Workflow interface

Workflow encapsulates the orchestration of activities and child workflows. It can also answer synchronous queries and receive external events (also known as signals).

Samples

Runnable workflow-interface samples:

Sample	Description	Code
File processing	Interface with signal and query methods	FileProcessingWorkflow.java
Signal and query methods	Workflow interfaces that define signal or query methods	HelloSignal.java · HelloQuery.java
Separate interface and implementation	Workflow interface and implementation in separate files	calculation

A workflow must define an interface class. All of its methods must have one of the following annotations:

@WorkflowMethod indicates an entry point to a workflow. It contains parameters such as timeouts and a task_list. Required parameters (such as executionStartToCloseTimeoutSeconds) that are not specified through the annotation must be provided at runtime.
@SignalMethod indicates a method that reacts to external signals. It must have a void return type.
@QueryMethod indicates a method that reacts to synchronous query requests.

You can have more than one method with the same annotation (except @WorkflowMethod). For example:

public interface FileProcessingWorkflow {

    @WorkflowMethod(executionStartToCloseTimeoutSeconds = 10, taskList = "file-processing")
    String processFile(Arguments args);

    @QueryMethod(name="history")
    List<String> getHistory();

    @QueryMethod(name="status")
    String getStatus();

    @SignalMethod
    void retryNow();

    @SignalMethod
    void abandon();
}

We recommended that you use a single value type argument for workflow methods. In this way, adding new arguments as fields to the value type is a backwards-compatible change.

Samples​

Samples