tExtractPositionalFields – Docs for ESB 5.x

Component family

Processing/Fields

Function

tExtractPositionalFields
generates multiple columns from one column using
positional fields.

Purpose

tExtractPositionalFields allows
you to use a positional pattern to extract data from a formatted
string.

Basic settings

Field

Select an incoming field from the Field list to extract.

In the Map/Reduce version of this component,
the name of this field is Prev.Comp.Column
list, meaning the column list from the preceding
component.

Ignore NULL as the source data

Select this check box to ignore the Null value in the source data.

Clear this check box to generate the Null records that correspond
to the Null value in the source data.

Note this feature is not available in the
Map/Reduce version.

Customize

Select this check box to customize the data format of the
positional file and define the table columns:

Column: Select the column you want
to customize.

Size: Enter the column size.

Padding char: Type in between
inverted commas the padding character used, in order for it to be
removed from the field. A space by default.

Alignment: Select the appropriate
alignment parameter.

Pattern

Enter the pattern to use as basis for the extraction.

A pattern is length values separated by commas, interpreted as a
string between quotes. Make sure the values entered in this fields
are consistent with the schema defined.

Die on error

Clear the check box to skip any rows on error and complete the process for error-free rows.
When errors are skipped, you can collect the rows on error using a Row
> Reject link.

Schema and Edit
Schema

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 Repository.

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

Click Sync columns to retrieve the schema from the
previous component connected in the Job.

Built-in: You create the schema
and store it locally for the component. 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
Guide.

Property type

Either Built-in or Repository. This feature is available to
the Map/Reduce version only.

Built-in: no property data stored
centrally.

Repository: reuse properties
stored centrally under the Hadoop
Cluster node of the Repository tree.

The fields that come after are pre-filled in using the fetched
data.

For further information about the Hadoop
Cluster node, see the Getting Started Guide.

Advanced settings

Advanced separator (for number)

Select this check box to modify the separators used for
numbers.

Trim Column

Select this check box to remove leading and trailing whitespace
from all columns.

Check each row structure against
schema

Select this check box to check whether the total number of columns
in each row is consistent with the schema. If not consistent, an
error message will be displayed on the console.

tStatCatcher Statistics

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

Global Variables

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.

NB_LINE: the number of rows read by an input component or
transferred to an output component. This is an After variable and it returns an
integer.

The NB_LINE
variable is not available to the Map/Reduce version.

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 +
Space to access the variable list and choose the variable to use from it.

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

Usage

This component handles flow of data therefore it requires input
and output components. It allows you to extract data from a
delimited field, using a Row >
Main link, and enables you to
create a reject flow filtering data which type does not match the
defined type.

Usage in Map/Reduce Jobs

If you have subscribed to one of the Talend solutions with Big Data, you can also
use this component as a Map/Reduce component. In a Talend Map/Reduce Job, this
component is used as an intermediate step and other components used along with it must be
Map/Reduce components, too. They generate native Map/Reduce code that can be executed
directly in Hadoop.

You need to use the Hadoop Configuration tab in the
Run view to define the connection to a given Hadoop
distribution for the whole Job.

This connection is effective on a per-Job basis.

For further information about a Talend Map/Reduce Job, see the sections
describing how to create, convert and configure a Talend Map/Reduce Job of the
Talend Big Data Getting Started Guide.

Note that in this documentation, unless otherwise explicitly stated, a scenario presents
only Standard Jobs, that is to say traditional Talend data
integration Jobs, and non Map/Reduce Jobs.

Log4j

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

For more information on the log4j logging levels, see the Apache documentation at http://logging.apache.org/log4j/1.2/apidocs/org/apache/log4j/Level.html.

Limitation

n/a