com.uber.cadence.worker

Class Worker

java.lang.Object

com.uber.cadence.worker.Worker

public final class Worker
extends java.lang.Object

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	isClosed()
boolean	isStarted()
<R> R	queryWorkflowExecution(WorkflowExecution execution, java.lang.String queryType, java.lang.Class<R> returnType, java.lang.Object... args) This is an utility method to query a workflow execution using this particular instance of a worker.
<R> R	queryWorkflowExecution(WorkflowExecution execution, java.lang.String queryType, java.lang.Class<R> resultClass, java.lang.reflect.Type resultType, java.lang.Object... args) This is an utility method to query a workflow execution using this particular instance of a worker.
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.
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.

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.

isStarted

public boolean isStarted()

isClosed

public boolean isClosed()

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

queryWorkflowExecution

public <R> R queryWorkflowExecution(WorkflowExecution execution,
                                    java.lang.String queryType,
                                    java.lang.Class<R> returnType,
                                    java.lang.Object... args)
                             throws java.lang.Exception

This is an utility method to query a workflow execution using this particular instance of a worker. It gets a history from a Cadence service, replays a workflow code and then runs the query. 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. In most cases using WorkflowClient to query workflows is preferable, as it doesn't require workflow implementation code to be available. There is no need to call start() to be able to call this method.

Type Parameters:

R - type of the query result

Parameters:

execution - workflow execution to replay and then query locally

queryType - query type to execute

returnType - return type of the query result

args - query arguments

Returns:

query result

Throws:

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

queryWorkflowExecution

public <R> R queryWorkflowExecution(WorkflowExecution execution,
                                    java.lang.String queryType,
                                    java.lang.Class<R> resultClass,
                                    java.lang.reflect.Type resultType,
                                    java.lang.Object... args)
                             throws java.lang.Exception

This is an utility method to query a workflow execution using this particular instance of a worker. It gets a history from a Cadence service, replays a workflow code and then runs the query. 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. In most cases using WorkflowClient to query workflows is preferable, as it doesn't require workflow implementation code to be available. There is no need to call start() to be able to call this method.

Type Parameters:

R - type of the query result

Parameters:

execution - workflow execution to replay and then query locally

queryType - query type to execute

resultClass - return class of the query result

resultType - return type of the query result. Useful when resultClass is a generic type.

args - query arguments

Returns:

query result

Throws:

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

getTaskList

public java.lang.String getTaskList()