exception $e->getPrevious()->getMessage()

<?php
//example03.php
/**
    小例子 验证变量check if the name contains only letters, 
        and does not contain the word name*/
    $name = "Name";
    try
    {
        try  
        { 
            //preg_match() 返回 pattern  的匹配次数。 
            //它的值将是0次（不匹配）或1次，因为 preg_match() 在第一次匹配后 将会停止搜索。 
            //preg_match_all() 不同于此，它会一直搜索 subject  直到到达结尾。 
            //如果发生错误 preg_match() 返回 FALSE 。                
            if(preg_match('/[^a-z]/i', $name))
            {
                throw new Exception("$name contains character other than a-z A-Z");
            }
            if(strpos(strtolower($name), 'name') !== false)
            {
                throw new Exception("$name contains the word name");
            }
            echo "The Name is valid";
        }
        catch (exception $e)
        {
            throw new Exception("insert name again", 0, $e);
        }
    }
    catch (exception $e)
    {
        if($e->getPrevious())
        {
            echo "The Previous Exception is: " . $e->getPrevious()->getMessage() . "<br/>";
        }
        echo "The Exception is: " . $e->getMessage() . "<br/>";
    }

/*
The Previous Exception is: Name contains the word name
The Exception is: insert name again
*/