I have a class with methods, some of these methods use the same variable across board - "$company_id". Now, I don't want to explicitly define what is contained in $company_id for every method. I want to define it once in a constructor and then reference it in my methods. Please how do I do this? This is how it looks currently.
public function __construct(){
//what should I do here?
}
public static function getItemLimit(){
$company_id = Auth::user()->company_id;
$item_limit = Company::where('id', $company_id)->count();
return $item_limit;
}
public static function currentItemCount(){
$company_id = Auth::user()->company_id;
$item_count = Item::where('company_id', $company_id)->count();
return $item_count;
}
Try this Use Company_Id instead of $abcVar
class Abc{
public static $abcVar = '';
public function __construct()
{
self::$abcVar = 11;
}
public static function getItemLimit()
{
echo self::$abcVar;
exit;
}
}
$obj = new Abc();
Abc::getItemLimit();
Related
I have a function declared in another file. I need to get a variable from it and use it in the class. But for some reason an error appears.
$myvar = myfunc($text);//an error here
class func{
public $title = $myvar;//and here
public function ($title){
...
}
}
You can inject the return value of the function in the constructor when the object is being initialized.
include_once 'func.php';
class Myclass{
public $title;
function __construct( $title = null )
{
$this->title = $title;
}
}
$obj = new Myclass( getVar() );
echo $obj->title;
func.php class
<?php
function getVar()
{
return 'this_var';
}
?>
Your question is about how to use a variable inside a class
class MyClass{
public $title; //do not put a variable here, this is invalid
///you could set a default like this
// e.g. public $title = "Jam";
//this is a setter
public function setTitle(string $title){
$this->title = $title
}
public function getTitle() {
return $this->title;
}
}
then use
$class = new MyClass();
$class->setTitle("jam sponge");
echo $class->getTitle();
or
define a constructor
class MyClass{
public $title;
//this is a constructor
public function __construct(string $title){
$this->title = $title
}
public function getTitle() {
return $this->title;
}
}
then use
$class = new MyClass("jam sponge");
echo $class->getTitle();
the latter is my preference.
As for this $myvar = myfunc($text);//an error here that's not relate to passing the var to the class. You have some other issue in that function, so either show that code or post anew question specific to it
I am trying to understand how to efficiently create a new class object and set the variables directly.
I have a class:
class element_model
{
public $sType;
public $properties;
}
I have a controller in which the following function is defined:
public function create_element($sType, $properties)
{
$oElement_model = new element_model($sType, $properties);
return new element_model($sType, $properties);
}
But this does not returns a new element_model with properties set, it just returns an empty object.
It does not, however, throw an error.
What is the reason the function above does not work?
You have to pass to the constructor of the class, in PHP you should have a method in the class __construct :
class element_model
{
public $sType;
public $properties;
public function __construct($type, $property)
{
$this->sType = $type;
$this->properties = $property;
}
}
Then you can access them (note the variables are public)
$elem = new element_model($sType, $properties);
$elem->sType;
Although in some cases it is better to encapsulate vars (declare them private):
class element_model
{
private $sType;
private $properties;
public function __construct($type, $property)
{
$this->sType = $type;
$this->properties = $property;
}
public function getType()
{
return $this->sType;
}
public function getProperty()
{
return $this->properties;
}
}
Then you can access the variable through a getter
$elem = new element_model($sType, $properties);
$elem->getType(); //and
$elem->getProperty();
You must create a __construct function in your class that accepts the parameters and sets your variables. Like this:
class element_model{
.
.
.
public function __construct($type,$properties)
{
$this->sType = $type;
$this->properties = $properties;
}
}
The __construct function will be called when you create the object.
But if you want to be extra cool in programming, just define your properties as private and create getter and setter functions to access the variables of your object
private $sType;
public function getSType(){
return $this->sType;
}
public function setSType($value){
$this->sType = $value;
}
If I have a setter and getter methods below :
<?php
class Name{
protected $first ;
public function setNameType($value) {
$this->first = $value;
}
public function getNameType() {
return $this->first;
}
}
$name = new Name;
$name->setNameType("My Name");
echo $name->getNameType();
?>
and a construct method like this
<?php
class Name{
protected $first ;
public function __construct($value) {
$this->first = $value;
}
public function getNameType() {
return $this->first;
}
}
$name = new Name("My Name");
echo $name->getNameType();
?>
Can I use the two interchangeably at all times or is there situations where one will be most prefered over the other ?
There is also some great explaination about your question: http://www.potstuck.com/2009/01/08/php-dependency-injection/
Try this website. It explains all with examples.
http://ralphschindler.com/2012/03/09/php-constructor-best-practices-and-the-prototype-pattern
Generally you would use constructors to set values if your class cannot exist or doesn't make sense without the value. If the value is allowed to be changed, than add a setter. If it should never be changed after construction, then don't add a setter.
An example code:
class Book {
public function __construct() {
$registry = RegistrySingleton::getInstance();
$this->_database = $registry->database;
// or
global $databaseConnection;
$this->_database = $database;
}
}
class Book {
private $_databaseConnection;
public function __construct() { }
public function setDatabaseConnection($databaseConnection) {
$this->_databaseConnection = $databaseConnection;
}
}
$book = new Book();
$book->setDatabase($databaseConnection);
$book = new Book($databaseConnection, $configFile);
$book = new Book();
$book->setDatabase($databaseConnection);
$book->setConfigFile($configFile);
class Container {
public static $_database;
public static function makeBook() {
$book = new Book();
$book->setDatabase(self::$_database);
// more injection...
return $book;
}
}
And then:
$book = Container::makeBook();
How can I figure out in what class a reference to a variable was initiated (and currently exists)?
