io.cdap.wrangler.api.lineage

Interface Lineage

@Beta
public interface Lineage

This class Lineage defines a mutation defined by the directive that gets capture as lineage.

Directives have to implement this class to inject their mutations for lineage to be constructed.

The method lineage is invoked separately in the prepareRun phase of the pipeline execution. Before the method lineage is invoked, the framework ensures that the receipe is parsed and initialize on each directive that is included is called. All the class variables of the directive are available to be used within the lineage method.

Mutation captures all the changes the directive is going to be applying of the data. It has two major methods:

readable - This method is defined to provide the post transformation description of the mutation the directive is applying on data. Care should be taken to use the right tense as the lineage would be consumed by users after the transformation has been applied on the data. As best practise, it's highly recommended to use past-tense for describing the transformations. Additionally, the language of the description is not trying to provide complete details and configuration, but actually focusing on operations that directive has performed on data.
• relation - This methods defines the relations between various columns either being used as target or source for performing the data transformation.

Following are few examples of how the method can be implemented:

See Also:

Mutation, Relation, Many

Method Summary

Modifier and Type	Method and Description
Mutation	lineage() Returns a Mutation that can be used to generate lineage.

Method Detail

lineage

Mutation lineage()

Returns a Mutation that can be used to generate lineage.

Returns:

a instance of Mutation object used to generate lineage.