com.uber.cadence.worker

Class Worker

java.lang.Object

com.uber.cadence.worker.Worker

All Implemented Interfaces:

Suspendable

public final class Worker
extends java.lang.Object
implements Suspendable

Hosts activity and workflow implementations. Uses long poll to receive activity and decision tasks and processes them in a correspondent thread pool.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	Worker.Factory Maintains worker creation and lifecycle.
static class	Worker.FactoryOptions

Method Summary

Modifier and Type	Method and Description
<R> void	addWorkflowImplementationFactory(java.lang.Class<R> workflowInterface, Functions.Func<R> factory) Configures a factory to use when an instance of a workflow implementation is created.
java.lang.String	getTaskList()
boolean	isSuspended()
void	registerActivitiesImplementations(java.lang.Object... activityImplementations) Register activity implementation objects with a worker.
void	registerWorkflowImplementationTypes(java.lang.Class<?>... workflowImplementationClasses) Register workflow implementation classes with a worker.
void	registerWorkflowImplementationTypes(WorkflowImplementationOptions options, java.lang.Class<?>... workflowImplementationClasses) Register workflow implementation classes with a worker.
void	replayWorkflowExecution(java.lang.String jsonSerializedHistory) This is an utility method to replay a workflow execution using this particular instance of a worker.
void	replayWorkflowExecution(WorkflowExecutionHistory history) This is an utility method to replay a workflow execution using this particular instance of a worker.
void	resumePolling() Allow new poll requests.
void	suspendPolling() Do not make new poll requests.
java.lang.String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Method Detail

registerWorkflowImplementationTypes

public void registerWorkflowImplementationTypes(java.lang.Class<?>... workflowImplementationClasses)

Register workflow implementation classes with a worker. Overwrites previously registered types. A workflow implementation class must implement at least one interface with a method annotated with WorkflowMethod. That method becomes a workflow type that this worker supports.

Implementations that share a worker must implement different interfaces as a workflow type is identified by the workflow interface, not by the implementation.

The reason for registration accepting workflow class, but not the workflow instance is that workflows are stateful and a new instance is created for each workflow execution.

registerWorkflowImplementationTypes

public void registerWorkflowImplementationTypes(WorkflowImplementationOptions options,
                                                java.lang.Class<?>... workflowImplementationClasses)

Register workflow implementation classes with a worker. Overwrites previously registered types. A workflow implementation class must implement at least one interface with a method annotated with WorkflowMethod. That method becomes a workflow type that this worker supports.

Implementations that share a worker must implement different interfaces as a workflow type is identified by the workflow interface, not by the implementation.

The reason for registration accepting workflow class, but not the workflow instance is that workflows are stateful and a new instance is created for each workflow execution.

addWorkflowImplementationFactory

public <R> void addWorkflowImplementationFactory(java.lang.Class<R> workflowInterface,
                                                 Functions.Func<R> factory)

Configures a factory to use when an instance of a workflow implementation is created. The only valid use for this method is unit testing, specifically to instantiate mocks that implement child workflows. An example of mocking a child workflow:

   worker.addWorkflowImplementationFactory(ChildWorkflow.class, () -> {
     ChildWorkflow child = mock(ChildWorkflow.class);
     when(child.workflow(anyString(), anyString())).thenReturn("result1");
     return child;
   });
 

Unless mocking a workflow execution use registerWorkflowImplementationTypes(Class[]).

Type Parameters:

R - type of the workflow object to create.

Parameters:

workflowInterface - Workflow interface that this factory implements

factory - factory that when called creates a new instance of the workflow implementation object.

registerActivitiesImplementations

public void registerActivitiesImplementations(java.lang.Object... activityImplementations)

Register activity implementation objects with a worker. Overwrites previously registered objects. As activities are reentrant and stateless only one instance per activity type is registered.

Implementations that share a worker must implement different interfaces as an activity type is identified by the activity interface, not by the implementation.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

replayWorkflowExecution

public void replayWorkflowExecution(WorkflowExecutionHistory history)
                             throws java.lang.Exception

This is an utility method to replay a workflow execution using this particular instance of a worker. This method is useful to troubleshoot workflows by running them in a debugger. To work the workflow implementation type must be registered with this worker. There is no need to call start() to be able to call this method.

Parameters:

history - workflow execution history to replay

Throws:

java.lang.Exception - if replay failed for any reason

replayWorkflowExecution

public void replayWorkflowExecution(java.lang.String jsonSerializedHistory)
                             throws java.lang.Exception

This is an utility method to replay a workflow execution using this particular instance of a worker. This method is useful to troubleshoot workflows by running them in a debugger. To work the workflow implementation type must be registered with this worker. There is no need to call start() to be able to call this method.

Parameters:

jsonSerializedHistory - workflow execution history in JSON format to replay

Throws:

java.lang.Exception - if replay failed for any reason

getTaskList

public java.lang.String getTaskList()

suspendPolling

public void suspendPolling()

Description copied from interface: Suspendable

Do not make new poll requests. Outstanding long polls still can return tasks after this method was called.

Specified by:

suspendPolling in interface Suspendable

resumePolling

public void resumePolling()

Description copied from interface: Suspendable

Allow new poll requests.

Specified by:

resumePolling in interface Suspendable

isSuspended

public boolean isSuspended()

Specified by:

isSuspended in interface Suspendable