Example:
<?php
class MyClass {
public $array = array(
"this",
"is",
"an",
"array"
);
}
$class = new MyClass();
$arrayReference = &$class->array;
GetClassForVariable($arrayReference); //Should return "MyClass"
?>
My best bet is some kind of Reflection, but I haven't found any functions that seem suitable for this.
Edit:
A better suited example for what I want is the following:
<?php
class API_Module {
public $module;
public $name;
private $methods = array();
public function __construct($module, $name) {
$this->module = $module;
$this->name = $name;
$this->methods["login"] = new API_Method($this, "login", "Login");
}
public function GetMethod($method) {
return $this->methods[$method];
}
public function GetURL() {
return $this->module; //Should return "session"
}
}
class API_Method {
public $method;
public $name;
private $parentReference;
private $variables = array();
public function __construct(&$parentReference, $method, $name) {
$this->parentReference = $parentReference;
$this->method = $method;
$this->name = $name;
$this->variables["myvar"] = new API_Variable($this, "myvar");
}
public function GetURL() {
return $this->GetParentURL() . "/" . $this->method; //Should return "session/login"
}
public function GetVariable($variableName) {
return $this->variables[$variableName];
}
private function GetParentURL() {
// Need to reference the class parent here
return $this->parentReference->GetURL();
}
}
class API_Variable {
public $name;
private $parentReference;
public function __construct(&$parentReference, $name) {
$this->parentReference = $parentReference;
$this->name = $name;
}
public function GetURL() {
return $this->GetParentURL() . "/" . $this->name; //Should return "session/login/myvar"
}
private function GetParentURL() {
// Need to reference the class parent here
return $this->parentReference->GetURL();
}
}
$sessionModule = new API_Module("session", "Session");
var_dump($sessionModule->GetMethod("login")->GetVariable("myvar")->GetURL()); //Should return "session/login/myvar"
?>
Now, this works fine, but I'd love to be able to do this without using $parentReference in every single subvariable. It might not be possible, but I'd love to know whether it is or not.
For your example:
$class = new MyClass();
$arrayReference = &$class->array;
GetClassForVariable($arrayReference); //Should return "MyClass"
to find out to which variable originally the alias $arrayReference refers to is not possible in PHP. There is no function available resolving the aliases.
Additionally $class->array is just a variable on it's own. So you would also need to find out based on a value in which class it was defined. That is not possible as well, similar to that PHP does not offer anything to resolve a variable alias, it also does not offer anything to learn about the definition of a variable.
So in short PHP does not have a ReflectionVariable class available ;) I wonder if it is even possible.
The get_class() function should work:
http://php.net/manual/en/function.get-class.php
I agree with GRoNGoR that you shouldn't need to get the parent class of a property of an instantiated object. You could instead just get the name of the class before accessing the property. For example:
$class = new MyClass();
$parent_class = get_class($class); // returns "MyClass"
$arrayReference = &$class->array;
Not sure why you'd need the parent class of the property when you have the object instance and can easily get the parent class from there.
I've never worked before with polymorphism. I just heard about it when this question came up.
I have a little backend with 2 permissions. Admin/Normal User. Depending on the permission, i want to display a different navigation, less or more options on the forms etc. But i don't want to create a form for each permission but rather disable the elements i don't need etc.
How would i go with that?
At the moment, i'm using something like that: (Which isn't really polymorphism)
<?php
class My_Resources_ResourceLoader extends Zend_Application_Resource_ResourceAbstract {
public $templateForm = null;
public $customerForm = null;
function init() {
$permission = 'admind';
if($permission == 'admin') {
$this->templateForm = new Application_Form_newTemplate;
} else {
$form = new Application_Form_newTemplate;
$form->removeElement('newTemplate_customer');
$this->templateForm = $form;
}
return $this;
}
}
And in my controller e.g.
<?php
$bootstrap = $this->getInvokeArg('bootstrap');
$xx = $bootstrap->getResource('ResourceLoader');
$this->view->test = $xx->templateForm;
The roles never gonna change. This will probably be okay but isn't the very best solution. What would be a better approach to this?
I've thrown away the approach above and now use real polymorphism like this:
at Application/Model got an interface like:
And 2 Classes like:
<?php
class Application_Model_TemplateUser implements Application_Model_TemplateInterface {
private $table = null;
private $row = null;
private $id = null;
private $formValues = null;
function __construct() {}
public function exist() {}
public function save() {}
public function getCustomerId($name) {}
public function update() {}
public function getForm() {
$form = new Application_Form_newTemplate;
$form->removeElement('newTemplate_customer');
return $form;
}
}
And
<?php
class Application_Model_TemplateAdmin implements Application_Model_TemplateInterface {
private $table = null;
private $row = null;
private $id = null;
private $formValues = null;
function __construct() {}
public function exist() {}
public function save() {}
public function getCustomerId($name) {}
public function update() {}
public function getForm() {
return new Application_Form_NewTemplate();
}
}
In my Controller i do:
<?php
$permission = 'User'; //TODO: Get from Session
$class = 'Application_Model_Template' . $permission;
$xx = new $class;
$form = $xx->getForm();
$this->view->test = $form;
This are just examples. But i think like that I'm really on a better way. Maybe i'm going to use abstract classes since i'm using Zend_Db-Table_Row, which is always the same for updating a row, so it would make more sense using a abstract class instead of an interface.
Nice article about Polymorphism in PHP: http://net.tutsplus.com/tutorials/php/understanding-and-applying-polymorphism-in-php/