tJavaRow

Provides a code editor that lets you enter the Java code to be applied to each row
of the flow.

tJavaRow allows you to enter customized
code which you can integrate in a Talend program.

Depending on the Talend solution you
are using, this component can be used in one, some or all of the following Job
frameworks:

Standard: see tJavaRow Standard properties.

The component in this framework is generally available.
Spark Batch: see tJavaRow properties for Apache Spark Batch.

The component in this framework is available only if you have subscribed to one
of the
Talend
solutions with Big Data.
Spark Streaming: see tJavaRow properties for Apache Spark Streaming.

The component in this framework is available only if you have subscribed to Talend Real-time Big Data Platform or Talend Data
Fabric.

tJavaRow Standard properties

These properties are used to configure tJavaRow running in the Standard Job framework.

The Standard
tJavaRow component belongs to the Custom Code family.

The component in this framework is generally available.

Basic settings

Schema and Edit Schema	A schema is a row description. It defines the number of fields (columns) to be processed and passed on to the next component. The schema is either Built-In or stored remotely in the Repository. This component offers the advantage of the dynamic schema feature. This allows you to retrieve unknown columns from source files or to copy batches of columns from a source without mapping each column individually. For further information about dynamic schemas, see Talend Studio User Guide. This dynamic schema feature is designed for the purpose of retrieving unknown columns of a table and is recommended to be used for this purpose only; it is not recommended for the use of creating tables.
	Built-In: You create and store the schema locally for this component only. Related topic: see Talend Studio User Guide.
	Repository: You have already created the schema and stored it in the Repository. You can reuse it in various projects and Job designs. Related topic: see Talend Studio User Guide. When the schema to be reused has default values that are integers or functions, ensure that these default values are not enclosed within quotation marks. If they are, you must remove the quotation marks manually. You can find more details about how to verify default values in retrieved schema in Talend Help Center (https://help.talend.com).
	Click Edit schema to make changes to the schema. If the current schema is of the Repository type, three options are available: 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 changes. 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 Content] window. Click Sync columns to retrieve the schema from the previous component connected in the Job.
Generate code	Click this button to automatically generate the code in the Code field to map the columns of the input schema with those of the output schema. This generation does not change anything in your schema. The principle of this mapping is to relate the columns that have the same column name. Then you can adapt the generated code depending on the actual map you need.
Code	Enter the Java code to be applied to each line of the data flow.

Advanced settings

Import	Enter the Java code to import, if necessary, external libraries used in the Code field of the Basic settings view.
tStatCatcher Statistics	Select this check box to collect the log data at a component level..

Global Variables

Global Variables	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. 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 + Space to access the variable list and choose the variable to use from it. For further information about variables, see Talend Studio User Guide. To enter a global variable (for example COUNT of tFileRowCount) in the Code box, you need to type in the entire piece of code manually, that is to say ((Integer)globalMap.get(“tFileRowCount_COUNT”)).

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.

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

For further information about variables, see
Talend Studio

User Guide.

To enter a global variable (for example COUNT of
tFileRowCount) in the Code box, you need to type in the entire piece of code manually, that is to
say ((Integer)globalMap.get(“tFileRowCount_COUNT”)).

Usage

Usage rule	This component is used as an intermediary between two other components. It must be linked to both an input and an output component.
Function	tJavaRow allows you to enter customized code which you can integrate in a Talend programme. With tJavaRow, you can enter the Java code to be applied to each row of the flow.
Purpose	tJavaRow allows you to broaden the functionality of Talend Jobs, using the Java language.
Limitation	Knowledge of Java language is necessary.

Scenario: Transforming data
line by line using tJavaRow

In this scenario, the information of a few cities read from an input delimited file is
transformed using Java code through the tJavaRow
component and printed on the console.

Setting up the Job

Drop a tFileInputDelimited component and
a tJavaRow component from the Palette onto the design workspace, and label them
to better identify their roles in the Job.
Connect the two components using a Row >
Main connection.

Configuring the components

Double-click the tFileInputDelimited
component to display its Basic settings
view in the Component tab.

In the File name/Stream field, type in
the path to the input file in double quotation marks, or browse to the path
by clicking the […] button, and define
the first line of the file as the header.

