PHP面向?qū)ο蟪绦蛟O(shè)計(jì)組合模式與裝飾模式詳解
本文實(shí)例講述了PHP面向?qū)ο蟪绦蛟O(shè)計(jì)組合模式與裝飾模式。分享給大家供大家參考,具體如下:
組合模式
定義:組合模式定義了一個(gè)單根繼承體系,使具有截然不同職責(zé)的集合可以并肩工作。
一個(gè)軍隊(duì)的案例,
<?php abstract class Unit { // 個(gè)體 abstract function bombardStrength(); } class Archer extends Unit { // 弓箭手 function bombardStrength() { return 4; } } class LaserCannonUnit extends Unit { // 火炮手 function bombardStrength() { return 44; } } ?>
軍隊(duì)整合成員,輸出火力
<?php abstract class Unit { abstract function bombardStrength(); } class Archer extends Unit { function bombardStrength() { return 4; } } class LaserCannonUnit extends Unit { function bombardStrength() { return 44; } } class Army { // 軍隊(duì) private $units = array(); // 定義私有屬性 個(gè)體集 function addUnit( Unit $unit ) { // 添加成員 array_push( $this->units, $unit ); } function bombardStrength() { // 火力 $ret = 0; foreach( $this->units as $unit ) { $ret += $unit->bombardStrength(); } return $ret; } } $unit1 = new Archer(); $unit2 = new LaserCannonUnit(); $army = new Army(); $army->addUnit( $unit1 ); $army->addUnit( $unit2 ); print $army->bombardStrength(); // 輸出火力 ?>
output:
48
軍隊(duì)進(jìn)一步整合其他軍隊(duì)
<?php abstract class Unit { abstract function bombardStrength(); } class Archer extends Unit { function bombardStrength() { return 4; } } class LaserCannonUnit extends Unit { function bombardStrength() { return 44; } } class Army { private $units = array(); private $armies= array(); function addUnit( Unit $unit ) { array_push( $this->units, $unit ); } function addArmy( Army $army ) { array_push( $this->armies, $army ); } function bombardStrength() { $ret = 0; foreach( $this->units as $unit ) { $ret += $unit->bombardStrength(); } foreach( $this->armies as $army ) { $ret += $army->bombardStrength(); } return $ret; } } $unit1 = new Archer(); $unit2 = new LaserCannonUnit(); $army = new Army(); $army->addUnit( $unit1 ); $army->addUnit( $unit2 ); print $army->bombardStrength(); print "\n"; $army2 = clone $army; // 克隆軍隊(duì) $army->addArmy( $army2 ); print $army->bombardStrength(); print "\n"; ?>
output:
48
96
更好的方式,支持新增,移除等等其他功能。
<?php abstract class Unit { abstract function addUnit( Unit $unit ); abstract function removeUnit( Unit $unit ); abstract function bombardStrength(); } class Army extends Unit { // 軍隊(duì) private $units = array(); function addUnit( Unit $unit ) { if ( in_array( $unit, $this->units, true ) ) { // $this用于調(diào)用正常的屬性或方法,self調(diào)用靜態(tài)的方法,屬性或者常量 return; } $this->units[] = $unit; } function removeUnit( Unit $unit ) { // >= php 5.3 $this->units = array_udiff( $this->units, array( $unit ), function( $a, $b ) { return ($a === $b)?0:1; } ); // < php 5.3 // $this->units = array_udiff( $this->units, array( $unit ), // create_function( '$a,$b', 'return ($a === $b)?0:1;' ) ); // 對(duì)象數(shù)組,create_function,創(chuàng)建函數(shù) } function bombardStrength() { $ret = 0; foreach( $this->units as $unit ) { $ret += $unit->bombardStrength(); } return $ret; } } // quick example classes class Tank extends Unit { // 坦克 function addUnit( Unit $unit ) {} function removeUnit( Unit $unit ) {} function bombardStrength() { return 4; } } class Soldier extends Unit { // 士兵 function addUnit( Unit $unit ) {} function removeUnit( Unit $unit ) {} function bombardStrength() { return 8; } } $tank = new Tank(); $tank2 = new Tank(); $soldier = new Soldier(); $army = new Army(); $army->addUnit( $soldier ); $army->addUnit( $tank ); $army->addUnit( $tank2 ); print_r( $army ); print $army->bombardStrength()."\n"; $army->removeUnit( $soldier ); print_r( $army ); print $army->bombardStrength()."\n"; ?>
output:
Army Object ( [units:Army:private] => Array ( [0] => Soldier Object ( ) [1] => Tank Object ( ) [2] => Tank Object ( ) ) ) 16 Army Object ( [units:Army:private] => Array ( [1] => Tank Object ( ) [2] => Tank Object ( ) ) ) 8
