Class RepeatRowsSource<TOutput>

A dataflow worker that generates an arbitrary number of rows, often used for testing, debugging etc. The caller provides template rows as an IEnumerable, or as rows specified in the constructor, which are by default repeatedly cloned (using CreateDeepCloneFunc()) in a round-robin fashion, to generate and pass the output rows to a downstream worker. This way, only the new cloned rows with distinct references are sent downstream.

Note: When cloning rows (the default), all mapped column data types must support multi-copy. To only select some columns for copying, use ColumnMapperCommandAction.

Alternatively, you can set SendTemplateRows to true to instead repeatedly send the template rows as is downstream. Note that if true and TotalNumberOfRows is larger than the number of template rows, the same row object reference will be sent multiple times, which is strongly discouraged unless the row type is immutable, or you can guarantee that no downstream worker will modify the rows. See Row Ownership for details.

By default, all (readable and writable) columns in the template rows are included in the cloning. Use ColumnMapperCommandAction to only clone selected columns.

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

The type of each Output row.

Constructors

RepeatRowsSource(WorkerParent, String, Func<Boolean>, Int64, TOutput[])

Initializes a new instance of the RepeatRowsSource<TOutput> dataflow worker that generates an arbitrary number of rows by cloning provided template rows, and passes them to a downstream worker.

Declaration
public RepeatRowsSource(WorkerParent workerParent, string workerName, Func<bool> isStartableFunc, long totalNumberOfRows, params TOutput[] rows)
Parameters
Type Name Description
WorkerParent workerParent

The parent worker or worker system that the new child worker will be added to. Cannot be null.
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 "__".

Func<Boolean> isStartableFunc

Function to calculate the worker start constraint; it should return true for startable and false for not startable. Defaults to startable if null.
Int64 totalNumberOfRows

The total number of rows to generate.
TOutput[] rows

The template rows to generate output rows from.
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 '__'.
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?

RepeatRowsSource(WorkerParent, String, Func<Boolean>, Int64, IEnumerable<TOutput>)

Initializes a new instance of the RepeatRowsSource<TOutput> dataflow worker that generates an arbitrary number of rows by cloning provided template rows, and passes them to a downstream worker.

Declaration
public RepeatRowsSource(WorkerParent workerParent, string workerName, Func<bool> isStartableFunc, long totalNumberOfRows, IEnumerable<TOutput> rows)
Parameters
Type Name Description
WorkerParent workerParent

The parent worker or worker system that the new child worker will be added to. Cannot be null.
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 "__".

Func<Boolean> isStartableFunc

Function to calculate the worker start constraint; it should return true for startable and false for not startable. Defaults to startable if null.
Int64 totalNumberOfRows

The total number of rows to generate.
IEnumerable<TOutput> rows

The enumerable with template rows to generate output rows from.
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 '__'.
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?

RepeatRowsSource(WorkerParent, String, Int64, TOutput[])

Initializes a new instance of the RepeatRowsSource<TOutput> dataflow worker that generates an arbitrary number of rows by cloning provided template rows, and passes them to a downstream worker.

Declaration
public RepeatRowsSource(WorkerParent workerParent, string workerName, long totalNumberOfRows, params TOutput[] rows)
Parameters
Type Name Description
WorkerParent workerParent

The parent worker or worker system that the new child worker will be added to. Cannot be null.
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 "__".

Int64 totalNumberOfRows

The total number of rows to generate.
TOutput[] rows

The template rows to generate output rows from.
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 '__'.
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?

RepeatRowsSource(WorkerParent, String, Int64, IEnumerable<TOutput>)

Initializes a new instance of the RepeatRowsSource<TOutput> dataflow worker that generates an arbitrary number of rows by cloning provided template rows, and passes them to a downstream worker.

Declaration
public RepeatRowsSource(WorkerParent workerParent, string workerName, long totalNumberOfRows, IEnumerable<TOutput> rows)
Parameters
Type Name Description
WorkerParent workerParent

The parent worker or worker system that the new child worker will be added to. Cannot be null.
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 "__".

Int64 totalNumberOfRows

The total number of rows to generate.
IEnumerable<TOutput> rows

The enumerable with template rows to generate output rows from.
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 '__'.
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

ColumnMapperCommandAction

Gets or sets the column mapping. Defaults to mapping all columns, i.e. cb => cb.AutoName(). Set this property to only map selected columns, see Dataflow Column Mapping for details. Columns that are not mapped will retain their default value in the output rows, which can be used to avoid copying SingleShallow columns (which would fail). Cannot be set after the worker has started running.

Column name matching is ordinal case insensitive, but a case sensitive match takes precedence over a case insensitive match.

Note: This property is thread-safe.

Declaration
public Action<IColumnMapperCommand> ColumnMapperCommandAction { get; set; }
Property Value
Type Description
Action<IColumnMapperCommand>
Exceptions
Type Condition
InvalidOperationException

Cannot set the value after the worker has started running.

Output

Gets the output port for sending rows to the downstream worker.

Declaration
public OutputPort<TOutput> Output { get; }
Property Value
Type Description
OutputPort<TOutput>

Rows

Sets an enumerable that contains or produces the template rows. This overwrites any template rows specified in the constructor. Cannot be set after the worker has started running.

Note: This property is thread-safe.

Declaration
public IEnumerable<TOutput> Rows { set; }
Property Value
Type Description
IEnumerable<TOutput>
Exceptions
Type Condition
InvalidOperationException

Cannot set the value after the worker has started running.

SendTemplateRows

Gets or sets whether to repeatedly send the template rows as is (true), or repeatedly clone them and only send cloned rows (false, the default).

Note that if true and TotalNumberOfRows is larger than the number of template rows, the same row object reference will be sent multiple times, which is strongly discouraged unless the row type is immutable, or you can guarantee that no downstream worker will modify the rows. See Row Ownership for details.

Cannot be set after the worker has started running.

Note: This property is thread-safe.

Declaration
public bool SendTemplateRows { get; set; }
Property Value
Type Description
Boolean
Exceptions
Type Condition
InvalidOperationException

Cannot set the value after the worker has started running.

TotalNumberOfRows

Get or sets the total number of rows to generate. Cannot be set after the worker has started running.

Note: This property is thread-safe.

Declaration
public long TotalNumberOfRows { get; set; }
Property Value
Type Description
Int64
Exceptions
Type Condition
InvalidOperationException

Cannot set the value after the worker has started running.

Methods

RunAsync()

This method can be overridden to add custom functionality to the derived worker that runs before and after the row processing. In this case, the base class base.RunAsync() must be called for the worker to function correctly.

Typically, this worker is used without overriding this method.

Declaration
protected override async Task<OutcomeStatus> RunAsync()
Returns
Type Description
Task<OutcomeStatus>

A Task describing the success or failure of the worker. An asynchronous async implementation would e.g. return OutcomeStatus.Succeeded on success, while a synchronous implementation would return OutcomeStatus.SucceededTask.
Overrides

Implements