Руководство по PHP
Пред. | Глава 19. Классы и объекты (PHP 5) | След.

# Type Hinting

PHP 5 introduces Type Hinting. Functions are now able to force parameters to be objects by specifying the name of the class in the function prototype.

Пример 19-38. Type Hinting example
`<?php // An example class class MyClass { /** * A test function * * First parameter must be an object of type OtherClass */ public function test(OtherClass $otherclass) { echo $otherclass->var; } } // Another example class class OtherClass { public $var = 'Hello World'; } ?>`
Failing to satisfy the type hint results in a fatal error.
`<?php // An instance of each class $myclass = new MyClass; $otherclass = new OtherClass; // Fatal Error: Argument 1 must be an object of class OtherClass $myclass->test('hello'); // Fatal Error: Argument 1 must be an instance of OtherClass $foo = new stdClass; $myclass->test($foo); // Fatal Error: Argument 1 must not be null $myclass->test(null); // Works: Prints Hello World $myclass->test($otherclass); ?>`
Type hinting also works with functions:
`<?php // An example class class MyClass { public $var = 'Hello World'; } /** * A test function * * First parameter must be an object of type MyClass */ function MyFunction (MyClass $foo) { echo $foo->var; } // Works $myclass = new MyClass; MyFunction($myclass); ?>`

Type Hints can only be of the object type. Traditional type hinting with int and string are not supported.

Пред. | Начало | След.
Reflection | Уровень выше | Exceptions