forward_static_call

(PHP 5 >= 5.3.0, PHP 7, PHP 8)

forward_static_call — Call a static method

说明

forward_static_call ( callable $function , mixed $parameter = ? , mixed $... = ? ) : mixed

Calls a user defined function or method given by the function parameter, with the following arguments. This function must be called within a method context, it can't be used outside a class. It uses the late static binding.

参数

function: The function or method to be called. This parameter may be an array, with the name of the class, and the method, or a string, with a function name.
parameter: Zero or more parameters to be passed to the function.

返回值

Returns the function result, or false on error.

范例

Example #1 forward_static_call() example


<?php

class A
{
    const NAME = 'A';
    public static function test() {
        $args = func_get_args();
        echo static::NAME, " ".join(',', $args)." \n";
    }
}

class B extends A
{
    const NAME = 'B';

    public static function test() {
        echo self::NAME, "\n";
        forward_static_call(array('A', 'test'), 'more', 'args');
        forward_static_call( 'test', 'other', 'args');
    }
}

B::test('foo');

function test() {
        $args = func_get_args();
        echo "C ".join(',', $args)." \n";
    }

?>

以上例程会输出：

B
B more,args 
C other,args

参见

forward_static_call_array() - Call a static method and pass the arguments as array
call_user_func_array() - 调用回调函数，并把一个数组参数作为回调函数的参数
call_user_func() - 把第一个参数作为回调函数调用
is_callable() - 检测参数是否为合法的可调用结构

User Contributed Notes

jhibbard at gmail dot com 19-Jun-2012 07:55


Example usage via calls outside of the class and within an object:



<?php

/**

 * @author Jonathon Hibbard

 */

class foo {

  # used to verify we're actually setting something..

  private static $value = '';



  /**

   * Simple setter for the static method setValue...

   */

  public static function set($method_identifier, $value_to_pass = '') {

    # make sure we have the right method format...

    # another semi-useful example is like this (useful for REST-like requests...): str_replace(" ", "", ucwords(str_replace("_", " ",  $method_identifier)));

    $static_method = 'set' . ucfirst(strtolower(trim($method_identifier)));



    if(method_exists(__CLASS__, $static_method)) {

      //Note:  this will not work and will throw PHP Parse error:  syntax error, unexpected '::'

      //__CLASS__::$static_method($value_to_pass);



      foo::$static_method($value_to_pass);



      echo "\tCalling forward_static_call with pure string and value param:\n";

      forward_static_call(__CLASS__ . "::" . $static_method, $value_to_pass);



      echo "\tCalling forward_static_call with class, method array and value param:\n";

      forward_static_call(array(__CLASS__, $static_method), $value_to_pass);

    }

  }



  /**

   * Set self::$value to something?

   */

  public static function setValue($value_recieved = '') {

    echo "\t\tsetValue called with param of " . var_export($value_recieved, true) . "!\n";



    echo "\t\tSetting Private 'value'...\n";



    self::$value = $value_recieved;



    echo "\t\tChecking the Private 'value':\n";

    if(!empty(self::$value)) {

      echo "\t\t\tPrivate 'value' was set to '" . self::$value . "' as expected!\n";

    } else {

      echo "\t\t\tPrivate 'value' was not set!\n";

    }



    # Reset...

    self::$value = '';

  }



  /**

   * Create an object and test calling the static method from within this realm...

   */

  public function __construct() {

    echo "\tCalling from within constructor..\n";

    foo::set('value','Something else from within the instance!');

  }

}



echo "\n============ Calling by static method first ============\n";

foo::set('value','Something from outside of the foo class!');



echo "\n============ Calling by static method without a value next ============\n";

foo::set('value');



echo "\n============ Calling by createing an instance next ============\n";

new foo();

?>

arthur dot techarts at gmail dot com 12-Jul-2011 07:39


Example to understand this function and difference with call_user_func:





<?php


class Beer {


    const NAME = 'Beer!';


    public static function printed(){


        echo 'static Beer:NAME = '. static::NAME . PHP_EOL;


    }


}





class Ale extends Beer {


    const NAME = 'Ale!';


    public static function printed(){


        forward_static_call(array('parent','printed'));


        call_user_func(array('parent','printed'));





        forward_static_call(array('Beer','printed'));


        call_user_func(array('Beer','printed'));


    }


}





Ale::printed();


echo '</pre>';


?>