tExtractJSONFields Standard properties

Property type

Either Built-In or Repository.

Built-In: No property data stored centrally.

Repository: Select the repository file where the properties are stored.

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.

• 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.

• 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.

Read By

Select a way of extracting JSON data in the file.

• JsonPath: Extracts JSON data based on the JSONPath query. With this option selected, you need to select a JSONPath API version from the API version drop-down list. It is recommended to read data by JSONPath in order to gain better performance.

• Xpath: Extracts JSON data based on the XPath query.

JSON field

List of the JSON fields to be extracted.

Loop Jasonpath query

Enter the Jsonpath or XPath of the node on which the loop is based.

Note if you have selected Xpath from the Read by drop-down list, the Loop Xpath query field is displayed instead.

Mapping

Complete this table to map the columns defined in the schema to the corresponding JSON nodes.

• Column: The Column cells are automatically filled with the defined schema column names.

• Json query/JSONPath query: Specify the JSONPath node that holds the desired data. For more information about JSONPath expressions, see http://goessner.net/articles/JsonPath/.

  This column is available only when JsonPath is selected from the Read By list.

• XPath query: Specify the XPath node that holds the desired data.

  This column is available only when Xpath is selected from the Read By list.

• Get Nodes: Select this check box to extract the JSON data of all the nodes or select the check box next to a specific node to extract the data of that node.

  This column is available only when Xpath is selected from the Read By list.

• Is Array: select this check box when the JSON field to be extracted is an array instead of an object.

  This column is available only when Xpath is selected from the Read By list.

Die on error

Select the check box to stop the execution of the Job when an error occurs.

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.

Use the loop node as root

Select this check box to use the loop node as the root for querying the file.

The loop node is set in the Loop Json query text frame in the Basic Settings view. If this option is checked, only the child elements of the loop node are available for querying; otherwise, both the parent elements and the child elements of the loop node can be queried. You can specify a parent element through JSON path syntax.

This check box is available only when JsonPath is selected in the Read By drop-down list of the Basic settings view.

Encoding

Select the encoding from the list or select Custom and define it manually. This field is compulsory for database data handling. The supported encodings depend on the JVM that you are using. For more information, see https://docs.oracle.com.

tStatCatcher Statistics

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

NB_LINE

The number of rows processed. 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 selected.

Usage rule

This component is an intermediate component. It needs an input and an output components.

Limitation

Due to license incompatibility, one or more JARs required to use this component are not provided. You can install the missing JARs for this particular component by clicking the Install button on the Component tab view. You can also find out and add all missing JARs easily on the Modules tab in the Integration perspective of your studio. For details, see Installing external modules. You can find more details about how to install external modules in Talend Help Center (https://help.talend.com).