Getting Started
===============

Deprecation notice
------------------

PHP 8 introduced `attributes
<https://www.php.net/manual/en/language.attributes.overview.php>`_,
which are a native replacement for annotations. As such, this library is
considered feature complete, and should receive exclusively bugfixes and
security fixes.

We do not recommend using this library in new projects and encourage authors
of downstream libraries to offer support for attributes as an alternative to
Doctrine Annotations.

Have a look at `our blog <https://www.doctrine-project.org/2022/11/04/annotations-to-attributes.html>`_
to learn more.

Introduction
------------

Doctrine Annotations allows to implement custom annotation
functionality for PHP classes and functions.

.. code-block:: php

    class Foo
    {
        /**
         * @MyAnnotation(myProperty="value")
         */
        private $bar;
    }

Annotations aren't implemented in PHP itself which is why this component
offers a way to use the PHP doc-blocks as a place for the well known
annotation syntax using the ``@`` char.

Annotations in Doctrine are used for the ORM configuration to build the
class mapping, but it can be used in other projects for other purposes
too.

Installation
------------

You can install the Annotation component with composer:

.. code-block::

    $ composer require doctrine/annotations

Create an annotation class
--------------------------

An annotation class is a representation of the later used annotation
configuration in classes. The annotation class of the previous example
looks like this:

.. code-block:: php

    /**
     * @Annotation
     */
    final class MyAnnotation
    {
        public $myProperty;
    }

The annotation class is declared as an annotation by ``@Annotation``.

:doc:`Read more about custom annotations. <custom>`

Reading annotations
-------------------

The access to the annotations happens by reflection of the class or function
containing them. There are multiple reader-classes implementing the
``Doctrine\Common\Annotations\Reader`` interface, that can access the
annotations of a class. A common one is
``Doctrine\Common\Annotations\AnnotationReader``:

.. code-block:: php

    use Doctrine\Common\Annotations\AnnotationReader;

    $reflectionClass = new ReflectionClass(Foo::class);
    $property = $reflectionClass->getProperty('bar');

    $reader = new AnnotationReader();
    $myAnnotation = $reader->getPropertyAnnotation(
        $property,
        MyAnnotation::class
    );

    echo $myAnnotation->myProperty; // result: "value"

A reader has multiple methods to access the annotations of a class or
function.

:doc:`Read more about handling annotations. <annotations>`

IDE Support
^^^^^^^^^^^

Some IDEs already provide support for annotations:

- Eclipse via the `Symfony2 Plugin <https://github.com/pulse00/Symfony-2-Eclipse-Plugin>`_
- PhpStorm via the `PHP Annotations Plugin <https://plugins.jetbrains.com/plugin/7320-php-annotations>`_ or the `Symfony Plugin <https://plugins.jetbrains.com/plugin/7219-symfony-support>`_
