PHP ReflectionClass::getInterfaceNames() Method: Usage and Examples

ReflectionClass inspects the definition of a class, rather than running its constructor or calling its methods.

What Is ReflectionClass::getInterfaceNames in PHP?

Returns an array of interface names implemented by the class, including inherited interfaces.

ReflectionClass::getInterfaceNames()

This operation does not accept method arguments.

Example 1: Understanding the Basic Behavior

<?php

class Report { public const VERSION = 2; public string $title = 'Draft'; protected int $pages = 10; public static string $category = 'docs'; public function publish(): void {} }
$reflectionClass = new ReflectionClass(Report::class);
$result = $reflectionClass->getInterfaceNames();
var_dump($result);

Output:

array(0) {
}

Explanation: Returns an array of interface names implemented by the class, including inherited interfaces.

Example 2: Testing Another Case

<?php

interface Exportable { public function export(): string; }
trait HasId { public function getId(): int { return 12; } }
class Invoice implements Exportable { use HasId; public string $name = 'Invoice'; public const STATE = 'open'; public function export(): string { return 'invoice'; } }
$reflectionClass = new ReflectionClass(Invoice::class);
$result = $reflectionClass->getInterfaceNames();
var_dump($result);

Output:

array(1) {
  [0]=>
  string(10) "Exportable"
}

Explanation: The result includes inherited interfaces; these are names rather than interface descriptor objects.

Practical Example: Applying the Operation

<?php

abstract class BaseJob { protected string $name = 'job'; abstract public function run(): void; }
class CompletedJob extends BaseJob { public function run(): void {} }
$reflectionClass = new ReflectionClass(CompletedJob::class);
$result = $reflectionClass->getInterfaceNames();
var_dump($result);

Output:

array(0) {
}

Explanation: The returned metadata may be false, null, an array, or a Reflection object depending on the requested property.

Important Behavior and Edge Cases

• The result includes inherited interfaces; these are names rather than interface descriptor objects.
• The returned metadata may be false, null, an array, or a Reflection object depending on the requested property.

Comparison With Related Approaches

Common Beginner Mistakes

Key Takeaways

• Returns an array of interface names implemented by the class, including inherited interfaces.
• The result includes inherited interfaces; these are names rather than interface descriptor objects.
• The returned metadata may be false, null, an array, or a Reflection object depending on the requested property.

The examples demonstrate where ReflectionClass::getInterfaceNames fits within reflection and metadata. Verify the relevant preconditions whenever you adapt the code to real data.