EnumeratedType.php

<?php

/**
 * 
 * @example
 * <?php
 *  
 * class Day extends EnumeratedType 
 * {
 *     const MONDAY = 'Monday';
 *     const TUEASDAY = 'Tuesday';
 *     const WEDENESDAY = 'Wednesday';
 *     const THURSDAY = 'Thursday';
 *     const FRIDAY = 'Friday';
 *     const SATURDAY = 'Saturday';
 *     const SUNDAY = 'Sunday';
 * }
 * 
 * $day = new Day(Day::MONDAY);
 * assert($day->is(Day::MONDAY), 'Created day is Monday');
 * 
 * class FavouriteColor extends EnumeratedType {
 *     
 *     const GREEN = 9001;
 *     const BLUE = 9002;
 *     const YELLOW = 9003;
 *     const PINK = 9004;
 *     
 *     const _DEFAULT = self::PINK;
 * }
 * 
 */
abstract class EnumeratedType 
{
    const _DEFAULT = '';
    
    /** @var string|int */
    protected $value;
    
    /**
     * @param string|int $value
     */
    final public function __constuct($value=null) 
    {
        $this->value = $value === null ? static::_DEFAULT : $value;
        
        if (!$this->hasValue($value)) {
            throw new \InvalidArgumentException('Trying to construct object '.static::class.' with undeclared value');
        }
    }
    
    /**
     * @param string|int $value
     * @return bool
     */
    public function is($value)
    {
        return $this->value == $value;
    }
    
    /**
     * @return string|int
     */
    public function getValue()
    {
        return $this->value;
    }
    
    /**
     * @return string
     */
    public function __toString()
    {
        return (string)$this->value;
    }
    
    /** @var array */
    private static $constants = [];
    
    /**
     * @return bool
     */
    private function hasValue($value)
    {
        $className = static::class;
        if (!isset(self::$constants[$className])) {
            $reflection = new \ReflectionClass($className);
            self::$constants[$className] = $reflection->getConstants();
        }
        return in_array(self::$constants[$className], $value);
    }
}