| « PreviousNext » | |
   | Did this page help you? Yes | No | Tell us about it... |
Workflow and Activity Type Registration
Amazon SWF requires activity and workflow types to be registered before they can be used. The
framework automatically registers the workflows and activities in the implementations you add
to the worker. The framework looks for types that implement workflows and activities and
registers them with Amazon SWF. By default, the framework uses the interface definitions to infer
registration options for workflow and activity types. All workflow interfaces are required to
have either the @WorkflowRegistrationOptions annotation or the
@SkipRegistration annotation. The workflow worker registers all workflow types
it is configured with that have the @WorkflowRegistrationOptions annotation.
Similarly, each activity method is required to be annotated with either the
@ActivityRegistrationOptions annotation or the @SkipRegistration
annotation or one of these annotations must be present on the @Activities
interface. The activity worker registers all activity types that it is configured with that an
@ActivityRegistrationOptions annotation applies to. The registration is
performed automatically when you start one of the workers. Workflow and activity types that
have the @SkipRegistration annotation are not registered.
@ActivityRegistrationOptions, and @SkipRegistration annotations
have override semantics and the most specific one is applied to an activity type.
Note that Amazon SWF does not allow you to re-register or modify the type after it has been registered once. The framework will try to register all types, but if the type is already registered it will not be re-registered and no error will be reported. If you need to modify registered settings, you should register a new version of the type. You can also override registered settings when starting a new execution or calling an activity using the generated clients.
The registration requires a type name and some other registration options. The default implementation determines these as follows:
Workflow Type Name and Version
The framework determines the name of the workflow type from the workflow interface. The
form of the default workflow type name is
{prefix}{name}. The
{prefix} is set to the name of the @Workflow
interface followed by a '.' and the {name} is set to the name of
the @Execute method. The default name of the workflow type in the above example
is: MyWorkflow.startMyWF. You can override the default name using the name
parameter of the @Execute method. The default name of the workflow type in the
above example is: startMyWF. The name must not be an empty string. Note that
when you override the name using @Execute, the framework will not automatically
prepend a prefix to it. You are free to use your own naming scheme.
The workflow version is specified using the version parameter of the
@Workflow annotation. There is no default for the version and it must be
explicitly specified. Version is a free form string and you are free to use your own
versioning scheme.
Signal Name
The name of the signal can be specified using the name parameter of the @Signal annotation.
If not specified, it is defaulted to the name of the signal method.
Activity Type Name and Version
The framework determines the name of the activity type from the activities interface.
The form of the default activity type name is {prefix}{name}. The {prefix} is set to the name of the @Activities interface followed
by a '.' and the {name} is set to the method name. The
default {prefix} can be overridden in the @Activities annotation on the
activities interface. You can also specify the activity type name using the
@Activity annotation on the activity method. Note that when you override the
name using @Activity, the framework will not automatically prepend a prefix to
it. You are free to user your own naming scheme.
The activity version is specified using the version parameter of the
@Activities annotation. This version is used as the default for all
activities defined in the interface and can be overridden on a per-activity basis using the
@Activity annotation.
Default Task List
The default task list can be configured using the
@WorkflowRegistrationOptions and @ActivityRegistrationOptions
annotations and setting the defaultTaskList parameter. By default, it is set to
USE_WORKER_TASK_LIST. This is a special value that instructs the
framework to use the task list that is configured on the worker object that is used to
register the activity or workflow type. You can also choose to not register a default task
list by setting the default task list to NO_DEFAULT_TASK_LIST using
these annotations. This can be used in cases where you want to require that the task list be
specified at run time. If no default task list has been registered, then you must specify
the task list when starting the workflow or calling the activity method using the
StartWorkflowOptions and ActivitySchedulingOptions parameters on
the respective method overload of the generated client.
Other Registration Options
All workflow and activity type registration options that are allowed by the Amazon SWF API can be specified through the framework.
For a complete list of workflow type registration options, see the sections on @Workflow, @Execute, @WorkflowRegistrationOptions, and @Signal annotations.
For a complete list of activity type registration options, see the sections on @Activity, @Activities, and @ActivityRegistrationOptions annotations.
If you want to have complete control over type registration, see Worker Extensibility.
