August 17, 2023

tFileInputARFF – Docs for ESB 5.x



tFileInputARFF properties

Component Family




tFileInputARFF reads a ARFF file
row by row, with simple separated fields.


This component opens a file and reads it row by row, in order to
divide it in fields and to send these fields to the next component,
as defined in the schema, through a Row connection.

Basic settings

Property type

Either Built-in or Repository.

Since version 5.6, both the Built-In mode and the Repository mode are
available in any of the Talend solutions.



Built-in: No property data stored



Repository: Select the repository
file where the properties are stored. The fields that follow are
completed automatically using the data retrieved.



Click this icon to open a connection wizard and store the Excel
file connection parameters you set in the component’s Basic settings view.

For more information about setting up and storing file connection
parameters, see Talend Studio User


File Name

Name and path of the ARFF file and/or variable to be

For further information about how to define and use a variable in
a Job, see Talend Studio
User Guide.


Schema and Edit

A schema is a row description, it defines the number of fields to be processed and
passed on to the next component. The schema is either Built-in or stored remotely in the

Since version 5.6, both the Built-In mode and the Repository mode are
available in any of the Talend solutions.

Click Edit schema to make changes to the schema. If the
current schema is of the Repository type, three options are

  • View schema: choose this option to view the
    schema only.

  • Change to built-in property: choose this option
    to change the schema to Built-in for local

  • Update repository connection: choose this option to change
    the schema stored in the repository and decide whether to propagate the changes to
    all the Jobs upon completion. If you just want to propagate the changes to the
    current Job, you can select No upon completion and
    choose this schema metadata again in the [Repository



Built-in: The schema will be
created and stored locally for this component only. Related topic:
see Talend Studio User Guide.



Repository: The schema already
exists and is stored in the Repository, hence can be reused in
various projects and Job flowcharts. Related topic: see
Talend Studio User

Advanced settings


Select the encoding type from the list or select Custom and define it manually. This field
is compulsory for DB data handling.


tStatCatcher Statistics

Select this check box to gather the processing metadata at the Job
level as well as at each component level.

Global Variables

NB_LINE: the number of rows processed. This is an After
variable and it returns an integer.

ERROR_MESSAGE: the error message generated by the
component when an error occurs. This is an After variable and it returns a string. This
variable functions only if the Die on error check box is
cleared, if the component has this check box.

A Flow variable functions during the execution of a component while an After variable
functions after the execution of the component.

To fill up a field or expression with a variable, press Ctrl +
to access the variable list and choose the variable to use from it.

For further information about variables, see Talend Studio
User Guide.


Use this component to read a file and separate the fields with the
specified separator.


The activity of this component can be logged using the log4j feature. For more information on this feature, see Talend Studio User

For more information on the log4j logging levels, see the Apache documentation at


Due to license incompatibility, one or more JARs required to use this component are not
provided. You can install the missing JARs for this particular component by clicking the
Install button on the Component tab view. You can also find out and add all missing JARs easily on
the Modules tab in the Integration perspective
of your studio. For details, see
or the section describing how to configure the Studio in the Talend Installation and Upgrade

Scenario: Display the content of a ARFF file

This scenario describes a two-component Job in which the rows of an ARFF file are
read, the delimited data is selected and the output is displayed in the Run view.

An ARFF file looks like the following:


It is generally made of two parts. The first part describes the data structure, that
is to say the rows which begin by @attribute and the second part comprises
the raw data, which follows the expression @data.


Dropping and linking components

  1. Drop the tFileInputARFF component from
    the Palette onto the workspace.

  2. In the same way, drop the tLogRow

  3. Right-click the tFileInputARFF and select
    Row > Main in the menu. Then, drag
    the link to the tLogRow, and click it. The
    link is created and appears.

Configuring the components

  1. Double-click the tFileInputARFF.

  2. In the Component view, in the File Name field, browse your directory in order
    to select your .arff file.

  3. In the Schema field, select Built-In.

  4. Click the […] button next to Edit schema to add column descriptions
    corresponding to the file to be read.

  5. Click on the Button_Plus.png button as many times as required to create the number
    of columns required, according to the source file. Name the columns as

  6. For every column, the Nullable check box
    is selected by default. Leave the check boxes selected, for all of the

  7. Click OK.

  8. In the workspace, double-click the tLogRow
    to display its Component view.

  9. Click the […] button next to Edit schema to check that the schema has been
    propagated. If not, click the Sync columns

Saving and executing the Job

  1. Press Ctrl+S to save your Job.

  2. Press F6 to execute your Job.


    The console displays the data contained in the ARFF file, delimited using
    a vertical line (the default separator).

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