Scenario: Checking for the presence of a file and creating it if it does not exist - 6.1

Talend Components Reference Guide

EnrichVersion
6.1
EnrichProdName
Talend Big Data
Talend Big Data Platform
Talend Data Fabric
Talend Data Integration
Talend Data Management Platform
Talend Data Services Platform
Talend ESB
Talend MDM Platform
Talend Open Studio for Big Data
Talend Open Studio for Data Integration
Talend Open Studio for Data Quality
Talend Open Studio for ESB
Talend Open Studio for MDM
Talend Real-Time Big Data Platform
task
Data Governance
Data Quality and Preparation
Design and Development
EnrichPlatform
Talend Studio

This scenario describes a simple Job that: checks if a given file exists, displays a graphical message to confirm that the file does not exist, reads the input data in another given file and writes it in an output delimited file.

Dropping and linking the components

  1. Drop the following components from the Palette onto the design workspace: tFileExist, tFileInputDelimited, tFileOutputDelimited, and tMsgBox.

  2. Connect tFileExist to tFileInputDelimited using an OnSubjobOk and to tMsgBox using a Run If link.

  3. Connect tFileInputDelimited to tFileOutputDelimite using a Row Main link.

Configuring the components

  1. In the design workspace, select tFileExist and click the Component tab to define its basic settings.

  2. In the File name field, enter the file path or browse to the file you want to check if it exists or not.

  3. In the design workspace, select tFileInputDelimited and click the Component tab to define its basic settings.

  4. Browse to the input file you want to read to fill out the File Name field.

    Warning

    If the path of the file contains some accented characters, you will get an error message when executing your Job. For more information regarding the procedures to follow when the support of accented characters is missing, see the Talend Installation Guide.

  5. Set the row and field separators in their corresponding fields.

  6. Set the header, footer and number of processed rows as needed. In this scenario, there is one header in our table.

  7. Set Schema to Built-in and click the Edit schema button to define the data to pass on to the tFileOutputDelimited component. Define the data present in the file to read, file2 in this scenario.

    For more information about schema types, see Talend Studio User Guide.

    The schema in file2 consists of five columns: Num, Ref, Price, Quant, and tax.

  8. In the design workspace, select the tFileOutputDelimited component.

  9. Click the Component tab to define the basic settings of tFileOutputDelimited.

  10. Set property type to Built-in.

  11. In the File name field, press Ctrl+Space to access the variable list and select the global variable FILENAME.

  12. Set the row and field separators in their corresponding fields.

  13. Select the Include Header check box as file2 in this scenario includes a header.

  14. Set Schema to Built-in and click Sync columns to synchronize the output file schema (file1) with the input file schema (file2).

  15. In the design workspace, select the tMsgBox component.

  16. Click the Component tab to define the basic settings of tMsgBox.

  17. Click the If link to display its properties in the Basic settings view.

  18. In the Condition panel, press Ctrl+Space to access the variable list and select the global variable EXISTS. Type an exclamation mark before the variable to negate the meaning of the variable.

Saving and executing the Job

  1. Press Ctrl+S to save your Job.

  2. Press F6 or click the Run button in the Run tab to execute it.

A dialog box appears to confirm that the file does not exists.

Click OK to close the dialog box and continue the Job execution process. The missing file, file1 in this scenario, got written in a delimited file in the defined place.