PHP - Countable

php_countable.php

<?php
/**
 * Class EmployeesCollection
 */
class EmployeesCollection implements Countable
{
    
    protected $employees = array();

    /**
     * Count elements of an object
     * @link http://php.net/manual/en/countable.count.php
     * @return int The custom count as an integer.
     * </p>
     * <p>
     * The return value is cast to an integer.
     * @since 5.1.0
     */
    public function count()
    {

        return count($this->employees);
    }

    /**
     * @param Employee $employee
     */
    public function addEmployee(\Employee $employee)
    {

        $this->employees[] = $employee;
    }
}

/**
 * Class Employee
 */
class Employee
{

    protected $id;

    /**
     * @return mixed
     */
    public function getId()
    {

        return $this->id;
    }

    /**
     * @param mixed $id
     */
    public function setId($id)
    {

        $this->id = $id;
    }
}

$employeesCollection = new EmployeesCollection();
for ($i = 1; $i < 51; $i++) {
    $employee = new Employee();
    $employee->setId($i);
    $employeesCollection->addEmployee($employee);
}

print_r($employeesCollection->count());

// Output:
// 50