gnu-social/vendor/doctrine/annotations/docs/en/custom.rst
2021-07-16 19:44:40 +01:00

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Custom Annotation Classes
=========================
If you want to define your own annotations, you just have to group them
in a namespace and register this namespace in the ``AnnotationRegistry``.
Annotation classes have to contain a class-level docblock with the text
``@Annotation``:
.. code-block:: php
namespace MyCompany\Annotations;
/** @Annotation */
class Bar
{
// some code
}
Inject annotation values
------------------------
The annotation parser checks if the annotation constructor has arguments,
if so then it will pass the value array, otherwise it will try to inject
values into public properties directly:
.. code-block:: php
namespace MyCompany\Annotations;
/**
* @Annotation
*
* Some Annotation using a constructor
*/
class Bar
{
private $foo;
public function __construct(array $values)
{
$this->foo = $values['foo'];
}
}
/**
* @Annotation
*
* Some Annotation without a constructor
*/
class Foo
{
public $bar;
}
Annotation Target
-----------------
``@Target`` indicates the kinds of class elements to which an annotation
type is applicable. Then you could define one or more targets:
- ``CLASS`` Allowed in class docblocks
- ``PROPERTY`` Allowed in property docblocks
- ``METHOD`` Allowed in the method docblocks
- ``ALL`` Allowed in class, property and method docblocks
- ``ANNOTATION`` Allowed inside other annotations
If the annotations is not allowed in the current context, an
``AnnotationException`` is thrown.
.. code-block:: php
namespace MyCompany\Annotations;
/**
* @Annotation
* @Target({"METHOD","PROPERTY"})
*/
class Bar
{
// some code
}
/**
* @Annotation
* @Target("CLASS")
*/
class Foo
{
// some code
}
Attribute types
---------------
The annotation parser checks the given parameters using the phpdoc
annotation ``@var``, The data type could be validated using the ``@var``
annotation on the annotation properties or using the ``@Attributes`` and
``@Attribute`` annotations.
If the data type does not match you get an ``AnnotationException``
.. code-block:: php
namespace MyCompany\Annotations;
/**
* @Annotation
* @Target({"METHOD","PROPERTY"})
*/
class Bar
{
/** @var mixed */
public $mixed;
/** @var boolean */
public $boolean;
/** @var bool */
public $bool;
/** @var float */
public $float;
/** @var string */
public $string;
/** @var integer */
public $integer;
/** @var array */
public $array;
/** @var SomeAnnotationClass */
public $annotation;
/** @var array<integer> */
public $arrayOfIntegers;
/** @var array<SomeAnnotationClass> */
public $arrayOfAnnotations;
}
/**
* @Annotation
* @Target({"METHOD","PROPERTY"})
* @Attributes({
* @Attribute("stringProperty", type = "string"),
* @Attribute("annotProperty", type = "SomeAnnotationClass"),
* })
*/
class Foo
{
public function __construct(array $values)
{
$this->stringProperty = $values['stringProperty'];
$this->annotProperty = $values['annotProperty'];
}
// some code
}
Annotation Required
-------------------
``@Required`` indicates that the field must be specified when the
annotation is used. If it is not used you get an ``AnnotationException``
stating that this value can not be null.
Declaring a required field:
.. code-block:: php
/**
* @Annotation
* @Target("ALL")
*/
class Foo
{
/** @Required */
public $requiredField;
}
Usage:
.. code-block:: php
/** @Foo(requiredField="value") */
public $direction; // Valid
/** @Foo */
public $direction; // Required field missing, throws an AnnotationException
Enumerated values
-----------------
- An annotation property marked with ``@Enum`` is a field that accepts a
fixed set of scalar values.
- You should use ``@Enum`` fields any time you need to represent fixed
values.
- The annotation parser checks the given value and throws an
``AnnotationException`` if the value does not match.
Declaring an enumerated property:
.. code-block:: php
/**
* @Annotation
* @Target("ALL")
*/
class Direction
{
/**
* @Enum({"NORTH", "SOUTH", "EAST", "WEST"})
*/
public $value;
}
Annotation usage:
.. code-block:: php
/** @Direction("NORTH") */
public $direction; // Valid value
/** @Direction("NORTHEAST") */
public $direction; // Invalid value, throws an AnnotationException
Constants
---------
The use of constants and class constants is available on the annotations
parser.
The following usages are allowed:
.. code-block:: php
namespace MyCompany\Entity;
use MyCompany\Annotations\Foo;
use MyCompany\Annotations\Bar;
use MyCompany\Entity\SomeClass;
/**
* @Foo(PHP_EOL)
* @Bar(Bar::FOO)
* @Foo({SomeClass::FOO, SomeClass::BAR})
* @Bar({SomeClass::FOO_KEY = SomeClass::BAR_VALUE})
*/
class User
{
}
Be careful with constants and the cache !
.. note::
The cached reader will not re-evaluate each time an annotation is
loaded from cache. When a constant is changed the cache must be
cleaned.
Usage
-----
Using the library API is simple. Using the annotations described in the
previous section, you can now annotate other classes with your
annotations:
.. code-block:: php
namespace MyCompany\Entity;
use MyCompany\Annotations\Foo;
use MyCompany\Annotations\Bar;
/**
* @Foo(bar="foo")
* @Bar(foo="bar")
*/
class User
{
}
Now we can write a script to get the annotations above:
.. code-block:: php
$reflClass = new ReflectionClass('MyCompany\Entity\User');
$classAnnotations = $reader->getClassAnnotations($reflClass);
foreach ($classAnnotations AS $annot) {
if ($annot instanceof \MyCompany\Annotations\Foo) {
echo $annot->bar; // prints "foo";
} else if ($annot instanceof \MyCompany\Annotations\Bar) {
echo $annot->foo; // prints "bar";
}
}
You have a complete API for retrieving annotation class instances from a
class, property or method docblock:
Reader API
~~~~~~~~~~
Access all annotations of a class
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
.. code-block:: php
public function getClassAnnotations(\ReflectionClass $class);
Access one annotation of a class
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
.. code-block:: php
public function getClassAnnotation(\ReflectionClass $class, $annotationName);
Access all annotations of a method
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
.. code-block:: php
public function getMethodAnnotations(\ReflectionMethod $method);
Access one annotation of a method
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
.. code-block:: php
public function getMethodAnnotation(\ReflectionMethod $method, $annotationName);
Access all annotations of a property
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
.. code-block:: php
public function getPropertyAnnotations(\ReflectionProperty $property);
Access one annotation of a property
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
.. code-block:: php
public function getPropertyAnnotation(\ReflectionProperty $property, $annotationName);