How to get object value from another object [closed] - php

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It's been a while since I last work with object. I can't figure out what I did wrong. I have a class that contain another class as a property. After instantiating ItemDetail() inside Item(), I can't get the value of description. var_dump($item) give me NULL for the value of $detail. Please help. Thank you.
<?php
class Item
{
private $name;
private $detail;
function __construct() {
$this->name = 'some name';
$this->detail = new ItemDetail();
}
function getDetail() {
return $this->detail;
}
}
class ItemDetail
{
private $description;
function __construct() {
$this->description = 'some description';
}
function getDescription {
return $this->description;
}
}
$item = new Item();
echo $item->getDetail()->getDescription();
//var_dump($item);
?>

You need to change the scope of your class properties, or define a method that returns the values. Example:
class Item
{
private $name;
private $detail;
function __construct() {
$this->name = 'some name';
$this->detail = new ItemDetail();
}
public function getDescription() {
return $this->detail->getDescription();
}
}
class ItemDetail
{
private $description;
function __construct() {
$this->description = 'some description';
}
public function getDescription() {
return $this->description;
}
}
$item = new Item();
echo $item->getDescription();
If you make your properties public, you can get them like this as well:
class Item
{
public $name;
public $detail;
public function __construct() {
$this->name = 'some name';
$this->detail = new ItemDetail();
}
}
class ItemDetail
{
public $description;
public function __construct() {
$this->description = 'some description';
}
}
$item = new Item();
echo $item->detail->description;
It's all about visibility

Related

how cann I convert php class to json [closed]

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I am trying to convert a simple class object to json as string.
It does not work!. could you help me please.
here are my files:
Peson.php
<?php
class Person
{
private $name;
public function getName()
{
return $this->name;
}
public function setName($name)
{
$this->name = $name;
}
public function toJson()
{
return json_encode($this);
}
}
?>
index.php
include 'Person.php';
$person = new Person();
$person->setName("John");
echo $person->toJson();
Result :
You're getting an empty object because your class doesn't have any public properties to encode. Change name from private to public and you'll get output like this: {"name":"John"}
You can use get_object_vars for this.
public function toJson()
{
return json_encode(get_object_vars($this)); //returns {"name":"stringNameHere"}
}
More info about get_object_vars here.
This is how your code would look:
class Person
{
private $name;
public function getName()
{
return $this->name;
}
public function setName($name)
{
$this->name = $name;
}
public function toJson()
{
return json_encode(get_object_vars($this));
}
}
$person = new Person();
$person->setName('testName');
echo $person->toJson(); //Print {"name":"testName"}
Here you have a live code example
In this case you get an empty object because the properties are private. A way to keep your properties private and still geting their values in a JSON is using the JsonSerializable Interface. Then implementing its method jsonSerialize().
class Person implements JsonSerializable
{
private $name;
public function getName()
{
return $this->name;
}
public function setName($name)
{
$this->name = $name;
}
public function jsonSerialize()
{
$vars = get_object_vars($this);
return $vars;
}
}
<?php
class Person implements \JsonSerializable
{
private $name;
public function getName()
{
return $this->name;
}
public function setName($name)
{
$this->name = $name;
}
public function jsonSerialize()
{
return get_object_vars($this);
}
}
?>
then, you can convert your person object to JSON with json_encode
$person = new Person();
$person->setName("John");
echo json_encode($person);

echo OOP php method [closed]

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I had one lesson in OOP which included messaging between classes. On the tutorial, the guy just showed var_dump output version of that. I wanted to play with the code and change from var_dump to echo output, because it would me more useful in future. I just couldn't find any solution so you guys are my only option. Here's the code.
<?php
class Person {
protected $name;
public function __construct($name)
{
$this->name = $name;
}
public function getName()
{
return $this->name;
}
}
class Business {
// adding Staff class to Business
public function __construct(Staff $staff)
{
$this->staff = $staff;
}
// manual hire(adding Person to Staff)
public function hire(Person $person)
{
// add to staff
$this->staff->add($person);
}
// fetch members
public function getStaffMembers()
{
return $this->staff->members();
}
}
class Staff {
// adding people from Person class to "member" variable
protected $members = [];
public function __construct($members = [])
{
$this->members = $members;
}
// adding person to members
public function add(Person $person)
{
$this->members[] = $person;
}
public function members()
{
return $this->members;
}
}
// you can also create an array with this method
$bros = [
'Bro',
'Zdenko',
'Miljan',
'Kesten'
];
// pretty simple to understand this part
$employees = new Person([$bros]);
$staff = new Staff([$employees]);
$business = new Business($staff);
var_dump($business->getStaffMembers());
// or the print_r, it doesn't matter
print_r($business->getStaffMembers());
?>
Try to loop through the array and echo out every single value.
$array = $something //your assignment here
foreach($array as $key => $value ){
echo "$key => $value\n";
}

