  you may inspect results of enqueue and process/log/retry any abnormalities
	...
}

• Obviously, tasks should be submitted to the specific processor. To achieve that, you need to specify processor's type (second parameter). By default processor's type is its simple class name, but you can change it overriding getType method in your processor's implementation.