Domain-Driven Design in PHP

Specification Pattern

A common implementation for the criterion object is the Specification pattern. A specification is a simple predicate that takes a Domain object and returns a boolean. Given a Domain object, it will return true if it specifies the specification, and false otherwise:

interface PostSpecification{    /**     * @return boolean     */    public function specifies(Post $aPost);}

We just need to add a query method to our Repository:

interface PostRepository{    // ...    public function query($specification);}