In this example, the input file has the following content:

City;Population;LandArea;PopDensity
Beijing;10233000;1418;7620
Moscow;10452000;1081;9644
Seoul;10422000;605;17215
Tokyo;8731000;617;14151
New York;8310000;789;10452

City;Population;LandArea;PopDensity

Beijing;10233000;1418;7620

Moscow;10452000;1081;9644

Seoul;10422000;605;17215

Tokyo;8731000;617;14151

New York;8310000;789;10452

Click the […] button next to Edit
schema to open the [Schema] dialog box, and
define the data structure of the input file. Then, click OK to validate the schema setting and close the
dialog box.
Double-click the tJavaRow component to
display its Basic settings view in the
Component tab.
Click Sync columns to make sure that the
schema is correctly retrieved from the preceding component.

In the Code field, enter the code to be
applied on each line of data based on the defined schema columns.

In this example, we want to transform the city names to upper case, group
digits of numbers larger than 1000 using the thousands separator for ease of
reading, and print the data on the console:

System.out.print("
" + input_row.City.toUpperCase() + ":");
System.out.print("
 - Population: " 
+ FormatterUtils.format_Number(String.valueOf(input_row.Population), ',', '.') + " people");
System.out.print("
 - Land area: " 
+ FormatterUtils.format_Number(String.valueOf(input_row.LandArea), ',', '.') 
+ " km2");
System.out.print("
 - Population density: " 
+ FormatterUtils.format_Number(String.valueOf(input_row.PopDensity), ',', '.') + " people/km2
");

System.out.print("

" + input_row.City.toUpperCase() + ":");

System.out.print("

- Population: "

+ FormatterUtils.format_Number(String.valueOf(input_row.Population), ',', '.') + " people");

System.out.print("

- Land area: "

+ FormatterUtils.format_Number(String.valueOf(input_row.LandArea), ',', '.')

+ " km2");

System.out.print("

- Population density: "

+ FormatterUtils.format_Number(String.valueOf(input_row.PopDensity), ',', '.') + " people/km2

");

Note:

In the Code field, input_row refers to the link that connects to
tJavaRow.

Saving and executing the Job

Press Ctrl+S to save your Job.
Press F6 or click Run on the Run tab to
execute the Job.

The city information is transformed by the Java code set through tJavaRow and displayed on the console.

Scenario: Using tJavaRow to handle file content based on a dynamic schema

This scenario applies only to a subscription-based Talend solution.

This scenario describes a three-component Job that uses Java code through a tJavaRow component to display the content of an input file
and pass it to the output component. As all the components in this Job support the
dynamic schema feature, we can leverage this feature to save the time of configuring
each column of the schema.

Setting up the Job

Drop tFileInputDelimited, tJavaRow, and tFileOutputDelimited from the Palette onto the design workspace, and label them according
to their roles in the Job.
Connect the components in a series using Row > Main links.

Configuring the input and output components

Double-click the tFileInputDelimited
component, which is labeled Source, to
display its Basic settings view.

Warning:

The dynamic schema feature is only supported in Built-In mode and requires the input file
to have a header row.
In the File name/Stream field, type in
the path to the input file in double quotation marks, or browse to the path
by clicking the […] button.
In the Header field, type in 1 to define the first line of the file as the
header.
Click the […] button next to Edit schema to open the [Schema] dialog box.
Click the [+] button to add a column,
give a name to the column, dyna in this
example, and select Dynamic from the
Type list. This dynamic column will
retrieve the three columns, FirstName,
LastName and Address, of the input file.
Click OK to validate the setting and
close the dialog box.
Double-click the tFileOutputDelimited
component, which is labeled Target, to
display its Basic settings view.
Define the output file path in the File
Name field.
Select the Include Header check box to
include the header in the output file. Leave all the other settings are they
are.

Configuring the tJavaRow component

Double-click tJavaRow to display its
Basic settings view and define the
components properties.
Click Sync columns to make sure that the
schema is correctly retrieved from the preceding component.
In the Code field, enter the following
code to display the content of the input file and pass the data to the next
component based on the defined dynamic schema column:

System.out.println(input_row.dyna); output_row.dyna = input_row.dyna;

1
2

System.out.println(input_row.dyna);
output_row.dyna = input_row.dyna;

Note:

In the Code field, input_row and output_row correspond to the links to and from tJavaRow.

Saving and executing the Job

Press Ctrl+S to save your Job.
Pressing F6, or click Run on the Run
tab to execute the Job.

The content of the input file is displayed on the console and written to
the output file.