// Объявим интерфейс 'iTemplate'
interface iTemplate
{
    public function setVariable($name, $var);
    public function getHtml($template);
}
// Реализуем интерфейс
// Это сработает нормально
class Template implements iTemplate
{
    private $vars = array();
  
    public function setVariable($name, $var)
    {
        $this->vars[$name] = $var;
    }
  
    public function getHtml($template)
    {
        foreach($this->vars as $name => $value) {
            $template = str_replace('{' . $name . '}', $value, $template);
        }
 
        return $template;
    }
}
// Это не будет работать
// Fatal error: Class BadTemplate contains 1 abstract methods
// and must therefore be declared abstract (iTemplate::getHtml)
// (Фатальная ошибка: Класс BadTemplate содержит 1 абстрактный метод
// и поэтому должнен быть объявлен абстрактным (iTemplate::getHtml))
class BadTemplate implements iTemplate
{
    private $vars = array();
  
    public function setVariable($name, $var)
    {
        $this->vars[$name] = $var;
    }
}

Пример #2 Расширяемые интерфейсы

interface a
{
    public function foo();
}
interface b extends a
{
    public function baz(Baz $baz);
}
// Это сработает
class c implements b
{
    public function foo()
    {
    }
    public function baz(Baz $baz)
    {
    }
}
// Это не сработает и выдаст фатальную ошибку
class d implements b
{
    public function foo()
    {
    }
    public function baz(Foo $foo)
    {
    }
}

Пример #3 Множественное наследование интерфейсов

interface a
{
    public function foo();
}
interface b
{
    public function bar();
}
interface c extends a, b
{
    public function baz();
}
class d implements c
{
    public function foo()
    {
    }
    public function bar()
    {
    }
    public function baz()
    {
    }
}

Пример #4 Интерфейсы с константами

interface a
{
    const b = 'Константа интерфейса';
}
// Выведет: Константа интерфейса
echo a::b;
// Вот это, однако, не будет работать, так как  
// константы перекрывать нельзя.
class b implements a
{
    const b = 'Class constant';
}

Интерфейс, совместно с контролем типов, предоставляет отличный способ проверки того, что определенный объект содержит определенный набор методов. Смотрите также оператор instanceof и контроль типов.

User Contributed Notes 38 notes

45
dlovell2001 at yahoo dot com ¶1 year ago

interface isStuffed {
    public function getStuff($something=17);
}
class oof implements isStuffed {
    public function getStuff($a=42) {
        return $a;
    }
}
$oof = new oof;
echo $oof->getStuff();

3
marasek AT telton POINT de ¶7 years ago

interface Comparable
{function compare(self $compare);}

7
mat.wilmots (at) wanadoo (dot) fr ¶8 years ago

interface SQL_Result extends SeekableIterator, Countable
{
    // new stuff
}
abstract class SQL_Result_Common
{
    // just because that's what one would do in reality, generic implementation
}
class SQL_Result_mysql extends SQL_Result_Common implements SQL_Result
{
   // actual implementation
}

2
tobias_demuth at web dot de ¶8 years ago

interface Foo {
      function bar();
}
abstract class FooBar implements Foo {
       abstract function bar(); // just for making clear, that this
                                 // method has to be implemented
}

4
drieick at hotmail dot com ¶3 years ago

interface Auxiliary_Platform {
    public function Weapon();
    public function Health();
    public function Shields();
}
class T805 implements Auxiliary_Platform {
    public function Weapon() {
        var_dump(__CLASS__);
    }
    public function Health() {
        var_dump(__CLASS__ . "::" . __FUNCTION__);
    }
    public function Shields() {
        var_dump(__CLASS__ . "->" . __FUNCTION__);
    }
}
class T806 extends T805 implements Auxiliary_Platform {
    public function Weapon() {
        var_dump(__CLASS__);
    }
    public function Shields() {
        var_dump(__CLASS__ . "->" . __FUNCTION__);
    }
}
$T805 = new T805();
$T805->Weapon();
$T805->Health();
$T805->Shields();
echo "<hr />";
$T806 = new T806();
$T806->Weapon();
$T806->Health();
$T806->Shields();
/* Output:
string(4) "T805"
string(12) "T805::Health"
string(13) "T805->Shields"
<hr />string(4) "T806"
string(12) "T805::Health"
string(13) "T806->Shields"
*/

