IPC Spring 2013IPC Spring 2013

Decoupling Objects WithStandard Interfaces

About MeAbout Me● Thomas Weinert

● papaya Software GmbH● papaya CMS

● Twitter: @ThomasWeinert● Web: http://www.a-basketful-of-papayas.net

InterfacesInterfaces● By Declaration● By Convention

● Magic Methods

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

ImplementImplement

class Foo implements Countable, IteratorAggregate { }

ExtendExtend

interface Foo extends IteratorAggregate { }

ValidateValidate

if ($foo instanceOf Traversable) { }

Type HintsType Hints

function bar(Traversable $foo) { }

InterfacesInterfaces

By Convention

Object InitializationObject Initialization● Magic Methods

● __construct()● __destruct()● __clone()● __sleep()/__wakeup() → Serializeable● __set_state()

__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);}

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

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

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

__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 ) );}

__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 ...

__call/__callStatic__call/__callStatic

Dynamic Methods/Functions

Generic CallbacksGeneric Callbacksclass 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

PHP DocumentorPHP Documentor/* * … * * @property Callable $onExample * @method mixed onExample() */class MyEvents extends Events {

public function __construct() { parent::__construct(['example' => 21]); }}

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

__invoke__invoke● Functors

● Callable

Callback ListsCallback Lists...$queries = Io\Deferred::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); } ));

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); }}

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

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

Predeclared Interfaces

SerializeableSerializeable● Usage

● serialize($object)● unserialize($string);

● Methods● $object->serialize()● $object->unserialize($string);

JsonSerializableJsonSerializable● Usage

● json_encode()

● Method● $object->jsonSerialize()

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

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

OffsetExists()OffsetExists()

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

OffsetGet()OffsetGet()

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

OffsetSet()OffsetSet()

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

OffsetUnset()OffsetUnset()

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

Array DereferencingArray Dereferencing

echo $object->foo()[0];

CountableCountable● count($foo)

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

TraversableTraversable● foreach● Iterator● IteratorAggregate

Iterator InterfacesIterator Interfaces

Traversable

Iterator

OuterIterator

IteratorAggregate

RecursiveIteratorSeekableIterator

SPL

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

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

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); }}

Predefined IteratorsPredefined Iterators● ArrayIterator● EmptyIterator● RegexIterator● …

Nest IteratorsNest Iterators● IteratorIterator

● AppendIterator● CallbackFilterIterator● ...

RecursiveIteratorRecursiveIterator● List with Children

$items = [ 1 => '1', 2 => '1.1', 3 => '2'];

$structure = [ 0 => [1, 3], 1 => [2]];

Inherit from IteratorIteratorInherit from IteratorIteratorclass 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; }...

hasChildren()hasChildren()

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

getChildren()getChildren()

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

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";}

ResultResult* 1

** 1.1

* 2

● No recursive function call● Works with Traversable/ArrayAccess● Allows for Lazy Initalization

ObserverObserver

Subject

Observer 2 Observer 2Observer 2

ObserverObserver

CMS Page published

Log Action Announce ToWebservice

Invalidate Cache

ObserverObserver● SplObserver

● update()

● SplSubject● attach()● detach()● notify()

Thank YouThank You

● Twitter: @ThomasWeinert

● https://joind.in/8807