ch.jalu.configme.beanmapper.transformer

Class TypedTransformer<S,R>

java.lang.Object

ch.jalu.configme.beanmapper.transformer.TypedTransformer<S,R>

Type Parameters:

S - the source type

R - the result type

All Implemented Interfaces:

Transformer

public abstract class TypedTransformer<S,R>
extends Object
implements Transformer

Typed implementation of Transformer for convenient extension.

Constructor Summary

Constructors

Constructor and Description
TypedTransformer(Class<S> sourceType, Class<R> resultType) Constructs a transformer for the specified source and result type.

Method Summary

Modifier and Type	Method and Description
protected abstract R	safeTransform(Class<? extends R> type, S value) Transforms the given value to the provided type.
Object	transform(TypeInformation<?> type, Object value) Transforms the provided value to the requested type, if possible.

Methods inherited from class java.lang.Object

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

Constructor Detail

TypedTransformer

public TypedTransformer(Class<S> sourceType,
                        Class<R> resultType)

Constructs a transformer for the specified source and result type. If other types are encountered the safeTransform(Class, Object) will not be called. To define a transformer that converts Strings to Integers, pass String and Integer. To convert anything to a String, you should pass Object and String as types.

Note that primitive types are not included, e.g. a TypedTransformer<Boolean, Object> will skip values where value.getClass() == boolean.class.

Parameters:

sourceType - the type the source object must be of to be considered by this transformer

resultType - the type the target type needs to extend or be equal to in order to be considered by this transformer

Method Detail

transform

public Object transform(TypeInformation<?> type,
                        Object value)

Description copied from interface: Transformer

Transforms the provided value to the requested type, if possible.

The contract is that a transformer must return an object of type T for a given type of TypeInformation<T>. This is not forced in the signature to allow handling primitive types, as well as to avoid casting nightmares.

Specified by:

transform in interface Transformer

Parameters:

type - the type to map to

value - the value to transform from

Returns:

the value of the given type, or null if not possible

safeTransform

@Nullable
protected abstract R safeTransform(Class<? extends R> type,
                                             S value)

Transforms the given value to the provided type. This method is only called if type is equal to R or a subclass thereof, and if value is an object of type S. The object is never null.

Parameters:

type - the desired type of the conversion result

value - the value to convert

Returns:

the converted value, or null if not applicable