PHP Builder Pattern Example

builder.php

<?php
/**
 * An extremely basic class for creating people objects
 */
class Person
{
    public $employed;
 
    public $gender;
 
    const GENDER_MALE   = "Male";
 
    const GENDER_FEMALE = "Female";
 
}
 
/**
 * All people builder should implement this interface
 */
interface PersonBuilderInterface
{
    public function setGender();
    public function setEmployed();
    public function getResult();
}
 
/**
 * builder to create an employed male
 */
class EmployedMaleBuilder implements PersonBuilderInterface
{
    private $person;
 
    public function __construct()
    {
        $this->person = new Person();
    }
 
    public function setGender()
    {
        $this->person->gender = Person::GENDER_MALE;
    }
 
    public function setEmployed()
    {
        $this->person->employed = true;
    }
 
    public function getResult()
    {
        return $this->person;
    }
}
 
/**
 * builder to create an unemployed male
 */
class UnemployedMaleBuilder implements PersonBuilderInterface
{
    private $person;
 
    public function __construct()
    {
        $this->person = new Person();
    }
 
 
    public function setGender()
    {
        $this->person->gender = Person::GENDER_MALE;
    }
 
    public function setEmployed()
    {
        $this->person->employed = false;
    }
 
    public function getResult()
    {
        return $this->person;
    }
}
 
/**
 * builder to create an employed female
 */
class EmployedFemaleBuilder implements PersonBuilderInterface
{
    private $person;
 
    public function __construct()
    {
        $this->person = new Person();
    }
 
    public function setGender()
    {
        $this->person->gender = Person::GENDER_FEMALE;
    }
 
    public function setEmployed()
    {
        $this->person->employed = true;
    }
 
    public function getResult()
    {
        return $this->person;
    }
}
 
/**
 * builder to create an unemployed female
 */
class UnemployedFemaleBuilder implements PersonBuilderInterface
{
    private $person;
 
    public function __construct()
    {
        $this->person = new Person();
    }
 
    public function setGender()
    {
        $this->person->gender = Person::GENDER_FEMALE;
    }
 
    public function setEmployed()
    {
        $this->person->employed = false;
    }
 
    public function getResult()
    {
        return $this->person;
    }
}
 
/**
 * The director class is part of the builder patter, the build method should be passed a builder.
 * The build method should than call all of the builder methods and return a Person object
 */
class PersonDirector
{
    public function build(PersonBuilderInterface $builder)
    {
        $builder->setGender();
        $builder->setEmployed();
 
        return $builder->getResult();
    }
}
 
$director                = new PersonDirector();
$employedMaleBuilder     = new EmployedMaleBuilder();
$unemployedMaleBuilder   = new UnemployedMaleBuilder();
$employedFemaleBuilder   = new EmployedFemaleBuilder();
$unemployedFemaleBuilder = new UnemployedFemaleBuilder();
 
/**
 * object(Person)#3 (2) {
 * (
 *   ["employed"] => bool(true)
 *   ["gender"] => string(4) "Male"
 * )
 */
$employedMale     = $director->build($employedMaleBuilder);
 
/**
 * object(Person)#5 (2) {
 * (
 *   ["employed"] => bool(false)
 *   ["gender"] => string(4) "Male"
 * )
 */
$unemployedMale   = $director->build($unemployedMaleBuilder);
 
/**
 * object(Person)#7 (2) {
 * (
 *   ["employed"] => bool(true)
 *   ["gender"] => string(4) "Female"
 * )
 */
$employedFemale   = $director->build($employedFemaleBuilder);
 
/**
 * object(Person)#11 (2) {
 * (
 *   ["employed"] => bool(false)
 *   ["gender"] => string(4) "Female"
 * )
 */
$unemployedFemale = $director->build($unemployedFemaleBuilder);

What if a builder needs external data?

For instance, the result should be a Person object with a birthdate. For employers, it also requires a date when the person hired and department. And for unemployed – a date when this person fired.