com.cinchapi.etl

Class ScriptedTransformer

java.lang.Object

com.cinchapi.etl.ScriptedTransformer

All Implemented Interfaces:

Transformer, java.io.Serializable

public class ScriptedTransformer
extends java.lang.Object
implements Transformer, java.io.Serializable

A Transformer that uses a ScriptEngine compatible script to transform data.

The provided script has access to the key and value that are candidates for transformation. The key is available via a variable named key and the value is available via a variable named value.

The last line of the script determines the return value of the transformation. If an Object or Map-like value is returned from the script, the same is returned from the transform(String, Object) function. Otherwise, scalar values are assumed to be transformations to the original value. In those instances, the original key is preserved and the original value is replaced by the script's returned value.

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	ScriptedTransformer.Builder Base ScriptedTransformer.Builder for ScriptedTransformers.
static class	ScriptedTransformer.JavascriptTransformerBuilder A ScriptedTransformer.Builder for Javascript based ScriptedTransformers.

Method Summary

Modifier and Type	Method and Description
java.util.Map<java.lang.String,java.lang.Object>	transform(java.lang.String key, java.lang.Object value) Potentially transform the provided key and value pair.
static ScriptedTransformer.Builder	usingJavascript() Return a builder that will create a ScriptedTransformer that uses a javascript interpreter.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface com.cinchapi.etl.Transformer

deserialize, serialize, transform, transform

Method Detail

usingJavascript

public static ScriptedTransformer.Builder usingJavascript()

Return a builder that will create a ScriptedTransformer that uses a javascript interpreter.

Returns:

the builder

transform

public java.util.Map<java.lang.String,java.lang.Object> transform(java.lang.String key,
                                                                  java.lang.Object value)

Description copied from interface: Transformer

Potentially transform the provided key and value pair.

There are four possible transformation scenarios:

1. Neither the key or value changes
2. Only the key changes
3. Only the value changes
4. Both the key and value change

In scenario 1, this method returns null. In the other scenarios, this method returns a Map which contains the data that will replace the original key and value. So, if the input parameters are part of a larger data map, the caller should merge the data from this map with the source data.

Even though the inputs to this method are simple, a Map is returned to allow for complex transformations. For example,

• You can transform a single value into multiple values by including multiple objects in the associated values collection.
• You can transform a single key/value pair into multiple key/value pairs by including multiple keys in the returned map

For the basic case of transforming a single key/value pair into another single key/value pair, you should use the Transformation#to(Object, Object) utility.

Specified by:

transform in interface Transformer

Parameters:

key - the raw key to potentially transform

value - the raw value to potentially transform

Returns:

the transformation