Skip to main content

DirectTransform class

The DirectTransform class is a basic implementation of the PropertyHandlerInterface that passes property names and values through unchanged, with an optional value transformation function.

This class serves as:

  1. A simple property handler that doesn't modify property names
  2. A base class for more complex property handlers that need custom value transformations
  3. The parent class for other property handlers like CamelToSnakeCase, SnakeToCamelCase, and PropertyNameMapper

Basic Usage​

The DirectTransform class performs an identity mapping of property names:

use ByJG\Serializer\ObjectCopy;
use ByJG\Serializer\PropertyHandler\DirectTransform;

$source = ["name" => "John", "age" => 30];
$target = new stdClass();

// Property names will remain the same
ObjectCopy::copy($source, $target, new DirectTransform());

// Result:
// $target->name = "John";
// $target->age = 30;

Value Transformation​

While property names remain unchanged, you can transform values by providing a closure to the constructor:

use ByJG\Serializer\ObjectCopy;
use ByJG\Serializer\PropertyHandler\DirectTransform;

$source = ["name" => "John", "age" => 30];
$target = new stdClass();

// Value transformation function
$valueHandler = function ($propertyName, $targetName, $value, $instance = null) {
    if ($propertyName === 'name') {
        return strtoupper($value);
    }
    if ($propertyName === 'age') {
        return $value + 1;
    }
    return $value;
};

ObjectCopy::copy($source, $target, new DirectTransform($valueHandler));

// Result:
// $target->name = "JOHN";
// $target->age = 31;

The $valueHandler closure receives four parameters for flexible value transformation. For complete documentation of value handler parameters and patterns, see the Property Handlers Guide.

Accessing the Source Object​

The value handler can access the complete source object through the $instance parameter:

$source = new stdClass();
$source->firstName = "John";
$source->lastName = "Doe";
$source->age = 30;

$target = new stdClass();

// Value handler that combines properties
$valueHandler = function ($propertyName, $targetName, $value, $instance = null) {
    if ($propertyName === 'firstName' && $instance !== null) {
        // Create a full name using both firstName and lastName properties
        return $value . ' ' . ($instance->lastName ?? '');
    }
    return $value;
};

ObjectCopy::copy($source, $target, new DirectTransform($valueHandler));

// Result:
// $target->firstName = "John Doe";
// $target->lastName = "Doe";
// $target->age = 30;

Custom Property Handlers​

The DirectTransform class serves as the base class for more specialized property handlers:

  • CamelToSnakeCase: Converts camelCase properties to snake_case
  • SnakeToCamelCase: Converts snake_case properties to camelCase
  • PropertyNameMapper: Maps specific property names to different target names

For detailed examples of these specialized handlers, see the ObjectCopy documentation.