PHP design pattern registration tree pattern analysis php skills

This article mainly introduces the registration tree pattern of PHP design pattern. It analyzes the concept, principle, implementation method and related precautions of the registration tree pattern in detail with examples. Friends in need can refer to it

This article describes the PHP registration tree mode with examples. Share it with everyone for your reference, the details are as follows:

What is the registration tree mode?

The registration tree mode is of course also called registration mode and registrar mode. The reason why I am pretentious about its name here is because I feel that the name registration tree is easier for people to understand. Like the previous two articles, our article still starts with the name. The registration tree pattern is a pattern design method that registers object instances to a global object tree and picks from the object tree when needed. This reminds me of buying candied haws on a stick when I was a kid. The candied haws seller would stick the candied haws on a big pole and people would take them off when they bought them. The difference is that the registration tree model will still have it after it is picked, and it can be picked many times, but the candied haws will be gone after being picked once. . .

Why should we use registration tree mode?

The singleton mode solves the problem of how to create a unique object instance in the entire project, and the factory mode solves the problem of how to create an instance object without using new. So what problem does the registration tree mode want to solve? Before considering this issue, we still need to consider the limitations currently faced by the first two models. First of all, the process of creating a unique object in the singleton mode itself also has a judgment, that is, whether the object exists. If it exists, the object is returned; if it does not exist, the object is created and returned. Every time an instance object is created, there must be such a layer of judgment. The factory model considers more the issue of extended maintenance. In general, the singleton pattern and factory pattern can produce more reasonable objects. How to conveniently call these objects? Moreover, the objects created in this way in the project are like scattered soldiers, making it inconvenient for overall management and arrangement. Therefore, the registration tree model came into being. Regardless of whether you generate objects through singleton mode, factory mode, or a combination of the two, they are all "inserted" into the registration tree. When I use an object, I just fetch it directly from the registration tree. This is as convenient and practical as using global variables. And the registration tree pattern also provides a very good idea for other patterns.

How to implement the registration tree?

Through the above description, we seem to have easily found a solution. First we need a class as a registration tree, of course. All objects are "inserted" into the registration tree. This registration tree should be served by a static variable. And this registration tree should be a two-dimensional array. This class should have a method for inserting object instances (set()), and correspondingly there should be a method for unsetting object instances (_unset()). Of course, the most important thing is to have a method to read the object (get()). With these, we can happily complete the registration tree mode~~~

Let’s make a small combination of the three modes. Simply creating an instance object is far less complicated, but when applied to large projects, the convenience is self-evident.

<?php
//创建单例
class Single{
  public $hash;
  static protected $ins=null;
  final protected function __construct(){
    $this->hash=rand(1,9999);
  }
  static public function getInstance(){
    if (self::$ins instanceof self) {
      return self::$ins;
    }
    self::$ins=new self();
    return self::$ins;
  }
}
//工厂模式
class RandFactory{
  public static function factory(){
    return Single::getInstance();
  }
}
//注册树
class Register{
  protected static $objects;
  public static function set($alias,$object){
    self::$objects[$alias]=$object;
  }
  public static function get($alias){
    return self::$objects[$alias];
  }
  public static function _unset($alias){
    unset(self::$objects[$alias]);
  }
}
Register::set(&#39;rand&#39;,RandFactory::factory());
$object=Register::get(&#39;rand&#39;);
print_r($object);

At this point, the introduction of the three modes of design is completed. Various pattern designs themselves will complement each other. When introducing other patterns in the future, one or more other design patterns will be used more or less.

It doesn’t matter if you don’t understand a certain model. I believe that with the in-depth programming, there will be a surprise of sudden enlightenment. I hope you will make progress with me.

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