how do I stop further methods in a PHP class? - php

Question

I am learning OOP with PHP. I am creating a class to extract XML data from a website. My question is how do I stop the given object from executing more methods if there is an error with the first method. For example, I want to send the URL:
class GEOCACHE {
public $url;
public function __construct($url)
{
$this->url=$url;
if (empty($this->url))
{
echo "Missing URL";
}
}
public function secondJob()
{
whatever
}
}
when I write like this:
$map = new GEOCACHE ("");
$map->secondJob("name");
How do I prevent the secondJob method from being executed in that given object without the script terminating?

Answer 1

Throw an Exception in the constructor, therefore the object will never be created
public function __construct($url)
{
$this->url=$url;
if (empty($this->url))
{
throw new Exception("URL is Empty");
}
}
You can then do something like this:
try
{
$map = new GEOCACHE ("");
$map->secondJob("name");
}
catch ( Exception $e)
{
die($e->getMessage());
}

Answer 2

Consider using exceptions in order to control the flow of the script. Throw an exception in the constructor, and catch it outside.

Answer 3

class GEOCACHE {
public $url;
public function __construct($url)
{
$this->url=$url;
if (empty($this->url))
{
throw new Exception("Missing URL");
}
}
public function secondJob()
{
whatever
}
}
try{
$map = new GEOCACHE ("");
$map->secondJob("name");
}catch($e){
// handle error.
}

Answer 4

Throw an exception from __construct
public function __construct($url)
{
if(null == $url || $url == '')
{
throw new Exception('Your Message');
{
}
then in your code
try
{
$geocache = new Geocache($url);
$geocache->secondJob();
// other stuff
}
catch (exception $e)
{
// logic to perform if the geocode object fails
}