call another class's function inside a class

Question

i have 2 classes

1. for DB
2. for language

i want to use my language things in the DB so it outputs the result

ex :

class db_control{

        var $db_connection, $lang_var;
        //create the function for the connection
        function db_connect(){
            //define some variables
            global $db_host, $db_username, $db_password, $db_name, $lang_var;
            $this->db_connection = mysql_connect("$db_host","$db_username","$db_password")or die("can't connect to server with these informations");
            //checl that the connection is established
            if($this->db_connection){
                echo $lang_vars->getvar("$langvals[lang_con_est]");
            }

but this

$lang_vars->getvar("$langvals[lang_con_est]");

doesn't work i mean it outputs many problems and am sure my problem is that i didn't define my variables and classes correctly

P.S : the language class is in file called language.php and this part is in DB.MySQL.php

EDIT : this is the language class

class lang_vars{
    public static function getvar($variable){
        return $variable;
    }
}

i want the DB class to display text from the language class thats why i used

 echo $lang_vars->getvar("$langvals[lang_con_est]");

but it doesn't work cuz when i declare the language class $lang_vars = new lang_vars; inside the db_control it shows error unexpected T_something expected T_Function and when i declare it outside nothing up hope i made things more clear now

Answer 1

Any reason why you are still using PHP4 syntax?

When creating an instance of the db_control class, pass the object to be stored as $lan_var into the constructor or set it via a dedicated setter. See Dependency Injection.

class DBControl
{
    protected $_lang;
    public function __construct($lang = NULL)
    {
        if($lang !== NULL) {
            $this->_lang = $_lang;
        }
    }
    public function setLang($lang)
    {
        $this->_lang = $lang;
    }
}

Then do either

$dbControl = new DBControl(new LangThing);

or

$dbControl = new DBControl;
$dbControl->setLang(new LangThing);

Also, get rid of the globals. Pass those in via Dependency Injection too.

Answer 2

Make your language class methods static . Read more here.

class LangClass
{
    public static function getvar()
    {
        // your code here
    }
}

Then, you can use its functions without creating objects like this:

  $LangClass::getvar("$langvals[lang_con_est]");

Answer 3

This can do the trick.

$lang_vars = new LanguageClassOrWhateverItIsCalled();
$lang_vars->getvar($langvals[lang_con_est]);

But maybe you should think of making it a static method. In that case you can call it with:

LanguageClassOrWhateverItIsCalled::getVar($langvals[lang_con_est]);

You can define the method static like:

public static function getVar() {
    // Do something
}

Edit: @SAFAD

You should use the static method for this. To make this work, be sure your class language.php is loaded. To do so just add in the DB.MYSQL.php file the following line:

require_once('language.php');

class db_control {
    ...

Make sure you have the right path to the language.php file.

Then you should call the method in db_control class like this:

if($this->db_connection){
    echo lang_vars::getvar("$langvals[lang_con_est]");
}

Besides, what is the use of a function like this? You should either do:

if($this->db_connection){
    echo $langvals[lang_con_est];
}

or change your static getvar method to:

public static function getvar($variable){
    return $langvals[$variable];
}

and your function call to:

if($this->db_connection){
    echo lang_vars::getvar("lang_con_est");
}