<?php
/*
* This file is part of the Symfony package.
*
* (c) Fabien Potencier <fabien@symfony.com>
*
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*/
namespace Symfony\Component\Form;
use Symfony\Component\Form\Exception\TransformationFailedException;
/**
* Transforms a value between different representations.
*
* @author Bernhard Schussek <bschussek@gmail.com>
*/
interface DataTransformerInterface
{
/**
* Transforms a value from the original representation to a transformed representation.
*
* This method is called on two occasions inside a form field:
*
* 1. When the form field is initialized with the data attached from the datasource (object or array).
* 2. When data from a request is submitted using {@link Form::submit()} to transform the new input data
* back into the renderable format. For example if you have a date field and submit '2009-10-10'
* you might accept this value because its easily parsed, but the transformer still writes back
* "2009/10/10" onto the form field (for further displaying or other purposes).
*
* This method must be able to deal with empty values. Usually this will
* be NULL, but depending on your implementation other empty values are
* possible as well (such as empty strings). The reasoning behind this is
* that value transformers must be chainable. If the transform() method
* of the first value transformer outputs NULL, the second value transformer
* must be able to process that value.
*
* By convention, transform() should return an empty string if NULL is
* passed.
*
* @param mixed $value The value in the original representation
*
* @return mixed The value in the transformed representation
*
* @throws TransformationFailedException When the transformation fails.
*/
public function transform($value);
/**
* Transforms a value from the transformed representation to its original
* representation.
*
* This method is called when {@link Form::submit()} is called to transform the requests tainted data
* into an acceptable format for your data processing/model layer.
*
* This method must be able to deal with empty values. Usually this will
* be an empty string, but depending on your implementation other empty
* values are possible as well (such as empty strings). The reasoning behind
* this is that value transformers must be chainable. If the
* reverseTransform() method of the first value transformer outputs an
* empty string, the second value transformer must be able to process that
* value.
*
* By convention, reverseTransform() should return NULL if an empty string
* is passed.
*
* @param mixed $value The value in the transformed representation
*
* @return mixed The value in the original representation
*
* @throws TransformationFailedException When the transformation fails.
*/
public function reverseTransform($value);
}
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