1.
IPC Spring 2013IPC Spring 2013
Decoupling Objects With
Standard Interfaces

2.
About MeAbout Me
● Thomas Weinert
● papaya Software GmbH
● papaya CMS
● Twitter: @ThomasWeinert
● Web: http://www.a-basketful-of-papayas.net

3.
InterfacesInterfaces
● By Declaration
● By Convention
● Magic Methods

4.
ReasonsReasons
● Encapsulation
● Reuse
● S.O.L.I.D.

5.
ImplementImplement
class Foo
implements
Countable,
IteratorAggregate {
}

6.
ExtendExtend
interface Foo extends IteratorAggregate {
}

7.
ValidateValidate
if ($foo instanceOf Traversable) {
}

8.
Type HintsType Hints
function bar(Traversable $foo) {
}

9.
InterfacesInterfaces
By Convention

10.
Object InitializationObject Initialization
● Magic Methods
● __construct()
● __destruct()
● __clone()
● __sleep()/__wakeup() → Serializeable
● __set_state()

11.
__toString__toString
● Cast an object to string
/**
* Casting the object to string will
*return the last value
* @return string
*/
public function __toString() {
return (string)end($this->_values);
}

12.
Dynamic PropertiesDynamic Properties
● $object->value = 123
● $value = $object->value;
● $object->setValue(123);
● $value = $object->getValue();

13.
Dynamic PropertiesDynamic Properties
● __isset()
● __get()
● __set()
● __unset()

14.
__isset()__isset()
/**
* @param string $name
* @return boolean
*/
public function __isset($name) {
switch ($name) {
case 'name' :
case 'value' :
case 'values' :
return TRUE;
}
return FALSE;
}

15.
__get()__get()
/**
* @param string $name
* @throws InvalidArgumentException
* @return mixed
*/
public function __get($name) {
switch ($name) {
case 'name' :
return $this->_name;
case 'value' :
return end($this->_values);
case 'values' :
return $this->_values;
}
throw new LogicException(
sprintf(
'Can not read non existing property: %s::$%s',
__CLASS__,
$name
)
);
}

16.
__set()__set()
/**
* @param string $name
* @param string|array|Traversable $value
* @throws LogicException
*/
public function __set($name, $value) {
switch ($name) {
case 'name' :
$this->setName($value);
return;
case 'value' :
$this->setData((string)$value);
return;
case 'values' :
$this->setData($value);
return;
}
throw new LogicException(
sprintf('Can not write non existing property: %s::$%s',
__CLASS__, $name
...

17.
__call/__callStatic__call/__callStatic
Dynamic Methods/Functions

18.
Generic CallbacksGeneric Callbacks
class MyEvents extends Events {
public function __construct() {
parent::__construct(['example' => 21]);
}
}
$my = new MyEvents();
echo $my->onExample(), "n"; //21
$my->onExample = function () {
return 42;
};
echo $my->onExample(), "n"; //42
$my->onExample = 23;
echo $my->onExample(), "n"; //23

19.
PHP DocumentorPHP Documentor
/*
* …
*
* @property Callable $onExample
* @method mixed onExample()
*/
class MyEvents extends Events {
public function __construct() {
parent::__construct(['example' => 21]);
}
}

20.
CallableCallable
● 'function'
● array($object, 'method')
● function() {}
● class {}

21.
__invoke__invoke
● Functors
● Callable

22.
Callback ListsCallback Lists
...
$queries = IoDeferred::When(
$mysqlOne("SELECT 'Query 1', SLEEP(5)")
->done(
function($result) use ($time) {
var_dump(iterator_to_array($result));
var_dump(microtime(TRUE) - $time);
}
),
$mysqlTwo("SELECT 'Query 2', SLEEP(1)")
->done(
function($result) use ($time) {
var_dump(iterator_to_array($result));
var_dump(microtime(TRUE) - $time);
}
)
);

23.
Functor ExampleFunctor Example
class DatabaseResultDebugger {
private $_startTime = 0;
public function __construct($startTime) {
$this->_startTime = $startTime;
}
public function __invoke($result) {
var_dump(iterator_to_array($result));
var_dump(microtime(TRUE) - $this->_startTime);
}
}

24.
Callback HandlersCallback Handlers
$queries = IoDeferred::When(
$mysqlOne("SELECT 'Query 1', SLEEP(5)")
->done(
new DatabaseResultDebugger($time)
),
$mysqlTwo("SELECT 'Query 2', SLEEP(1)")
->done(
new DatabaseResultDebugger($time)
)
);

25.
More Callback HandlersMore Callback Handlers
$queries = IoDeferred::When(
$mysqlOne("SELECT 'Query 1', SLEEP(5)")
->done(
new ConcreteDatabaseResultHandler()
)
->done(
new DatabaseResultDebugger($time)
),
$mysqlTwo("SELECT 'Query 2', SLEEP(1)")
->done(
new DatabaseResultDebugger($time)
)
);

