PHP面向对象程序设计之对象生成方法详解

<?phpabstract 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?>

<?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 ) { // 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?>

<?phpclass 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?>

<?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 { // 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();?>

<?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";?>

<?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 { // 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();?>

<?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();?>

<?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() );?>

EarthSea Object()EarthPlains Object()EarthForest Object()