Class TargetBase<TDerived, TInput>

An abstract dataflow worker with one Input port, which can be used to create a dataflow target.

When starting a worker, the library calls RunAsync() during the worker Running phase. A derived class must override this abstract method, and call methods on the Input port to consume data rows from the upstream worker.

Note that the worker Running phase also includes additional places where logic can optionally be inserted via callbacks, to e.g. customize the initialization, cleanup, and error handling of existing workers. This is mostly used when customizing workers that are not designed to be derived from (i.e. without a "Base" suffix). See Worker Life-cycle for details.

Use TargetBase<TDerived, TInput, TError> instead if an ErrorOutput port is needed. Also see the TargetBase example.

Note: The input port uses the Default policy. Consider whether this is appropriate, or should be changed, see BufferingMode for further details.

Inheritance
Object
WorkerParent
WorkerBase
WorkerBase<TDerived>
TargetBase<TDerived, TInput>
Implements
Inherited Members
Namespace: actionETL
Assembly: actionETL.dll
Syntax
public abstract class TargetBase<TDerived, TInput> : WorkerBase<TDerived>, IDisposeOnFinished where TDerived : TargetBase<TDerived, TInput> where TInput : class
Type Parameters
Name Description
TDerived

The type of the derived worker. Class definition example:

public class MyTarget<TInput>
    : TargetBase<MyTarget<TInput>,TInput>
    where TInput : class
{ 
    // ...
}
TInput

The type of each Input row.

Constructors

TargetBase(DownstreamFactory<TInput>, String)

Initializes a new instance of the TargetBase<TDerived, TInput> dataflow worker with one Input port.

Declaration
protected TargetBase(in DownstreamFactory<TInput> downstreamFactory, string workerName)
Parameters
Type Name Description
DownstreamFactory<TInput> downstreamFactory

The downstream factory, which specifies the parent worker and (optionally) the upstream port to link the "first" input port of this dataflow worker to.

Get it from Link when the upstream port is known ahead of time (which is usually the case). Otherwise get it from GetDownstreamFactory<TInput>(), and link the transform or target explicitly using LinkTo(InputPort<TOutput>) or LinkFrom(OutputPortBase<TInput>).

String workerName

Name of the worker.

Set to a prefix plus a trailing "/" (e.g. "MyPrefix-/") to generate a unique name from the prefix plus an increasing number starting at 1.

While less useful, set to null, whitespace or "/" to generate a unique name from the worker type plus an increasing number starting at 1.

The name cannot otherwise contain "/", and cannot start with double underscore "__".

Exceptions
Type Condition
ArgumentException

workerName:

  • Workers with the same parent must have unique names.
  • Worker and worker system names cannot contain '/' or start with double underscore '__'.
ArgumentNullException

workerParent - All workers must have a parent. The top level workers have the worker system as parent.
InvalidOperationException
  • Cannot add child worker to parent which has completed. Are you adding it to the correct parent?
  • Cannot add worker to parent, since its children have been started. Are you adding it to the correct parent?

Properties

Input

Gets the input port for receiving rows from an upstream worker.

Declaration
public InputPort<TInput> Input { get; }
Property Value
Type Description
InputPort<TInput>

Implements