Pass a class as parameter

I am trying to pass a class as a parameter but I do not know if it is possible.
class User {
var $name;
}
class UserRepository {
private $type;
public function __construct(Class) {
$this->type = Class;
}
public function getInstance() {
return new $this->type;
}
}
$obj = new UserRepository(User);
I am accepting suggestions on other ways to do it as well.
Just instantiate the class and call that
$user = new User();
$obj = new UserRepository($user);
Another option (since User contains only variables) is to make the variable static and use that
class User {
public static $name;
}
$obj = new UserRepository(User::$name);
I think you are just looking for a string:
class User {
var $name;
}
class UserRepository {
private $type;
public function __construct($Class) {
^^^^^^ this will be a string
$this->type = $Class;
}
public function getInstance() {
return new $this->type;
}
}
$obj = new UserRepository('User');
^^^^^^ send a string here
var_dump($obj->getInstance());
output:
object(User)#2 (1) { ["name"]=> NULL }
An example.

understanding dependency injection in PHP

class Author {
private $firstName;
private $lastName;
public function __construct($firstName, $lastName) {
$this->firstName = $firstName;
$this->lastName = $lastName;
}
public function getFirstName() {
return $this->firstName;
}
public function getLastName() {
return $this->lastName;
}
}
class Question {
private $author;
private $question;
public function __construct($question, Author $author) {
$this->author = $author;
$this->question = $question;
}
public function getAuthor() {
return $this->author;
}
public function getQuestion() {
return $this->question;
}
}
Class author is injected into the constructor of Question class am I correct? but how to call the Question class to get the author's name?
$question = new Question('What is PHP', 'Adam');
$question->getFirstname;
like this? I assume Question class inherited Author class so Question's instance can use the function of Author Class?
Simple
echo $question->getAuthor()->getFirstName();
Think of it this way if it helps
$author = $question->getAuthor();
echo $author->getFirstName();
Also note that you can't construct a Question with the string "Adam", you need to pass an instance of Author
$question = new Question('What is PHP', new Author('Adam', 'Lastname'));
You could create a new method:
class Question
{
// ...
function getAuthorFirstname()
{
return $this->author->getFirstname();
}
}
$question = new Question(.., new Author(..., ...));
echo $question->getAuthorFirstname();
Or, if you don't really care about Law of Demeter or feel that it doesn't apply:
$question = new Question(.., new Author(..., ...));
echo $question->getAuthor()->getFirstname();
In the end it all comes down to striking a balance between information hiding and pragmatism.

OOP - How to define what object create? [closed]

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I ask your advise.
In my php file there are some classes.
class Template {
public $id;
public $title;
public $text;
public $description;
public $data = array();
public $content_html;
public $width_content = 500;
public $type;
public $time;
public $user;
public $category;
protected $CI;
// The next code works for a one element of array $data
function __construct($data = array()){
$this->title = $data['title'];
$this->text = $data['text'];
$this->category = $data['category'];
$this->type = $data['type'];
$this->time = $data['time'];
$this->CI =& get_instance();
$this->user = new InformationUser($data);
}
class Articles extends Template {
}
class News extends Template {
}
class Init {
public $posts = array('type' => 2);
}
The start point of my classes is a class Init.
Inside this class there is array of users posts.
In each element array there is a type value, which define what object class I must create.
For example:
class Init {
function define(){
foreach($this->posts as $val){
if($val['type'] == 2){
$article = new Articles($val);
//TODO $articles
} else if($val['type'] == 3){
$news = new News($val);
//TODO $news
}
}
}
}
I know that is variant is wrong, better to put all array posts() to class. But I can not do this.
I need, that for different type of element of array - to work separate class (for news - News class, article - class Article etc.)
What do you advise me?
From the minimal info provided.. I assume you are looking for something like this:
<?php
class Init {
public static function define($type, $text)
{
switch($type) {
case 1:
return new Articles($text);
break;
case 2:
return new News($text);
break;
default:
throw new Exception('Undefined type');
}
}
}
// $template = Init::define(1, 'article text');
// $template = Init::define(2, 'news text');

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