Support-Groups/admin/helpers/negativefinder.php

<?php
/**
* 
* 	@version 	1.0.0
* 	@package 	Detecting negative numbers
* 	@license	GNU General Public License <http://www.gnu.org/copyleft/gpl.html>
*
**/

// No direct access.
defined('_JEXEC') or die;

/**
*	Detecting negative numbers
**/

class SupportgroupsExpression
{
	protected $expression;
	protected $result;

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

	public function evaluate()
	{
		$this->result = eval("return ".$this->expression.";");
		return $this;
	}

	public function getResult()
	{
		return $this->result;
	}
}

class SupportgroupsNegativeFinder
{
	protected $expressionObj;

	public function __construct(SupportgroupsExpression $expressionObj)
	{
		$this->expressionObj = $expressionObj;
	}


	public function isItNegative()
	{
		$result = $this->expressionObj->evaluate()->getResult();
		
		if($this->hasMinusSign($result))
		{
			return true;
		}
		else
		{
			return false;
		}
	}

	protected function hasMinusSign($value) 
	{
		return (substr(strval($value), 0, 1) == "-");
	}
}