1. Dependency
Adding
Injection To Legacy
Applications

3. Who Is i3logix?

4. Inversion of Control

5. Dependency Injection

8. Built-In
Flexibility

9. interface Calc {
public function __invoke($left, $right);
}
class AddCalc implements Calc {
public function __invoke($left, $right) {
return $left + $right;
}
}
class SubCalc implements Calc {
public function __invoke($left, $right) {
return $left - $right;
}
}

10. class Calculator{
public function __invoke(Calc $calc, $left, $right){
return $calc($left, $right);
}
}
$calculator = new Calculator();
echo $calculator(new AddCalc(), 2, 1), "n";
echo $calculator(new SubCalc(), 2, 1), "n";

11. De-Coupling

12. Have Clear Goals

14. It’s
only
a
Tool

15. I T
N E
J C
H
E
N
C
I
T
Q
I
U
O
E
N S

17. class Status {
public function get($system) {
$client = new Zend_Http_Client();
$r = $client->setUri(SERVICE_URI)
->setParameterGet(compact('system'))
->request('GET');
if ($r->isSuccessful()) {
return $r->getBody();
}
return false;
}
}

18. Constructor
Injection
Vs.
Setter/Property
Injection

19. class StatusSetterInject{
protected $client;
public function setClient(Zend_Http_Client $client){
$this->client = $client;
}
public function get($system){
$r = $this->client->setUri(SERVICE_URI)
->setParameterGet(compact('system'))
->request('GET');
if ($r->isSuccessful()){
return $r->getBody();
}
return false;
}
}

20. class StatusConstructInject{
protected $client;
public function __construct(Zend_Http_Client $client){
$this->client = $client;
}
public function get($system){
$r = $this->client->setUri(SERVICE_URI)
->setParameterGet(compact('system'))
->request('GET');
if($r->isSuccessful()){
return $r->getBody();
}
return false;
}
}

21. Init Pattern

22. class StatusInit{
protected $client;
public function __construct(Zend_Http_Client $client){
$this->client = $client;
$this->init();
}
public function init(){
//Left empty
}
public function get($system){
$r = $this->client->setUri(SERVICE_URI)
->setParameterGet(compact('system'))
->request('GET');
//...
}
}

23. Optional
Injection

24. class StatusConstructInjectOptional{
protected $client;
public function __construct(
Zend_Http_Client $client = null){
if($client === null){
$client = new Zend_Http_Client();
}
$this->client = $client;
}
public function get($system){
$r = $this->client->setUri(SERVICE_URI)
->setParameterGet(compact('system'))
->request('GET');
//...
}
}

25. class StatusSetterInjectOptional{
protected $client;
public function setClient(Zend_Http_Client $client){
$this->client = $client;
}
protected function getClient(){
if ($this->client === null){
$this->client = new Zend_Http_Client();
}
return $this->client;
}
public function get($system){
$r = $this->getClient()->setUri(SERVICE_URI)
->setParameterGet(compact('system'))
->request('GET');
//...

26. Class Name Override

27. class StatusClassNameOverrideConstruct{
protected $clientClass;
public function __construct($class = 'Zend_Http_Client'){
$this->clientClass = $class;
}
public function get($system){
$client = new $this->clientClass;
$r = $this->getClient()->setUri(SERVICE_URI)
->setParameterGet(compact('system'))
->request('GET');
if($r->isSuccessful()){
return $r->getBody();
}
return false;
}
}

28. class StatusClassNameOverrideSetter{
protected $clientClass = 'Zend_Http_Client';
public function setClass($class){
$this->clientClass = $class;
}
public function get($system){
$client = new $this->clientClass;
$r = $this->getClient()->setUri(SERVICE_URI)
->setParameterGet(compact('system'))
->request('GET');
if($r->isSuccessful()){
return $r->getBody();
}
return false;
}
}

29. BUT I NEED TO CREATE OBJECTS?

30. class PolyBad {
public function foo($bar) {
if (get_class($bar) === 'SomeOtherClass') {
$tmp = new SomeClass();
}
}
}

31. class PolyGood {
public function foo(SomeClass $bar) {
if ($baz instanceof SomeInterface) {
// Do something
}
}
}

33. class Factory{
public function create(){
return new SimpleClass();
}
}

34. Dynamic Factory

35. abstract class FactoryAbstract{
protected abstract function getClassName();
public function create(){
$class = $this->getClassName();
$argList = func_get_args();
if (count($argList) < 1){
return new $class;
}
$rClass = new ReflectionClass($class);
return $rClass->newInstanceArgs($argList);
}
}

36. function __autoload($class){
$classPath = str_replace('_', '/', $class);
$filePath = __DIR__."/src/$classPath.php";
if (file_exists($filePath))
return require $filePath;
if (substr($class, -7) !== 'Factory')
return;
$subName = substr($class, 0, -8);
eval("class $class extends FactoryAbstract{
protected function getClassName(){
return '$subName';
}
}");
}

