FeatureWriter

Categories

Format Specific

Workflows

Writes features to any FME-supported writer.

The FeatureWriter can be used instead of a conventional FME writer. Using the FeatureWriter allows post-processing of writer results, such as outputting a report based on the success or failure of the writer.

Configuration

Input Ports

Any number of input ports can be created either by connecting to the Connect Input port or by editing the transformer properties and manually adding new inputs. Each input port corresponds to one output feature type for the selected Writer.

Output Ports

The number of output ports depends on how the Output Ports parameter section is configured.

Provides summary of features written.

Parameters

Group By

If Group By attributes are specified, the input features will be partitioned and written per group.

If you do not choose any Group By attributes, all features are written together.

Complete Groups

Select the point in processing at which groups are processed:

When All Features Received

This is the default behavior. Processing will only occur in this transformer once all input is present.

When Group Changes (Advanced)

This transformer will process input groups in order. Changes of the value of the Group By parameter on the input stream will trigger processing on the currently accumulating group. This may improve overall speed (particularly with multiple, equally-sized groups), but could cause undesired behavior if input groups are not truly ordered.

There are two typical reasons for using When Group Changes (Advanced) . The first is incoming data that is intended to be processed in groups (and is already so ordered). In this case, the structure dictates Group By usage - not performance considerations.

The second possible reason is potential performance gains.

Performance gains are most likely when the data is already sorted (or read using a SQL ORDER BY statement) since less work is required of FME. If the data needs ordering, it can be sorted in the workspace (though the added processing overhead may negate any gains).

Sorting becomes more difficult according to the number of data streams. Multiple streams of data could be almost impossible to sort into the correct order, since all features matching a Group By value need to arrive before any features (of any feature type or dataset) belonging to the next group. In this case, using Group By with When All Features Received may be the equivalent and simpler approach.

Note: Multiple feature types and features from multiple datasets will not generally naturally occur in the correct order.

As with many scenarios, testing different approaches in your workspace with your data is the only definitive way to identify performance gains.

Format and Dataset

Select the Writer format, dataset and coordinate system, including any writer-specific parameters. For details on these parameters, see the documentation for the specific writer in the FME Form Readers/Writers help.

Feature Types

Shows the list of feature types. Select the feature type to access the feature type parameters. For details on feature type parameters, see the documentation for the specific writer in the FME Form Readers/Writers help.

To add a feature type, connect a new reader feature type or transformer to the Connect Input port, or click '+' to manually add a feature type or import a list of feature types from a dataset. To remove feature types, select and click '-'. To reorder feature types, select and click the up/down arrows.

The order of feature types does not dictate the order features are written.

Dataset

The left-hand pane list the names of current feature types that are defined/configured. There are two ways to add new feature type definitions:

  • By dragging and connecting a link to Connect Input port of the transformer. This creates a new port and feature type with information gathered from the incoming link such as attributes and its types.
  • By clicking on “+” button and then selecting “New” or “Import from Dataset…” option. This creates a blank feature type.

These feature types are analogous to Writer feature types on canvas and can be edited in same way.

Total Features Written

Name of the attribute that will contain the total number of features written to all the feature types

Feature Types List Name

Name of the attribute that will contain the names of all the feature types that are written in a FME list format

Output Ports

  • None: No additional output ports will be created.
  • One per Feature Type: An output port will be created for each input port.
  • Specified: An output port will be created for each of the selected input ports.

All output features are cached until all of the writing is finished, then the features are output through their respective ports.

Editing Transformer Parameters

Using a set of menu options, transformer parameters can be assigned by referencing other elements in the workspace. More advanced functions, such as an advanced editor and an arithmetic editor, are also available in some transformers. To access a menu of these options, click beside the applicable parameter. For more information, see Transformer Parameter Menu Options.

Defining Values

There are several ways to define a value for use in a Transformer. The simplest is to simply type in a value or string, which can include functions of various types such as attribute references, math and string functions, and workspace parameters. There are a number of tools and shortcuts that can assist in constructing values, generally available from the drop-down context menu adjacent to the value field.

Using the Text Editor

The Text Editor provides a convenient way to construct text strings (including regular expressions) from various data sources, such as attributes, parameters, and constants, where the result is used directly inside a parameter.

Text Editor

Using the Arithmetic Editor

The Arithmetic Editor provides a convenient way to construct math expressions from various data sources, such as attributes, parameters, and feature functions, where the result is used directly inside a parameter.

Arithmetic Editor

Conditional Values

Set values depending on one or more test conditions that either pass or fail.

Parameter Condition Definition Dialog

Content

Expressions and strings can include a number of functions, characters, parameters, and more.

When setting values - whether entered directly in a parameter or constructed using one of the editors - strings and expressions containing String, Math, Date/Time or FME Feature Functions will have those functions evaluated. Therefore, the names of these functions (in the form @<function_name>) should not be used as literal string values.

String Functions

These functions manipulate and format strings.

Special Characters

 A set of control characters is available in the Text Editor.

Math Functions

Math functions are available in both editors.
Date/Time Functions Date and time functions are available in the Text Editor.

Math Operators

These operators are available in the Arithmetic Editor.

FME Feature Functions

These return primarily feature-specific values.

FME Parameters

FME and workspace-specific parameters may be used.
Creating and Modifying User Parameters Create your own editable parameters.

Dialog Options - Tables

Transformers with table-style parameters have additional tools for populating and manipulating values.

Row Reordering

Enabled once you have clicked on a row item. Choices include:

  • Add a row
  • Remove a row
  • Move current row up one
  • Move current row down one
  • Move current row to top
  • Move current row to bottom

Cut, Copy, and Paste

Enabled once you have clicked on a row item. Choices include:

  • Cut a row - delete and copy to clipboard
  • Copy a row to the clipboard
  • Paste a row from the clipboard

Cut, copy, and paste may be used within a transformer, or between transformers.

Filter

Start typing a string, and the matrix will only display rows matching those characters. Searches all columns. This only affects the display of attributes within the transformer - it does not alter which attributes are output.

Import

Import populates the table with a set of new attributes read from a dataset. Specific application varies between transformers.

Reset/Refresh

Generally resets the table to its initial state, and may provide additional options to remove invalid entries. Behavior varies between transformers.

Note: Not all tools are available in all transformers.

FME Community

The FME Community is the place for demos, how-tos, articles, FAQs, and more. Get answers to your questions, learn from other users, and suggest, vote, and comment on new features.

Search for all results about the FeatureWriter on the FME Community.