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这篇文章给大家分享的是有关PHP面向对象程序设计之对象生成的示例分析的内容。小编觉得挺实用的,因此分享给大家做个参考,一起跟随小编过来看看吧。
具体如下:
对象
看个例子
<?php abstract class Employee { // 雇员 protected $name; function __construct( $name ) { $this->name = $name; } abstract function fire(); } class Minion extends Employee { // 奴隶 继承 雇员 function fire() { print "{$this->name}: I'll clear my desk\n"; } } class NastyBoss { // 坏老板 private $employees = array(); function addEmployee( $employeeName ) { // 添加员工 $this->employees[] = new Minion( $employeeName ); // 代码灵活性受到限制 } function projectFails() { if ( count( $this->employees ) > 0 ) { $emp = array_pop( $this->employees ); $emp->fire(); // 炒鱿鱼 } } } $boss = new NastyBoss(); $boss->addEmployee( "harry" ); $boss->addEmployee( "bob" ); $boss->addEmployee( "mary" ); $boss->projectFails(); // output: // mary: I'll clear my desk ?>
再看一个更具有灵活性的案例
<?php abstract 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 ) { // 传入对象 $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" ) ); // 直接以对象作为参数,更具有灵活性 $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 ?>
单例
<?php class Preferences { private $props = array(); private static $instance; // 私有的,静态属性 private function __construct() { } // 无法实例化,私有的构造函数 public static function getInstance() { // 返回对象 静态方法才可以被类访问,静态方法中要有静态属性 if ( empty( self::$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 ?>
点评:不能随意创建对象,只能通过Preferences::getInstance()来创建对象。
工厂模式
<?php 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"; } } class CommsManager { // 负责生产Bloggs对象 function getApptEncoder() { return new BloggsApptEncoder(); } } $obj = new CommsManager(); $bloggs = $obj->getApptEncoder(); // 获取对象 print $bloggs->encode(); ?>
output:
Appointment data encoded in BloggsCal format
进一步增加灵活性设置
<?php 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"; } } 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
工厂方法模式要把创建者类与要生产的产品类分离开来。
抽象工厂
通过抽象来来约束,成为一定的规矩。
<?php 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 { // 预约 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(); // 对象调用方法,返回对象,继续调用方法。 print $mgr->getFooterText(); ?>
output:
MegaCal header
Appointment data encoded in MegaCal format
MegaCal footer
更加牛逼的实现
<?php // 根据类图,规划类的代码。从大局入手。 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标记 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
改造成一个保存具体产品的工厂类。
<?php class 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 { // 地域工厂 private $sea; private $forest; private $plains; function __construct( Sea $sea, Plains $plains, Forest $forest ) { // 定义变量为类对象 $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 ( )
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