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Declaring Attribute Classes

It is recommended to define a separate class for each attribute. In the simplest case, an empty class with the #[Attribute] declaration is sufficient. The attribute can be imported from the global namespace using a use statement.

<?php

namespace Example;

use Attribute;

#[Attribute]
class MyAttribute
{
}

To restrict the types of declarations an attribute can be applied to, pass a bitmask as the first argument to the #[Attribute] declaration.

<?php

namespace Example;

use Attribute;

#[Attribute(Attribute::TARGET_METHOD | Attribute::TARGET_FUNCTION)]
class MyAttribute
{
}

The following targets can be specified:

• Attribute::TARGET_CLASS
• Attribute::TARGET_FUNCTION
• Attribute::TARGET_METHOD
• Attribute::TARGET_PROPERTY
• Attribute::TARGET_CLASS_CONSTANT
• Attribute::TARGET_PARAMETER
• Attribute::TARGET_ALL

By default, an attribute can only be used once per declaration. To allow an attribute to be repeatable, specify it in the bitmask of the #[Attribute] declaration using the Attribute::IS_REPEATABLE flag.

<?php

namespace Example;

use Attribute;

#[Attribute(Attribute::TARGET_METHOD | Attribute::TARGET_FUNCTION | Attribute::IS_REPEATABLE)]
class MyAttribute
{
}