I'm having hard times, learning desing patterns. And, I've been reading quite a lot. But, I'm only interested to know, about two things: Adapter & Factory patterns.
From what I undestood, (which is close to nothing)
Factory Pattern helps create objects on the fly
Adapter Pattern helps adapt your class from changes made externally.
That is the only thing I undetood. Which is why, I am looking for simples possible, practical examples on either both if possible. on how to use them. So, I am providing just, two simple classes, only to help any demostrate the purpose of the two patterns I mentioned. And, How they can improve my classes, or do anything helpful.
Let's say, this class helps check somethings in a string.
class Sanitize{
public $errors = [];
function checkEmail($email){
if(!isset($email) || empty($email)){
return $this->error = ' <em> Email is required </em>';
}else if(filter_var($email, FILTER_VALIDATE_EMAIL) === false){
return $this->error = ' <em> Please enter a valid email address </em>';
}else if(strlen($email) > 40){
return $this->error = ' <em> Email should be less than 40 characters long </em>';
}else{
return true;
}
}
function checkPassword($pass, $re_pass, $min, $max){
if(empty($pass) && empty($re_pass)){
return $this->error = ' <em> You must enter a password to register </em>';
}else if($pass !== $re_pass){
return $this->error = ' <em> Your passwords are not the same </em>';
}else if(strlen($pass) < $min || strlen($pass) > $max){
return $this->error = ' <em> Passwords should be between, $min to $max characters in length </em>';
}else{
return true;
}
}
function Check_Age($year, $month, $day){
if($year > date('Y')-13){
return $this->error = '<em> You must be over 13 years old, to register </em>';
}else{
return true;
}
}
function checkErrors(){
return $this->errors;
}
}
And, let's assume this class helps with database queries.
class QueryClass{
public $conn;
private $error;
function __construct($conn){
$this->conn = $conn;
}
function checkExsitingData($column, $table, $value, $input){
try{ $stmt = $this->conn->prepare("SELECT $column FROM $table WHERE $value = ?");
$stmt->execute(array($input));
}catch(PDOExeption $e){
return $this->error = ' Unknown error occured. Please try again later.';
}
if($stmt->rowCount() !== 0){
return $this->error = ' This email is already registred, please try password recovery or create new account ';
}else{
return true;
}
}
function registerPerson($P){
try{ $stmt = $this->conn->prepare("INSERT INTO clients (person_name, timeof_reg) VALUES (?, NOW())");
$stmt->execute(array($P['username']);
}catch(PDOExeption $e){
return $this->error = '<em> Date could not be submitted into database </em>';
}
}
// for "contact us" page form
function guestbookSubmit($table, $P){
try{
$stmt = $this->conn->prepare("INSERT INTO $table (username, email, telephone, message) VALUES (?,?,?,?) ");
$stmt->execute(array($P['username'], $P['email'], $P['telephone'], $P['message']));
}catch(PDOException $e){
return $this->error = '<em> Some errros occured while sending your email. Please try again later </em>';
}
if($stmt->rowCount() === 0){
return ' <em> Your Details, could not be submitted </em>'.spy($stmt->conn);
}else{
return true;
}
}
function insertToDatabase($tableName, $postGlobal = []){
$stmt = $this->conn->prepare("INSERT INTO clients (company, tel, city, email, category)
VALUES (?,?,?,?,?)
");
$stmt->execute( array(
$postGlobal['company'],
$postGlobal['tel'],
$postGlobal['city'],
$postGlobal['email'],
$postGlobal['category']
)
);
return ($stmt->rowCount() == 0) ? $this->error = 'Insert failed, please try again later' : (int)$this->conn->lastInsertId();
}
Don't pay attention to the mistakes in the classes, I copy pasted, an ancient code of mine, just to give this simple example.
Now, having said that, say if I wanted to validate an e-mail and submit it to database, I probably would do...
$Sanitize = new Sanitize();
$checkEmail = $Sanitize->checkEmail($_POST['email']);
if(!$Sanitize->checkErrors){
$QueryClass = new QueryClass(new PDO('mysql:host; .....'));
$checkDuplicate = $QueryClass->checkExsitingData('email', 'tableName', 'email', $_POST['email']);
if($checkDuplicate){
echo 'Email exists';
}else{
$InsertToDb = $QueryClass->insertToDatabase('emails', $_POST);
if($InsertToDb){
echo 'Email is inserted into database';
}else{
echo 'query failed';
}
}
}
Now, what I want to know, is that ... you have seen my classes, and I need opinions, as to how I can apply even a smallest portion of Adapter or Factory pattern to better anything in that code. Because, I am sure, this is the only way I can undestand the use cases for them.
BTW: I am trying to create a large-scale news website, which is a personal and very important project for me, with many functionalities, and I don't want to start without at-least getting a basic idea of Adapter or Factory pattern. As it is likly, that even a simple usage might help a lot in making my code, DRY, extendable and anyother OOP principles, that can be helpful for refractoring/optimizing/extending the script in the future, which I am sure I will need.
