Binding time

The following Java code demonstrates both binding times. The method foo is early-bound to the code block that follows the function declaration on line 3. The call to add is late-bound since List is an interface, so list must refer to a subtype of it. list may reference a LinkedList, an ArrayList, or some other subtype of List. The method referenced by add is not known until runtime.

import java.util.List; public void foo(List<String> list) { list.add("bar"); }

Late static

Late static binding is a variant of binding somewhere between static and dynamic binding. Consider the following PHP example:

class A { public static $word = "hello"; public static function hello() { print self::$word; } } class B extends A { public static $word = "bye"; } B::hello();

In this example, the PHP interpreter binds the keyword self inside A::hello() to class A, and so the call to B::hello() produces the string "hello". If the semantics of self::$word had been based on late static binding, then the result would have been "bye".

Beginning with PHP version 5.3, late static binding is supported. Specifically, if self::$word in the above were changed to static::$word as shown in the following block, where the keyword static would only be bound at runtime, then the result of the call to B::hello() would be "bye":

class A { public static $word = "hello"; public static function hello() { print static::$word; } } class B extends A { public static $word = "bye"; } B::hello();