<?php
 
/**
 * the abstract class which represents a nullable box type.
 * 
 * <pre class="brush: php">
 *  $obj = new Midori_Int32(null);
 *  echo $obj; // output will be 0;
 *  if(!$obj->hasValue)
 *  	echo "I am null!";
 * </pre>
 * 
 * @author Michael
 * @package Midori
 * @see get_class()
 * @see function_exists()
 * @property boolean $hasValue Gets whether or not the value is not null.
 * @property-read string $nullReplacementValue; Get the defaulted value for __toString when the value is null.
 */
abstract class Midori_Nullable extends Midori_Object
{
 
	/**
	 * gets the default value that will replace the value 
	 * when __toString() is called. 
	 * 
	 * @ignore
	 * @return string
	 */
	protected function getNullReplacementValue()
	{
		return "";
	}
 
	/**
	 * gets the value 
	 * 
	 * @ignore
	 * @return mixed
	 */
	protected function getValue()
	{
		return $this->get("value");
	}
 
	/**
	 * sets the value
	 * 
	 * @ignore
	 * @param mixed $value
	 * @return void
	 */
	protected function setValue($value)
	{
		$this->set("value", $value);
	}
 
	/**
	 * gets if the object has a value.
	 * 
	 * @ignore
	 * @return boolean
	 */
	protected function getHasValue()
	{
		return ($this->value != null);
	}
 
	/**
	 * 
	 * 
	 * 
	 */
	public function __toString()
	{
		if($this->hasValue)
			return "$this->value";
		return $this->nullReplacementValue;
	}
 
	protected function val($value)
	{
		if($value instanceof Midori_Nullable)
			return $value->value;
		return $value;	
	}
 
}
 
function val($value)
{
	if($value instanceof Midori_Nullable)
		return $value->value;
	return $value;	
}