Package com.bazaarvoice.jolt
Interface ContextualTransform
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- All Superinterfaces:
JoltTransform
- All Known Implementing Classes:
Chainr
,Chainr.ContextualTransformAdapter
,Modifier
,Modifier.Defaultr
,Modifier.Definr
,Modifier.Overwritr
public interface ContextualTransform extends JoltTransform
Interface for Jolt Transforms that can incorporate context information along with the source input JSON. These Jolt Transforms should be stateless, thus allowing multiple threads to call the transform method simultaneously.
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Method Summary
All Methods Instance Methods Abstract Methods Modifier and Type Method Description java.lang.Object
transform(java.lang.Object input, java.util.Map<java.lang.String,java.lang.Object> context)
Execute a transform on some input JSON with optionally provided "context" and return the result.
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Method Detail
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transform
java.lang.Object transform(java.lang.Object input, java.util.Map<java.lang.String,java.lang.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 exponentially as you add other context sensitive transforms.- Parameters:
input
- the JSON object to transform in plain vanilla Jackson Mapstyle 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
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