本文實例講述了PHP面向對象程序設計之對象生成方法。分享給大家供大家參考,具體如下:
對象
看個例子
<?phpabstract class Employee { // 雇員 protected $name; function __construct( $name ) { $this->name = $name; } abstract function fire();}class Minion extends Employee { // 奴隸 繼承 雇員 function fire() { print "{$this->name}: I'll clear my desk/n"; }}class NastyBoss { // 壞老板 private $employees = array(); function addEmployee( $employeeName ) { // 添加員工 $this->employees[] = new Minion( $employeeName ); // 代碼靈活性受到限制 } function projectFails() { if ( count( $this->employees ) > 0 ) { $emp = array_pop( $this->employees ); $emp->fire(); // 炒魷魚 } }}$boss = new NastyBoss();$boss->addEmployee( "harry" );$boss->addEmployee( "bob" );$boss->addEmployee( "mary" );$boss->projectFails();// output:// mary: I'll clear my desk?>再看一個更具有靈活性的案例
<?phpabstract class Employee { protected $name; function __construct( $name ) { $this->name = $name; } abstract function fire();}class Minion extends Employee { function fire() { print "{$this->name}: I'll clear my desk/n"; }}class NastyBoss { private $employees = array(); function addEmployee( Employee $employee ) { // 傳入對象 $this->employees[] = $employee; } function projectFails() { if ( count( $this->employees ) ) { $emp = array_pop( $this->employees ); $emp->fire(); } }}// new Employee class...class CluedUp extends Employee { function fire() { print "{$this->name}: I'll call my lawyer/n"; }}$boss = new NastyBoss();$boss->addEmployee( new Minion( "harry" ) ); // 直接以對象作為參數,更具有靈活性$boss->addEmployee( new CluedUp( "bob" ) );$boss->addEmployee( new Minion( "mary" ) );$boss->projectFails();$boss->projectFails();$boss->projectFails();// output:// mary: I'll clear my desk// bob: I'll call my lawyer// harry: I'll clear my desk?>單例
<?phpclass Preferences { private $props = array(); private static $instance; // 私有的,靜態屬性 private function __construct() { } // 無法實例化,私有的構造函數 public static function getInstance() { // 返回對象 靜態方法才可以被類訪問,靜態方法中要有靜態屬性 if ( empty( self::$instance ) ) { self::$instance = new Preferences(); } return self::$instance; } public function setProperty( $key, $val ) { $this->props[$key] = $val; } public function getProperty( $key ) { return $this->props[$key]; }}$pref = Preferences::getInstance();$pref->setProperty( "name", "matt" );unset( $pref ); // remove the reference$pref2 = Preferences::getInstance();print $pref2->getProperty( "name" ) ."/n"; // demonstrate value is not lost?>點評:不能隨意創建對象,只能通過Preferences::getInstance()來創建對象。
工廠模式
<?phpabstract class ApptEncoder { abstract function encode();}class BloggsApptEncoder extends ApptEncoder { function encode() { return "Appointment data encoded in BloggsCal format/n"; }}class MegaApptEncoder extends ApptEncoder { function encode() { return "Appointment data encoded in MegaCal format/n"; }}class CommsManager { // 負責生產Bloggs對象 function getApptEncoder() { return new BloggsApptEncoder(); }}$obj = new CommsManager();$bloggs = $obj->getApptEncoder(); // 獲取對象print $bloggs->encode();?>
output:
Appointment data encoded in BloggsCal format
進一步增加靈活性設置
<?phpabstract class ApptEncoder { abstract function encode();}class BloggsApptEncoder extends ApptEncoder { function encode() { return "Appointment data encoded in BloggsCal format/n"; }}class MegaApptEncoder extends ApptEncoder { function encode() { return "Appointment data encoded in MegaCal format/n"; }}class CommsManager { const BLOGGS = 1; const MEGA = 2; private $mode ; function __construct( $mode ) { $this->mode = $mode; } function getHeaderText() { switch ( $this->mode ) { case ( self::MEGA ): return "MegaCal header/n"; default: return "BloggsCal header/n"; } } function getApptEncoder() { switch ( $this->mode ) { case ( self::MEGA ): return new MegaApptEncoder(); default: return new BloggsApptEncoder(); } }}$man = new CommsManager( CommsManager::MEGA );print ( get_class( $man->getApptEncoder() ) )."/n";$man = new CommsManager( CommsManager::BLOGGS );print ( get_class( $man->getApptEncoder() ) )."/n";?>output:
