Sometimes you have to pass an object data to another object, or to another layer of your application (who said controller/view ?), while ensuring that the receiving entity will not be able to run business code encapsulated in your class. In the Zend Framework, several objects provide a toArray method, but that is not always sufficient as sometimes you'd like to keep with the $object->varname syntax.
That is where the Transfer Object arrives. While the preceding definition is not exact (that's not the real purpose of the Transfert Object in the J2EE spirit), This is the most common use that PHP Developers can make of it nowadays I think. So I came up with a very light implementation of a concept which I hope can prove useful for any folks getting by there.
See also:
- Martin Fowler's Value Object and Data Transfer Object
- The Transfert Object as a Core J2EE Pattern