Zeebe Client Api ideas

Api.java

public interface ZeebeClient
{
    ZeebeTopicClient topic(String topicName);

    Map<String, PartitionInfo> listTopics();
}

public interface ZeebeTopicClient
{
    Future<TaskEvent> createTask(CreateTaskCommand cmd);

    Future<TaskEvent> completeTask(CompleteTaskCommand cmd);
    
    Future<WorkflowInstanceEnvent> createWorkflowInstance(CompleteTaskCommand cmd);

    TopicSubscriptionBuilder<Event> newEventSubscription();
        
    // 
    
    PollableTaskSubscriptionBuilder newPollableTaskSubscription();    
    
    PollableEventSubscriptionBuilder newPollableEventSubscription();

    <T extends Event> newEventSubscription(Class<T> type);
    
    ...
}

DeployWorkflowInstance.java

ZeebeClient client = ...;
ZeebeTopicClient orderTopic = client.topic("order-processing");

try
{
    Future<WorkflowInstanceEvent> evt = orderTopic.deployWorkflow(new DeployWorkflowCommand("foo.bpmn").replaceOldVersions());
}
catch (CommandFailedException e)
{
    // handle error
}

ListTopics.java

ZeebeClient client = null;

Map<String, PartitionInfo> partitions = client.listTopics();

PartitionInfo partitionInfo = partitions.get("order-processing");
Node leader = partitionInfo.getLeader();
List<Node> leader = partitionInfo.getFollowers();

StartWorkflowInstance.java

ZeebeClient client = ...;
ZeebeTopicClient orderTopic = client.topic("order-processing");

// start wf instance sync

try
{
    Future<WorkflowInstanceEvent> evt = orderTopic.createWorkflowInstance(new StartWorkflowInstanceCommand("orderProcess")
       .payload(...));
}
catch (CommandFailedException e)
{
    // handle error
}

 // -----------------------------------------------------------------------

// start wf instance async

final Future<WorkflowInstanceEvent> evt = orderTopic.sendAsync(new StartWorkflowInstanceCommand("orderProcess")
    .payload(...));

try
{
    evt.join();
}
catch (CommandFailedException e)
{
    // handle error
}

TaskWorkerAsync.java

ZeebeClient client = ...;
ZeebeTopicClient orderTopic = client.topic("order-processing");

// async task handler
orderTopic.newTaskSubscription("fraudCheck")
    // ...
    .handler(new TaskHandler()
    {
        @Override
        public void handle(TaskEvent taskEvent)
        {
            // store in database
            database.store(taskEvent.getKey(), taskEvent.toJson());
        }
    })
    .open();

// later
String taskEventJson = database.load(taskKey);
TaskEvent taskEvent = TaskEvent.fromJson(taskEvent);

try {
    topicClient.completeTask(new CompleteTaskCommand(taskEvent).payload(...));
}
catch (CommandFailedException e)
{
    // handle error
}

TaskWorkerSync.java

ZeebeClient client = ...;
ZeebeTopicClient orderTopic = client.topic("order-processing");

orderTopic.newTaskSubscription("fraudCheck")
    // ...
    .handler(new TaskHandler()
    {
        @Override
        public void handle(TaskEvent taskEvent)
        {
            // do work ...

            try
            {
                topicClient.completeTask(new CompleteTaskCommand(taskEvent).payload(...));
            }
            catch (CommandFailedException e)
            {
                // handle error
            }
        }
    })
    .open();