tJavaRow properties for Apache Spark Batch
These properties are used to configure tJavaRow running in the Spark Batch Job framework.
The Spark Batch tJavaRow component belongs to the Custom Code family.
The component in this framework is available in all subscription-based Talend products with Big Data and Talend Data Fabric.
Basic settings
Properties | Description |
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Schema and Edit Schema |
|
Map type |
Select the type of the Map transformation you need to write. This allows the component to automatically select the method accordingly and declare the variables to be used in your custom code. The available types are:
For further information about these methods, see Apache Spark's documentation about its Java API in https://spark.apache.org/docs/latest/api/java/index.html. |
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 generated sample code shows what the pre-defined variables are for the input and the output RDDs and how these variables can be used. |
Code |
Write the custom body of the method you have selected from the Map type drop-down list. You need to use the input schema and the output schema to manage the columns of the input and the output RDD records. This custom code is applied on a row-by-row basis in the RDD records. For example, the input schema contains a user column, then you need to use the input.user variable to get the user column of each input record. For further information about the available variables in writing the custom code, see the default comment displayed in this field. |
Advanced settings
Properties | Description |
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Import |
Enter the Java code to import, if necessary, external libraries used in the Code field of the Basic settings view. |
Global Variables
Variables | Description |
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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. 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
Usage guidance | Description |
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Usage rule |
This component is used as an intermediate step. This component, along with the Spark Batch component Palette it belongs to, appears only when you are creating a Spark Batch Job. Note that in this documentation, unless otherwise explicitly stated, a scenario presents only Standard Jobs, that is to say traditional Talend data integration Jobs. |
Spark Connection |
In the Spark
Configuration tab in the Run
view, define the connection to a given Spark cluster for the whole Job. In
addition, since the Job expects its dependent jar files for execution, you must
specify the directory in the file system to which these jar files are
transferred so that Spark can access these files:
This connection is effective on a per-Job basis. |
Limitation |
Knowledge of Spark and Java language is necessary. |