Advanced Search

Interface-defined constants and implementing classes.

/ Published in: PHP
Save to your folder(s)
A class that implements an interface cannot override a constant defined in the interface. But any child class that extends from the implementing class can.

Expand | Embed | Plain Text

Copy this code and paste it in your HTML 
  1. <?php
  2.  
  3. interface FooInterface
  4. {
  5.     /**
  6.      * Define a constant
  7.      */
  8.     const FOO = 'foo';
  9. }
  10.  
  11. class Bar implements FooInterface
  12. {
  13.     /**
  14.      * As noted in the PHP docs:
  15.      *
  16.      * An implementing class can 
  17.      * not override an interface 
  18.      * defined constant...
  19.      */
  20.     const FOO = 'bar'; // FATAL ERROR! 
  21. }
  22.  
  23. class Baz extends Bar
  24. {
  25.     /**
  26.      * However, a child of an 
  27.      * implementing class can 
  28.      * override an interface 
  29.      * defined constant :)
  30.      */
  31.     const FOO = 'baz'; // WORKS!
  32. }

Report this snippet


Comments

RSS Icon Subscribe to comments

You need to login to post a comment.