1
Vladimir Kornea ¶5 months ago

#file : fruit/squeezable.php
namespace fruit
use Bar\Foo;
interface squeezable {
  public function squeeze (Foo $foo);
}

1
thanhn2001 at gmail dot com ¶2 years ago

interface a
{
    const b = 'Interface constant';
}
// Prints: Interface constant
echo a::b;
class b implements a
{
}
// This works!!!
class c extends b
{
    const b = 'Class constant';
}
echo c::b;

0
tkostantinov ¶9 days ago

interface I
{
  function foo(stdClass $arg);
}
class Test extends stdClass
{
}
class Implementation implements I
{
  function foo(Test $arg)
    {
    }
}

0
Vladimir Kornea ¶4 months ago

$bar = new foo(); // Valid
class foo
{
    
}

0
Anonymous ¶3 years ago

interface IDoSomething {
    public static function doSomething();
}
class One implements IDoSomething {
    public static function doSomething() {
        echo "One is doing something\n";
    }
}
class Two extends One {
    public static function doSomething() {
        echo "Two is doing something\n";
    }
}
function example(IDoSomething $doer) {
    $doer::doSomething(); // "unexpected ::" in PHP 5.2
}
example(new One()); // One is doing something
example(new Two()); // Two is doing something

0
rskret at ranphilit dot com ¶4 years ago

# modify iface b...adding $num to get better understanding
interface b extends a
{
    public function baz(Baz $baz,$num);
}
# mod claas c 
class c implements b
{
    public function foo()
    {
        echo'foo from class c';
    }
    public function baz(Baz $baz,$num)
    {
        var_dump ($baz);# object(Baz)#2 (1) { ["bb"]=>  string(3) "hot" }
        echo '<br />';
        echo $baz->bb." $num";echo '<br />';# hot 6
    }
}
# add a class Baz...
class Baz
{
    public $bb='hot';
    function ebaz(){    
        echo'this is BAZ';
    }
}
# set instance of Baz and get some output...
$bazI=new Baz;
baz::ebaz();echo '<br />';# this is BAZ
c::baz($bazI,6);

0
cretz ¶5 years ago

interface ElectricalDevice{
  public function power_on();
  public function power_off();
}
interface FrequencyTuner{
  public function get_frequencey();
  public function set_frequency($f);
}
class ElectricFan implements ElectricalDevice{
  // define ElectricalDevice...
}
class MicrowaveOven implements ElectricalDevice{
  // define ElectricalDevice...
}
class StereoReceiver implements ElectricalDevice, FrequencyTuner{
  // define ElectricalDevice...
  // define FrequencyTuner...
}
class CellPhone implements ElectricalDevice, FrequencyTuner{
  // define ElectricalDevice...
  // define FrequencyTuner...
}

0
secure_admin ¶5 years ago

class Weather{
  public $time, $temperature, $humidity;
  public function __construct($tm, $t, $h){
    $this->time = $tm;
    $this->temperature = $t;
    $this->humidity = $h;
  }
  public function __toString(){
    return "Time: $this->time, 
      Temperature: $this->temperature°, 
      Humidity: $this->humidity%";
  }
}
$forecasts = array(
  new Weather("1:00 pm", 65, 42),
  new Weather("2:00 pm", 66, 40),
  new Weather("3:00 pm", 68, 39)
  // add more weather reports as desired...
);
echo "Forecast for Chicago, IL:<br />";
foreach($forecasts as $forecast) echo ' - ' . $forecast '<br />';

