PHP design Pattern notes and summaries (5) Use of the PHP magic method

Use of the PHP magic method

①__get/__set: taking over the properties of an object

When accessing a non-existent object property:

index.php

<? PHP Define // defining a root directory constant include BASEDIR. ' /common/loader.php '; Spl_autoload_register (' \\common\\loader::autoload '); $obj new \common\Object();   // when accessing a non-existent object property in PHP Echo $obj->title;

Throws an error: notice:undefined property:common\object:: $title in D:\practise\php\design\psr0\index.php on line 9

After you add the __set and __get methods in common/object.php

object.php

<? phpnamespace Common; class Object {    function __set ($key,$value) {    }        function __get ($key) {    }}

Execute index.php again, no more error.

Modify common/object.php again

<?phpnamespace Common;class Object{    protected $array=Array(); function__set ($key,$value){        Var_dump(__method__); $this-Array[$key] =$value; }        function__get ($key){        Var_dump(__method__); return $this-Array[$key]; }}

index.php

<? PHP Define // defining a root directory constant include BASEDIR. ' /common/loader.php '; Spl_autoload_register (' \\common\\loader::autoload '); $obj new \common\Object();   $obj->title = ' Hello '; Echo $obj->title;

Execute index.php, page output:

string ' Common\object::__set ' (length=20)string ' Common\object::__get ' (length=20) Hello

②__call/__callstatic: A call to control the PHP object method (__callstatic is used to control the static method of the Class)

When executing a non-existent PHP method

index.php:

<? PHP Define // defining a root directory constant include BASEDIR. ' /common/loader.php '; Spl_autoload_register (' \\common\\loader::autoload '); $obj new \common\Object();   // When executing a non-existent PHP method $obj->test (' Hello ', 123);

Execution index.php will report a fatal error: Fatal error:call to undefined method common\object::test () in D:\practise\php\design\psr0\ index.php on line 9

If you define a __call method in Common/object, the callback is automatically when the method does not exist:

<? phpnamespace Common; class Object {        function __call ($func$param//$func method name $param parameter        Var_dump ($func$param);         return // returns a string as the return value     }}

index.php

<? PHP Define // defining a root directory constant include BASEDIR. ' /common/loader.php '; Spl_autoload_register (' \\common\\loader::autoload '); $obj new \common\Object();   // When executing a non-existent PHP method Echo $obj->test (' Hello ', 123);

Page output:

string ' Test ' (length=4)array  string ' Hello ' (length=5)  1 = int 123   function

When a static method that does not exist is called

common/object.php

<? phpnamespace Common; class Object {    staticfunction __callstatic ($name$arguments) {         Var_dump ($name$arguments);         return // returns a string as the return        value     }}

Note: The __callstatic method is also declared as a static method

index.php

<? PHP Define // defining a root directory constant include BASEDIR. ' /common/loader.php '; Spl_autoload_register (' \\common\\loader::autoload '); // executes a static method that does not exist Echo common\Object:: Test ("Hello", 1234);

Execute index.php, page output:

string ' Test ' (length=4)array  string ' Hello ' (length=5)  1 = int 1234   function

③__tostring: Converts a PHP object into a string

index.php

<? PHP Define // defining a root directory constant include BASEDIR. ' /common/loader.php '; Spl_autoload_register (' \\common\\loader::autoload '); $obj new \common\Object(); Echo $obj;

This will cause an error: Catchable fatal error:object of class Common\object could not being converted to string in D:\PRACTISE\PHP\DESIGN\PSR 0\index.php on line 8

Adding __tostring methods in object.php

<? phpnamespace Common; class Object {    function  __tostring () {        return__class__;    }}

At this point, execute index.php, output:

common\Object

④__invoke: When a PHP object is executed as a function, this magic method is recalled

index.php

<? PHP Define // defining a root directory constant include BASEDIR. ' /common/loader.php '; Spl_autoload_register (' \\common\\loader::autoload '); $obj new \common\Object(); Echo $obj ("Test");

object.php

<? phpnamespace Common; class Object {    function __invoke ($param) {        var_dump($param );         return ' Invoke ';    }}

Page output:

string ' Test ' (length=4) Invoke

PHP design Pattern notes and summaries (5) Use of the PHP magic method