io.cdap.transformation.api

Interface Transformation

@Beta
public interface Transformation

Interface for Transformation plugin

Field Summary

Fields

Modifier and Type	Field and Description
static String	PLUGIN_TYPE

Method Summary

Modifier and Type	Method and Description
void	initialize(TransformationContext context) Initialize the Transformation plugin.
void	transformSchema(MutableRowSchema rowSchema) Apply transformation on the schema of a row.
void	transformValue(MutableRowValue rowValue) Apply transformation on the value of a row.

Field Detail

PLUGIN_TYPE

static final String PLUGIN_TYPE

See Also:

Constant Field Values

Method Detail

initialize

void initialize(TransformationContext context)
         throws Exception

Initialize the Transformation plugin.

Parameters:

context - the transformation context

Throws:

Exception - if the transformation can not be correctly initialized.

transformSchema

void transformSchema(MutableRowSchema rowSchema)
              throws Exception

Apply transformation on the schema of a row. This method will be invoked when the schema of a row needs to be transformed. For example : 1. When the output Schema of the impacted table needs to be calculated at design time. 2. when a StructuredRecord needs to be transformed at runtime, the schema StructuredRecord needs to be transformed.

Parameters:

rowSchema - the mutable row schema

Throws:

Exception

transformValue

void transformValue(MutableRowValue rowValue)
             throws Exception

Apply transformation on the value of a row. This method will be invoked when the value a row needs to be transformed. For example when a StructuredRecord needs to be transformed at runtime. This interface probably will change in the future to support multiple rows, e.g. flatten one row to multiple rows.

Parameters:

rowValue - the mutable row value

Throws:

Exception