Detailed explanation and examples of singleton mode and factory mode in PHP

This article mainly introduces the relevant information of PHP singleton mode and factory mode in detail, which has certain reference value. Interested friends can refer to it

1. Singleton mode and Called the responsibility pattern, it is used to create a single functional access point in the program. In layman's terms, the instantiated object is unique.
All singleton patterns have at least the following three common elements:

1. They must have a constructor and must be marked private
2. They have a saving class Static member variables of the instance
3. They have a public static method to access this instance

The singleton class cannot be directly instantiated in other classes, but can only be instantiated by itself. . It does not create a copy of the instance, but returns a reference to the instance stored internally in the singleton class.

Singleton pattern instance

name = $n; 
　　 }
  public function getname(){ //取变量$name的值
　　　　　　return $this->name; 
　　　}
 }
 
 
 $a = Single::getinstance();
 $b = Single::getinstance();
 $a->setname('hello world');
 $b->setname('good morning');
 echo $a->getname();//good morning
 echo $b->getname();//good morning
?>

2. The factory pattern is a class that has certain methods for creating objects for you. This allows you to use factory classes to create objects instead of using new directly.

So if you want to change the type of object created, you only need to change the factory.

a = 20;
$ope->b = 10;
echo $ope->opera();

Factory Pattern Example

class Factory {//创建一个基本的工厂类
  static public function fac($id){//创建一个返回对象实例的静态方法
   if(1 == $id) return new A();
   elseif(2==$id) return new B();
   elseif(3==$id) return new C();
   return new D();
  }
 }
 
 interface FetchName {//创建一个接口
  public function getname();//
 }
 
 class A implements FetchName{
  private $name = "AAAAA";
  public function getname(){ 
　　　　　　return $this->name; 
　　　　}
 }
 
 class C implements FetchName{
  private $name = "CCCCC";
  public function getname(){
　　　　　　return $this->name; 
　　　　}
 }
 class B implements FetchName{
  private $name = "BBBBB";
  public function getname(){ 
　　　　　　return $this->name;
　　　　}
 }
 
 class D implements FetchName{
  private $name = "DDDDD";
  public function getname(){ 
　　　　　　return $this->name; 
　　　　}
}
 
 
 $o = Factory::fac(6);//调用工厂类中的方法
 if($o instanceof FetchName){
 echo $o->getname();//DDDDD
 }
 
 $p=Factory::fac(3);
 echo $p->getname();//CCCCC
？>

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Singleton pattern of php pattern design

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A brief analysis of php singleton mode, a brief analysis of php mode_PHP tutorial

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