MegaApptEncoder
BloggsApptEncoder
工廠方法模式要把創建者類與要生產的產品類分離開來。
抽象工廠
通過抽象來來約束,成為一定的規矩。
<?phpabstract class ApptEncoder { abstract function encode();}class BloggsApptEncoder extends ApptEncoder { function encode() { return "Appointment data encoded in BloggsCal format/n"; }}class MegaApptEncoder extends ApptEncoder { function encode() { return "Appointment data encoded in MegaCal format/n"; }}abstract class CommsManager { // 預約 abstract function getHeaderText(); abstract function getApptEncoder(); abstract function getTtdEncoder(); abstract function getContactEncoder(); abstract function getFooterText();}class BloggsCommsManager extends CommsManager { function getHeaderText() { return "BloggsCal header/n"; } function getApptEncoder() { return new BloggsApptEncoder(); } function getTtdEncoder() { return new BloggsTtdEncoder(); } function getContactEncoder() { return new BloggsContactEncoder(); } function getFooterText() { return "BloggsCal footer/n"; }}class MegaCommsManager extends CommsManager { function getHeaderText() { return "MegaCal header/n"; } function getApptEncoder() { return new MegaApptEncoder(); } function getTtdEncoder() { return new MegaTtdEncoder(); } function getContactEncoder() { return new MegaContactEncoder(); } function getFooterText() { return "MegaCal footer/n"; }}$mgr = new MegaCommsManager();print $mgr->getHeaderText();print $mgr->getApptEncoder()->encode(); // 對象調用方法,返回對象,繼續調用方法。print $mgr->getFooterText();?>output:
MegaCal header
Appointment data encoded in MegaCal format
MegaCal footer
更加牛逼的實現
<?php// 根據類圖,規劃類的代碼。從大局入手。abstract class ApptEncoder { abstract function encode();}class BloggsApptEncoder extends ApptEncoder { function encode() { return "Appointment data encoded in BloggsCal format/n"; }}class MegaApptEncoder extends ApptEncoder { function encode() { return "Appointment data encoded in MegaCal format/n"; }}abstract class CommsManager { const APPT = 1; const TTD = 2; const CONTACT = 3; abstract function getHeaderText(); abstract function make( $flag_int ); // int標記 abstract function getFooterText();}class BloggsCommsManager extends CommsManager { function getHeaderText() { return "BloggsCal header/n"; } function make( $flag_int ) { switch ( $flag_int ) { case self::APPT: // self直接控制常量 return new BloggsApptEncoder(); case self::CONTACT: return new BloggsContactEncoder(); case self::TTD: return new BloggsTtdEncoder(); } } function getFooterText() { return "BloggsCal footer/n"; }}$mgr = new BloggsCommsManager();print $mgr->getHeaderText();print $mgr->make( CommsManager::APPT )->encode();print $mgr->getFooterText();?>output:
BloggsCal header
Appointment data encoded in BloggsCal format
BloggsCal footer
原型模式
改造成一個保存具體產品的工廠類。
<?phpclass Sea {} // 大海class EarthSea extends Sea {}class MarsSea extends Sea {}class Plains {} // 平原class EarthPlains extends Plains {}class MarsPlains extends Plains {}class Forest {} // 森林class EarthForest extends Forest {}class MarsForest extends Forest {}class TerrainFactory { // 地域工廠 private $sea; private $forest; private $plains; function __construct( Sea $sea, Plains $plains, Forest $forest ) { // 定義變量為類對象 $this->sea = $sea; $this->plains = $plains; $this->forest = $forest; } function getSea( ) { return clone $this->sea; // 克隆 } function getPlains( ) { return clone $this->plains; } function getForest( ) { return clone $this->forest; }}$factory = new TerrainFactory( new EarthSea(), new EarthPlains(), new EarthForest() );print_r( $factory->getSea() );print_r( $factory->getPlains() );print_r( $factory->getForest() );?>output:
EarthSea Object()EarthPlains Object()EarthForest Object()
希望本文所述對大家PHP程序設計有所幫助。
新聞熱點
疑難解答
圖片精選