PHP static delay statically binding usage analysis _php tips

The example in this article describes the PHP static lazy binding usage. Share to everyone for your reference, specific as follows:

PHP5.3 later introduced a deferred static binding static, what is it to solve the problem? One long-standing problem with PHP's inheritance model is that it is difficult to refer to the final state of an extended class in a parent class. Take a look at an example.

Class A 
{public 
  static function Echoclass () { 
    echo __class__; 
  }
  public static function test () { 
    self::echoclass ();    
  }
}
Class B extends A 
{public    
  static function Echoclass () 
  { 
     echo __class__; 
  } 
} 
B::test (); Output A

A new feature has been added to the PHP5.3: deferred static binding, which is the expression or variable that is fixed at the defining stage, is decided at the execution stage, such as when a subclass inherits the static expression of the parent class, its value cannot be changed, and sometimes it is not desirable to see it.

The following example solves the problem raised above:

Class A 
{public 
  static function Echoclass () { 
    echo __class__; 
  } 
  public static function test () 
  { 
    static::echoclass ();    
  } 
} 
Class B extends A 
{public    
  static function Echoclass () { 
     echo __class__; 
  } 
} 
B::test (); Output b

The Static::echoclass () in line 8th defines a static deferred binding method until B invokes test to execute the method that was originally defined.

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I hope this article will help you with the PHP program design.