37. WHAT IS INJECTING THESE OBJECTS?

38. Injector, Provider, Container

39. Configuration

40. <service id="bar" class="FooClass" shared="true"
constructor="getInstance">
<file>%path%/foo.php</file>
<argument>foo</argument>
<argument type="service" id="foo" />
<argument type="collection">
<argument>true</argument>
<argument>false</argument>
</argument>
<configurator function="configure" />
<call method="setBar" />
<call method="setBar">
<argument>foo</argument>
<argument type="service" id="foo" />
<argument type="collection">
<argument>true</argument>
<argument>false</argument>
</argument>
</call>
</service>

41. Interfaces

42. if($obj instanceof InjectDb){
$obj->setDb($this->serviceLocator->getDb());
}
if($obj instanceof InjectTool){
$obj->setTool($this->serviceLocator->getTool());
}
if($obj instanceof InjectClientBuilder){
$obj->setClientBuilder($this->getClientBuilder());
}
if($obj instanceof InjectEvent){
$obj->setEvent($this->serviceLocator->getEvent());
}

43. Duck Typing

44. abstract class Zend_View_Abstract
implements Zend_View_Interface
//...
public function registerHelper($helper, $name){
//...
if (!$helper instanceof Zend_View_Interface){
if (!method_exists($helper, $name)){
require_once 'Zend/View/Exception.php';
$e = new Zend_View_Exception(
'View helper must …');
$e->setView($this);
throw $e;
}
}
if (method_exists($helper, 'setView')){
$helper->setView($this);
}
//...

45. Auto Wiring

46. $rParmList = $methodReflection->getParameters();
foreach($rParmList as $rParm ){
$parmClass = $rParm->getClass();
if($parmClass !== null){
$bindConfig->getInjectionConfig()
->addMethodInstanceKey(
$methodName, $parmClass->getName());
}else{
throw new Exception(
"Not possible to configure automatically"
);
}
}

47. Annotations

48. /**
* @Singleton
*/
class LoggerSimple{
/**
* @Inject Zend_Db_Adapter_Abstract
*/
public $db;
/**
* @Inject
* @Arg Zend_Db_Adapter_Abstract
*/
public function __construct($db){
$this->db = $db;
}
/**
* @Inject
* @Arg Zend_Db_Adapter_Abstract
*/
public function setDb($db){
$this->db = $db;
}
}

49. /**
* @ImplementedBy LoggerSimple
*/
interface Logger{
public function log($message, $level);
}

50. $rClass = new ReflectionAnnotatedClass($config->getClass());
if($rClass->isInterface()){
if($rClass->hasAnnotation('ImplementedBy') === false){
throw new Exception(…);
}
$impClass = $rClass->getAnnotation('ImplementedBy')->value;
if($impClass === null){
throw new Exception (…);
}
$config->setImplementationClass($impClass);
}

51. Combine. Win!

53. Singleton

54. class Db{
protected function __construct(){}
protected function __clone(){}
public static function instance(){
static $instance = null;
if($instance === null){
$instance = new static();
}
return $instance;
}
}

55. Singleton + Registry

56. class Registry{
protected static $reg = array();
public static function add($key, $value){
static::$reg[$key] = $value;
}
public static function get($key){
return static::$reg[$key];
}
}

57. class Registry{
protected static $reg = array();
public static function add($key, $value){
static::$reg[$key] = $value;
}
public static function get($key){
$value = static::$reg[$key];
if(is_callable($value)){
return $value();
}
return $value;
}
}

58. Registry::add('db', function (){return new Db();});
var_dump(Registry::get('db'));

59. Service Locator

60. class ServiceLocator{
protected function __construct(){}
protected function __clone(){}
public static function instance(){
static $instance = null;
if($instance === null){
$instance = new static();
}
return $instance;
}
public function getDb(){
static $db = null;
if($db === null){
$db = new Db();
}
return $db;
}
}

61. Coarse-Grained
Fine-Grained

63. Design by
Contract

64. class Logger{}

65. abstract class LoggerAbstract{}
class LoggerEcho extends LoggerAbstract{}
class LoggerFile extends LoggerAbstract{}

66. interface LoggerInterface{}
abstract class LoggerAbstract implements LoggerInterface{}
class LoggerEcho extends LoggerAbstract{}
class LoggerFile extends LoggerAbstract{}
class LoggerOddBall implements LoggerInterface{}

67. class Logger{}

68. abstract class Logger{}
class LoggerEcho extends Logger{}
class LoggerFile extends Logger{}

69. interface Logger{}
abstract class LoggerAbstract implements Logger{}
class LoggerEcho extends Logger{}
class LoggerFile extends Logger{}
class LoggerOddBall implements Logger{}

70. Prefer Composition Over Inheritance

71. WHAT’S ALREADY OUT THERE?

75. YOU NEED
A
GAME PLAN!

77. http://joind.in/3740
T HANK Y OU!