tExtractJSONFields Storm properties (deprecated)

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.

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.

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.

JSON field

List of the JSON fields to be extracted.

Loop XPath query

Node within the JSON field, on which the loop is based.

Mapping

Column: schema defined to hold the data extracted from the JSON field.

XPath Query: XPath Query to specify the node within the JSON field.

Get nodes: select this check box to extract the JSON data of all the nodes specified in the XPath query list or select the check box next to a specific node to extract its JSON data only.

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

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.

Usage rule

If you have subscribed to one of the Talend solutions with Big Data, you can also use this component as a Storm component. In a Talend Storm Job, this component is used as an intermediate step and other components used along with it must be Storm components, too. They generate native Storm code that can be executed directly in a Storm system.

The Storm version does not support the use of the global variables.

You need to use the Storm Configuration tab in the Run view to define the connection to a given Storm system for the whole Job.

This connection is effective on a per-Job basis.

For further information about a Talend Storm Job, see the sections describing how to create and configure a Talend Storm Job of the Talend Big Data Getting Started Guide .

Note that in this documentation, unless otherwise explicitly stated, a scenario presents only Standard Jobs, that is to say traditional Talend data integration Jobs.