tJavaRow Standard properties

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. When you create a Spark Job, avoid the reserved word line when naming the fields.

  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 Dynamic schema.

  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.

• Repository: You have already created the schema and stored it in the Repository. You can reuse it in various projects and Job designs.

  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.

  For more information, see Retrieving table schemas.

• 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.

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

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 more information about variables, see Using contexts and variables.

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 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.