PHP OOP using setter and getter methods on form elements - php

Question

I'm coming from Java programming and I know a little when it comes with PHP OOP style. In Java Server Faces I got used with setters and getters which I use to set values of fields from data entered on form.
So for instance,
Person.java
Class Person{
private String firstname;
public setFirstName(String aFirstName){
this.firstname = aFirstName;
}
public getFirstName(){
return this.firstname;
}
}
PersonForm.xhtml
First Name: <input type="text" name="firstname" value="#{person.firstname}"/>
#{person.firstname} is what calls the setFirstName(); method from the class Person
So I did some google to see how it's done in PHPs OOP style.
So on PHP I thought it would look something like this.
Person.php
class Person{
private $firstname;
public function setFirstName($aFirstName){
$this->firstname = $aFirstName;
}
public function getFirstName(){
return $this->firstname;
}
}
PersonForm.php
<?php
$person = new $Person();
?>
<form>
First Name: <input type="text" name="firstname" value="<?php echo $person->firstname ?>"/>
</form>
I want to store the value entered on input text field using the setFirstName() method of Person class.
Does writing the value="<?php echo $person->firstname ?>" call the setFirstName() method?
Or should I do value="<?php echo $person->setFirstName() ?>"?
I'd appreciate any explanation or example.
PHPs OOP style is very similar with Java that's why I decided to study PHP using the OOP style instead of procedural.
Thank you.

Answer 1

Does writing the value="<?php echo $person->firstname ?>" call the setFirstName() method?
$firstname is a private property of Person class, so you can't access it outside of the class like that. And no, it won't call setFirstName() method.
Or should I do value="<?php echo $person->setFirstName() ?>"?
No, this will give you error since setFirstName() method is expecting an argument with the method call i.e. you're not passing any argument in this method, like $person->setFirstName('My first name'). Having said that, even though you do this, still you won't be able to set any user inputted first name unless you call this method with the user input value, like this: $person->setFirstName($_POST['firstname']);. Later, you can use getFirstName() method in your form to display the user inputted first name accordingly.
Here's a code example to accomplish your task,
PHP
class Person{
private $firstname = null;
public function setFirstName($aFirstName){
$this->firstname = $aFirstName;
}
public function getFirstName(){
return $this->firstname;
}
}
$person = new Person();
if(isset($_POST['submit'])){
$person->setFirstName($_POST['firstname']);
}
HTML
<form action="" method="post">
First Name: <input type="text" name="firstname" value="<?php if($person->getFirstName() != null){ echo $person->getFirstName(); } ?>"/>
<input type="submit" name="submit" value="Submit" />
</form>
The above example assumes that both HTML and PHP code should be on the same page.

Answer 2

You will be able to use the class you have defined inside the script being called by the form (at least that's the way I would do it).
person.html
<form action="savePerson.php" method="post">
First Name: <input type="text" name="firstname" id="firstname">
<button type="submit">Submit</button>
</form>
savePerson.php
<?php
class Person{
private $firstname;
public function setFirstName($aFirstName){
$this->firstname = $aFirstName;
}
public function getFirstName(){
return $this->firstname;
}
}
$person = new Person();
$person->setFirstName($_POST['firstname']);
//do something on the person object
?>

Answer 3

In this instance, you can't really declare the Firstname in the HTML form before it has been declared unless you already had this value stored somewhere else e.g. Database. You would need to use a client side language like Javascript to store and output data in real time. In terms of PHP, if you was making a call to a database or variable $aFirstName was predefined, your PHP would probably look something like this:
Person.php
class Person{
private $isSet; //Is Name Set on Object Creation
private $firstname;
public function __construct($aFirstName = false) { //Check if name is created on object creation.
if ($aFirstName === false) {
$this->isSet = false;
$this->firstname = 'No Data'; //Set so your field will always have predefined data.
} else {
$this->isSet = true;
$this->setFirstName($aFirstName);
}
}
private function setFirstName($aFirstName){
$this->firstname = $aFirstName;
}
public function getFirstName(){
return $this->firstname;
}
}
PersonForm.php
<?php //Check if Post data is set, if so then set name constructor
if (isset($_POST['firstname'])) {
$person = new Person($_POST['firstname']);
} else {
$person = new Person();
}
?>
<form method="post" action="">
First Name: <input type="text" name="firstname" value="<?php echo $person->getFirstName() ?>"/>
<input type="submit" value="submit">
</form>
This will output 'No Data' if the form input is not set or 'YOUR INSERTED DATA' if the value is set.

Answer 4

The important point to understand is PHP is working on server-side. So when you run your PHP script via a request it runs and finishes. When you hit that PersonForm.php script, it will generate the HTML document and send it to your browser, for example. That it there is no more chance to run PHP on your browser (frontend).
To store what is entered in a form you must use JavaScript/jQuery and make AJAX calls to a PHP script. So that JavaScript reads the form input and sends it to a PHP script on your backend, which will process the data like inserting it in a database etc.
I recommend you to read more about Javascript/jQuery and AJAX calls to achieve this.
A simple way to achieve it by using jQuery.
main.js
$("#submit").click(function(){
personName = $("input[name=firstname]").val();
$.ajax({
type: 'POST',
url: 'SavePerson.php',
data: {name: personName},
success: function(result, status, xhr) {
popup("Success!");
}
});
});
SavePerson.php
<?php
include_once('Person.php');
$person = new Person();
$person->setFirstName($_POST['name']);
// Do whatever you want with person...
?>
PersonForm.html
<!DOCTYPE html>
<html>
<form>
First Name: <input type="text" name="firstname" placeholder="Enter your name"/><br />
<button id="submit" value="Submit">Submit</button>
</form>
<script src='main.js'></script>
</html>