组合模式-PHP

• 标准例子
• 员工类型

标准例子

组合模式的标准例子。

<?php

// component为组合中的对象接口，在适当的情况下，实现所有类共有接口的默认行为。声明一个接口用于访问和管理Component的字部件。
abstract class Component {
    protected $name;

    function __construct($name) {
        $this->name = $name;
    }

    // 通常用add和remove方法来提供增加或移除树枝或树叶的功能
    abstract public function add(Component $c);
    abstract public function remove(Component $c);
    abstract public function display($depth);
}

// leaf在组合中表示叶子节点对象，叶节点对象没有子节点
class Leaf extends Component {
    // 由于叶子没有再增加分枝和树叶，所以add和remove方法实现它没有意义
    // 但这样做可以消除叶节点和枝节点在抽象层次的区别，他们具有完全一致的接口
    public function add(Component $c) {
        echo "can not add to a leaf\n";
    }

    public function remove(Component $c) {
        echo "can not remove to a leaf\n";
    }

    // 叶节点的具体方法，此处是显示其名称和级别
    public function display($depth) {
        echo str_repeat('-', $depth).$this->name."<br />";
    }
}

//composite定义有枝节点行为，用来存储子部件，在Component接口中实现与子部件有关的操作，比如增加add和删除remove.
class Composite extends Component
{
    //一个子对象集合用来存储其下属的枝节点和叶节点。
    private $childern = [];

    public function add(Component $c)
    {
        array_push($this->childern, $c);
    }

    public function remove(Component $c)
    {
        foreach ($this->childern as $key => $value) {
            if ($c === $value) {
                unset($this->childern[$key]);
            }
        }
    }

    // 显示其枝节点名称，并对其下级进行遍历
    public function display($depth)
    {
        echo str_repeat('-', $depth).$this->name."<br />";
        foreach ($this->childern as $component) {
            $component->display($depth + 2);
        }
    }
}

//客户端

$root = new Composite('root');
$root->add(new Leaf("Leaf A"));
$root->add(new Leaf("Leaf B"));

$comp = new Composite("Composite X");
$comp->add(new Leaf("Leaf XA"));
$comp->add(new Leaf("Leaf XB"));

$root->add($comp);

$comp2 = new Composite("Composite X");
$comp2->add(new Leaf("Leaf XA"));
$comp2->add(new Leaf("Leaf XB"));

$comp->add($comp2);

$root->add(new Leaf("Leaf C"));

$leaf = new Leaf("Leaf D");
$root->add($leaf);
$root->remove($leaf);

$root->display(1);
// 输出
// -root
// ---Leaf A
// ---Leaf B
// ---Composite X
// -----Leaf XA
// -----Leaf XB
// -----Composite X
// -------Leaf XA
// -------Leaf XB
// ---Leaf C

员工类型

公司有不同职位员工，他们虽然工作的内容不同，但是他们拥有一些相同的信息，例如都有薪资信息、姓名信息等。他们共同组成了公司的组织架构。

<?php

interface Employee {
  public function __construct(string $name, float $salary);
  public function getName(): string;
  public function setSalary(float $salary);
  public function getSalary(): float;
  public function getRoles(): array;
}

class Developer implements Employee {
  protected $salary;
  protected $name;
  protected $roles;

  public function __construct(string $name, float $salary) {
    $this->name = $name;
    $this->salary = $salary;
  }

  public function getName(): string {
    return $this->name;
  }

  public function setSalary(float $salary) {
    $this->salary = $salary;
  }

  public function getSalary(): float {
    return $this->salary;
  }

  public function getRoles(): array {
    return $this->roles;
  }
}

class Designer implements Employee {
  protected $salary;
  protected $name;
  protected $roles;

  public function __construct(string $name, float $salary) {
    $this->name = $name;
    $this->salary = $salary;
  }

  public function getName(): string {
    return $this->name;
  }

  public function setSalary(float $salary) {
    $this->salary = $salary;
  }

  public function getSalary(): float {
    return $this->salary;
  }

  public function getRoles(): array {
    return $this->roles;
  }
}

class Organization {
  protected $employees;

  public function addEmployee(Employee $employee) {
    $this->employees[] = $employee;
  }

  public function getNetSalaries(): float {
    $netSalary = 0;

    foreach($this->employees as $employee) {
      $netSalary += $employee->getSalary();
    }

    return $netSalary;
  }
}

// client
// Prepare the employees
$john = new Developer('John Doe', 12000);
$jane = new Developer('Jane Doe', 15000);

// Add them to organization
$organization = new Organization();
$organization->addEmployee($john);
$organization->addEmployee($jane);

echo "Net salaries: " . $organization->getNetSalaries(); // Net Salaries: 27000