0
mehea ¶5 years ago

interface water
{
    public function makeItWet();
}
 
/**
   * abstract class implements water but defines makeItWet
   * in the most general way to allow child class to 
   * provide specificity
**/
abstract class weather implements water                    
{
   private $cloudy;
   public function makeItWet(){}
   abstract public function start();
   abstract public function getCloudy();
   abstract public function setCloudy();
}
class rain extends weather                            {
    private $cloudy;    
    public function start() {
        return "Here's some weather. ";
    }
    
    public function makeItWet() {
        return 'it is raining cats and dogs today.';
    }
    public function getCloudy() {
        return $this->cloudy;
    }
    public function setCloudy($bln=false) {
        $this->cloudy = $bln;
    }
}
$a = new rain();
echo $a->start();
$a->setCloudy(true);
if ($a->getCloudy()) {
    echo 'It is a cloudy day and ';
}
echo $a->makeItWet();

0
logik at centrum dot cz ¶5 years ago

interface water
{
    public function makeItWet();
}
class weather
{
    public function makeItWet()
    {
        return 'it may or may not be wet';
    }
    
    public function start()
    {
        return 'Here is some weather';
    }
}
class rain extends weather implements water
{
    public function makeItWet()
    {
        return 'It is wet';
    }
}
class thunder extends weather implements water
{
}
$a = new rain();
echo $a->start() . "\n";
echo $a->makeItWet() . "\n";
$a = new thunder();
echo $a->start() . "\n";
echo $a->makeItWet() . "\n";

0
kaisershahid at gmail dot com ¶5 years ago

interface myInterface{
  public function setStuff($id, $name);
}
class MyFirstClass implements myInterface{
  public function setStuff($id, $name);
}
class MySecondClass implements myInterface{
 public function setStuff($id, $name, $type); 
}
class myThirdClass implements myInterface{
 public function setStuff($id, $name, $type=0);
}

0
nrg1981 {AT} hotmail {DOT} com ¶6 years ago

interface water
{
    public function makeItWet();
}
class weather
{
    public function start()
    {
        return 'Here is some weather';
    }
}
class rain extends weather implements water 
{
    public function makeItWet()
    {
        return 'It is wet';
    }
}
$a = new rain();
echo $a->start();
echo $a->makeItWet();

0
Hayley Watson ¶6 years ago

interface isStuffable
{
    public function getStuffed($ratio=0.5);
}
class Turkey implements isStuffable
{
    public function getStuffed($stuffing=1)
    {
        // ....
    }
}

0
zedd at fadingtwilight dot net ¶6 years ago

    abstract class IFoo
    {
        abstract public function Foo();
    }
    
    abstract class IBar extends IFoo
    {
        // Fails; abstract method IFoo::Foo() must be defined in child and must match parent's definition
        abstract public function Foo($bar);
    }

0
Maikel ¶6 years ago

class MyChildClass extends MyParentClass implements MyInterface
{
   // definition
}

0
Chris AT w3style DOT co.uk ¶7 years ago

interface Foo {
    public function doFoo();
}
interface Bar extends Foo {
    public function doBar();
}
class Zip implements Bar {
    public function doFoo() {
        echo "Foo";
    }
    public function doBar() {
        echo "Bar";
    }
}
$zip = new Zip();
$zip->doFoo();
$zip->doBar();

0
vbolshov at rbc dot ru ¶7 years ago

error_reporting(E_ALL | E_STRICT);
interface i {
        function f($arg);
}
class c implements i {
        function f($arg, $arg2 = null)
        {
        }
}

0
cyrille.berliat[no spam]free.fr ¶8 years ago

interface FooBar
{
    const SOME_CONSTANT = 'I am an interface constant';
    public function doStuff();
}

-1
spiritus.canis at gmail dot com ¶8 years ago

class AbstractClass {
   public function __ToString ( ) { return 'Here I am'; }
}
class DescendantClass extends AbstractClass {}
interface MyInterface {
   public function Hello ( AbstractClass $obj );
}
class MyClassOne implements MyInterface {
   public function Hello ( AbstractClass $obj ) {
       echo $obj;
   }
} // Will work as Interface Satisfied
$myDC = new DescendantClass() ;
MyClassOne::Hello( $myDC ) ;

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