26.
Predeclared Interfaces

27.
SerializeableSerializeable
● Usage
● serialize($object)
● unserialize($string);
● Methods
● $object->serialize()
● $object->unserialize($string);

28.
JsonSerializableJsonSerializable
● Usage
● json_encode()
● Method
● $object->jsonSerialize()

29.
ArrayAccessArrayAccess
● [] -Syntax
● Validation
● Conversion
● Lazy Initialization

30.
ArrayAccess MethodsArrayAccess Methods
● offsetExists()
● offsetGet()
● offsetSet()
● offsetUnset()

31.
OffsetExists()OffsetExists()
/**
* @param integer $offset
* @return boolean
*/
public function offsetExists($offset) {
return array_key_exists($offset, $this->_values);
}

32.
OffsetGet()OffsetGet()
/**
* @param integer $offset
*/
public function offsetGet($offset) {
return $this->_values[$offset];
}

33.
OffsetSet()OffsetSet()
/**
* @param integer $offset
* @param string $value
*/
public function offsetSet($offset, $value) {
if (NULL === $offset) {
$this->_values[] = $value;
} else {
$this->_values[$offset] = $value;
}
}

34.
OffsetUnset()OffsetUnset()
/**
* @param integer $offset
*/
public function offsetUnset($offset) {
unset($this->_values[$offset]);
}

35.
Array DereferencingArray Dereferencing
echo $object->foo()[0];

36.
CountableCountable
● count($foo)
class DatabaseResult implements Countable {
...
public function count() {
return $this->_count;
}
...
}

37.
TraversableTraversable
● foreach
● Iterator
● IteratorAggregate

38.
Iterator InterfacesIterator Interfaces
Traversable
Iterator
OuterIterator
IteratorAggregate
RecursiveIteratorSeekableIterator
SPL

39.
Iterator functionsIterator functions
● foreach()
● iterator_to_array()
● iterator_count()
● iterator_apply()

40.
IteratorIterator
● rewind()
● next()
● valid()
● current()
● key()

41.
IteratorAggregateIteratorAggregate
● getIterator()
class Foo implements IteratorAggregate {
private $_items = array();
public function __construct(array $items) {
$this->_items = $items;
}
public function getIterator() {
return new ArrayIterator($this->_items);
}
}

42.
Predefined IteratorsPredefined Iterators
● ArrayIterator
● EmptyIterator
● RegexIterator
● …

43.
Nest IteratorsNest Iterators
● IteratorIterator
● AppendIterator
● CallbackFilterIterator
● ...

44.
RecursiveIteratorRecursiveIterator
● List with Children
$items = [
1 => '1',
2 => '1.1',
3 => '2'
];
$structure = [
0 => [1, 3],
1 => [2]
];

45.
Inherit from IteratorIteratorInherit from IteratorIterator
class Bar
extends IteratorIterator
implements RecursiveIterator {
private $_items = [];
private $_structure = [];
public function __construct($items, $structure, $parent = 0) {
$siblings = [];
if (!empty($structure[$parent])) {
foreach ($structure[$parent] as $id) {
if (isset($items[$id])) {
$siblings[$id] = $items[$id];
}
}
}
parent::__construct(new ArrayIterator($siblings));
$this->_items = $items;
$this->_structure = $structure;
}
...

46.
hasChildren()hasChildren()
public function hasChildren() {
return
$this->valid() &&
isset($this->_structure[$this->key()]);
}

47.
getChildren()getChildren()
public function getChildren() {
if ($this->hasChildren()) {
return new $this(
$this->_items,
$this->_structure,
$this->key()
);
} else {
return new $this([], []);
}
}

48.
RecursiveIteratorIteratorRecursiveIteratorIterator
● Iterator for RecursiveIterator
$iterator = new RecursiveIteratorIterator(
new Bar($items, $structure),
RecursiveIteratorIterator::SELF_FIRST
);
foreach ($iterator as $element) {
echo str_repeat('*', $iterator->getDepth() + 1);
echo $element;
echo "n";
}

49.
ResultResult
* 1
** 1.1
* 2
● No recursive function call
● Works with Traversable/ArrayAccess
● Allows for Lazy Initalization

50.
ObserverObserver
Subject
Observer 2 Observer 2Observer 2

51.
ObserverObserver
CMS Page published
Log Action Announce To
Webservice
Invalidate
Cache

52.
ObserverObserver
● SplObserver
● update()
● SplSubject
● attach()
● detach()
● notify()

53.
Thank YouThank You
● Twitter: @ThomasWeinert
● https://joind.in/8807