com.bazaarvoice.jolt

Interface ContextualTransform

All Superinterfaces:

JoltTransform

All Known Implementing Classes:

Chainr

public interface ContextualTransform
extends JoltTransform

Interface for Jolt Transforms that can incorporate context information along with the source input JSON. These Jolt Transforms should still be stateless, in that multiple threads should be able to call the transform method simultaneously.

Method Summary

Methods

Modifier and Type	Method and Description
Object	transform(Object input, Map<String,Object> context) Execute a transform on some input JSON with optionally provided "context" and return the result.

Method Detail

transform

Object transform(Object input,
               Map<String,Object> context)

Execute a transform on some input JSON with optionally provided "context" and return the result. The "context" allows transforms to tweak their behavior based upon criteria outside of the input Json object. The canonical example for the need to have Transforms consider "context" is a Transform that creates urls based upon input data. Should it generate "http" or "https" urls? Most likely the input Json data does not provide any guidance. This is what the "context" is for. It allows the consumer of the Transform to specialize itself based on data outside the scope of the input Json. Without the "context" notion you would instead create a HttpUrlTransform and a HttpsUrlTransform. This creates problems when you want to used them as part of a larger Chainr Transform, as you would need to create two Chainrs that are almost the same. The number of Chainrs needed grows combinatorially as you add other context sensitive transforms.

Parameters:

input - the JSON object to transform in plain vanilla Jackson Map style

context - information outside of the input JSON that needs to be taken into account when doing the transform

Returns:

the results of the transformation

Throws:

TransformException - if there are issues with the transform