I need static class (object) to store a global variable value. I'm new in PHP but i have experience in other language that have OOP concept like in Java. In Java i can make static variable and can call anywhere i want. But how to do same in PHP?
I use CodeIgniter framework , before i try this i try using session to store but i want to use another way like above. can anyone help me?
Can i do like this ?
static class myClass{
public static myVar = "";
}
Because you mentioned framework Codeigniter and use of session I assume that you need to use this in multiple controller and views. So I there is also another way which works bit different than property of class but more similar than session (except changed value won't affect on another page).
So Use Constant.
Define it in
application > config > constant.php
page. There are many constant defined in that page, using exact same syntax you can define your values and you can use it very easily to any where.
just like if you define SITE_NAME constant in constant.php as
defined('SITE_NAME') OR define('SITE_NAME', "My Example Site");
After that you can use it anywhere in any controller, view or model of your Codeigniter, What you need to do is just echo it
<?php echo SITE_NAME; //only SITE_NAME not $SITE_NAME ?>
I hope it is what you want, if not sorry for my misunderstanding.
You can have a static-like class in PHP. But you don't have an app-cycle in PHP. This means you won't get a real static (or singleton) in your whole application.
If you shouldn't be able to instantiate a class then it should be abstract and define its methods as static. However, somebody could just subclass the class and make it non-abstract. If you don't want that to be a possibility either then the class should be abstract final.
If you do this, you can call methods directly on the class in question with ClassName::methodName() syntax. Do bear in mind that classes written like this can't make use of $this because it is only valid for an object instance. If you need the class to maintain state then you will have to define a static variable and use it with self:: or static:: syntax.
abstract final class SomeClass
{
private static $var = "";
public static function setVar($newVal)
{
self::$var = (string) $newVal;
}
public static function getVar()
{
return self::$var;
}
}
A word of caution on doing this though, use of abstract classes/methods can very easily lead to tightly coupled code which is bad for a number of reasons.
For example, if you write a class that calls the methods of an abstract class directly by any means other than inheriting from the abstract class, then it will be impossible to unit test that class in isolation. It will always require your abstract class to be part of the test suite too, which means it's more difficult to determine whether a test failure has been caused by a fault in the class under test or in the abstract class it's depending on.
What's more, if the abstract class you're depending on serves as an accessor for a data source, then you also will not be able to mock the class during tests. Mocking is a very powerful way of verifying the correctness of a class without having to rely on the environment that the class is running in. for example, you can mock a database access class with a compatible object that always returns the same data from an array instead of hitting an actual database. This means that you can guarantee that when you run a test it will run with data in a state that you have full control over. If you access a database via an abstract class's methods then you can't replace that for testing and suddenly you may end up with a test suite that might succeed or fail depending on the state of the database at the time you run the test. Even worse, if your tests involve writing to the database then you could potentially corrupt your data source when running tests.
