Cancel Running Workflows

The cancellation of a workflow stops its execution and delete its state.

We can cancel running workflows by using a stub that target them by id:

HelloWorldWorkflow w = 
    client.getWorkflowById(HelloWorldWorkflow.class, id);

client.cancel(w);

val w : HelloWorldWorkflow = 
    client.getWorkflowById(HelloWorldWorkflow::class.java, id)

client.cancel(w)

or by tag:

HelloWorldWorkflow w = 
    client.getWorkflowByTag(HelloWorldWorkflow.class, "foo");

client.cancel(w);

val w : HelloWorldWorkflow = 
    client.getWorkflowByTag(HelloWorldWorkflow::class.java, "foo")

client.cancel(w)

The direct cancellation of a child workflow will trigger a CanceledWorkflowException in the parent workflow if waiting for its completion.

The cancel method waits for the adhoc message to be sent to Pulsar. If we prefer to not wait for this message to be sent, we can use the cancelAsync method.