com.cinchapi.concourse.importer

Interface Transformer

Functional Interface:

This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.

@FunctionalInterface
public interface Transformer

A Transformer is a routine that takes a key/value pair and potentially alters one or both of them, prior to import.

Sometimes, raw data from a source must be modified before being imported into Concourse, for example:

• Modifying keys by changing their case or stripping illegal characters
• Normalizing values, for example, converting strings to a specific case or sanitizing
• Compacting representation by values from an enumerated set of values to a simple integer
• Constructing a link or resolvable link

Method Summary

Modifier and Type	Method and Description
KeyValue<String,Object>	transform(String key, String value) Potentially transform one or both of the key/value pair.

Method Detail

transform

@Nullable
KeyValue<String,Object> transform(String key,
                                            String value)

Potentially transform one or both of the key/value pair. If no transformation should occur, it is acceptable to return null to inform the caller that the import values are fine. Otherwise, the preferred pair should be wrapped in a KeyValue object.

Parameters:

key - the raw key to potentially transform

value - the raw value to potentially transform; in which case, it is acceptable to return any kind of object, but it is recommended to return an encoded String (i.e. don't return a Link object, but return a string that encodes a link (@record@) instead)

Returns:

a KeyValue object that contains the transformed key/value pair or null if no transformation occurred