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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:

1namespace MyCompany\Annotations; /** @Annotation */ class Bar { // some code }
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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:

1namespace 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; }
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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.

1namespace MyCompany\Annotations; /** * @Annotation * @Target({"METHOD","PROPERTY"}) */ class Bar { // some code } /** * @Annotation * @Target("CLASS") */ class Foo { // some code }
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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

1namespace 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 }
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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:

1/** * @Annotation * @Target("ALL") */ class Foo { /** @Required */ public $requiredField; }
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Usage:

1/** @Foo(requiredField="value") */ public $direction; // Valid /** @Foo */ public $direction; // Required field missing, throws an AnnotationException
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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:

1/** * @Annotation * @Target("ALL") */ class Direction { /** * @Enum({"NORTH", "SOUTH", "EAST", "WEST"}) */ public $value; }
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Annotation usage:

1/** @Direction("NORTH") */ public $direction; // Valid value /** @Direction("NORTHEAST") */ public $direction; // Invalid value, throws an AnnotationException
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Constants

The use of constants and class constants is available on the annotations parser.

The following usages are allowed:

1namespace 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 { }
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Be careful with constants and the cache !

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:

1namespace MyCompany\Entity; use MyCompany\Annotations\Foo; use MyCompany\Annotations\Bar; /** * @Foo(bar="foo") * @Bar(foo="bar") */ class User { }
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Now we can write a script to get the annotations above:

1$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"; } }
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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

1public function getClassAnnotations(\ReflectionClass $class);

Access one annotation of a class

1public function getClassAnnotation(\ReflectionClass $class, $annotationName);

Access all annotations of a method

1public function getMethodAnnotations(\ReflectionMethod $method);

Access one annotation of a method

1public function getMethodAnnotation(\ReflectionMethod $method, $annotationName);

Access all annotations of a property

1public function getPropertyAnnotations(\ReflectionProperty $property);

Access one annotation of a property

1public function getPropertyAnnotation(\ReflectionProperty $property, $annotationName);