Start A Parallel Method On A Running Workflow

A running workflow instance can have multiple methods running in parallel. When it's the case, those executions share the internal properties of this workflow instance.

This can be used to trigger new actions or to access or update the workflow properties.

// create stub of a running HelloWorkflow workflow
HelloWorkflow w = 
    client.getWorkflowById(HelloWorkflow.class, id);

// running `HelloWorkflow::method` of the targeted workflow without waiting for the result
Deferred<Boolean> deferred = client.dispatch(w::method, ...);

// running `HelloWorkflow::method` on the targeted workflow and wait for its boolean result
Boolean result = w.method(...);

// create stub of a running HelloWorkflow workflow
val w : HelloWorkflow =
    client.getWorkflowById(HelloWorkflow::class.java, id)

// running `HelloWorkflow::method` of the targeted workflow without waiting for the result
val deferred : Deferred<Boolean> = client.dispatch(w::method, ...)

// running `HelloWorkflow::method` on the targeted workflow and wait for its boolean result
val result = w.method(...)

Due to some Java syntax constraints, if the return type of the method used is void, we need to use dispatchVoid function instead of dispatch.

Another way to target some running workflows is to used the getWorkflowByTag function that take a workflow interface and a tag as parameter. For example:

// create the stub of running HelloWorkflow workflows with tag
HelloWorkflow w =
    getWorkflowByTag(HelloWorkflow.class, tag);

// running `HelloWorkflow::method` of the targeted workflows without waiting for the boolean result
Deferred<Boolean> deferred = client.dispatch(w::method, ...);

// create the stub of running workflows with tag
val w : HelloWorkflow =
    getWorkflowByTag(HelloWorkflow::class.java, tag)

// running `HelloWorkflow::method` of the targeted workflow without waiting for the boolean result
val deferred : Deferred<Boolean> = client.dispatch(w::method, ...)

In the example above, the "HelloWorkflow::method" will run on all workflows having the provided tag.

When targeting workflows by tag, it's not possible to retrieve deferred.id or to do deferred.await(), as the deferred can target multiple instances.