添加異常處理
<?php abstract class Unit { abstract function addUnit( Unit $unit ); abstract function removeUnit( Unit $unit ); abstract function bombardStrength(); } class Army extends Unit { private $units = array(); function addUnit( Unit $unit ) { if ( in_array( $unit, $this->units, true ) ) { return; } $this->units[] = $unit; } function removeUnit( Unit $unit ) { // >= php 5.3 //$this->units = array_udiff( $this->units, array( $unit ), // function( $a, $b ) { return ($a === $b)?0:1; } ); // < php 5.3 $this->units = array_udiff( $this->units, array( $unit ), create_function( '$a,$b', 'return ($a === $b)?0:1;' ) ); } function bombardStrength() { $ret = 0; foreach( $this->units as $unit ) { $ret += $unit->bombardStrength(); } return $ret; } } class UnitException extends Exception {} class Archer extends Unit { function addUnit( Unit $unit ) { throw new UnitException( get_class($this)." is a leaf" ); } function removeUnit( Unit $unit ) { throw new UnitException( get_class($this)." is a leaf" ); } function bombardStrength() { return 4; } } $archer = new Archer(); $archer2 = new Archer(); $archer->addUnit( $archer2 ); ?>
output:
Fatal error: Uncaught exception 'UnitException' with message 'Archer is a leaf'
點(diǎn)評(píng):組合模式中的一切類都共享同一個(gè)父類型,可以輕松地在設(shè)計(jì)中添加新的組合對(duì)象或局部對(duì)象,而無需大范圍地修改代碼。
最終的效果,逐步優(yōu)化(完美):
<?php class UnitException extends Exception {} abstract class Unit { abstract function bombardStrength(); function addUnit( Unit $unit ) { throw new UnitException( get_class($this)." is a leaf" ); } function removeUnit( Unit $unit ) { throw new UnitException( get_class($this)." is a leaf" ); } } class Archer extends Unit { function bombardStrength() { return 4; } } class LaserCannonUnit extends Unit { function bombardStrength() { return 44; } } class Army extends Unit { private $units = array(); function addUnit( Unit $unit ) { if ( in_array( $unit, $this->units, true ) ) { return; } $this->units[] = $unit; } function removeUnit( Unit $unit ) { // >= php 5.3 //$this->units = array_udiff( $this->units, array( $unit ), // function( $a, $b ) { return ($a === $b)?0:1; } ); // < php 5.3 $this->units = array_udiff( $this->units, array( $unit ), create_function( '$a,$b', 'return ($a === $b)?0:1;' ) ); } function bombardStrength() { $ret = 0; foreach( $this->units as $unit ) { $ret += $unit->bombardStrength(); } return $ret; } } // create an army $main_army = new Army(); // add some units $main_army->addUnit( new Archer() ); $main_army->addUnit( new LaserCannonUnit() ); // create a new army $sub_army = new Army(); // add some units $sub_army->addUnit( new Archer() ); $sub_army->addUnit( new Archer() ); $sub_army->addUnit( new Archer() ); // add the second army to the first $main_army->addUnit( $sub_army ); // all the calculations handled behind the scenes print "attacking with strength: {$main_army->bombardStrength()}\n"; ?>
output:
attacking with strength: 60
更牛逼的組合處理,
<?php abstract class Unit { function getComposite() { return null; } abstract function bombardStrength(); } abstract class CompositeUnit extends Unit { // 抽象類繼承抽象類 private $units = array(); function getComposite() { return $this; } protected function units() { return $this->units; } function removeUnit( Unit $unit ) { // >= php 5.3 //$this->units = array_udiff( $this->units, array( $unit ), // function( $a, $b ) { return ($a === $b)?0:1; } ); // < php 5.3 $this->units = array_udiff( $this->units, array( $unit ), create_function( '$a,$b', 'return ($a === $b)?0:1;' ) ); } function addUnit( Unit $unit ) { if ( in_array( $unit, $this->units, true ) ) { return; } $this->units[] = $unit; } } class Army extends CompositeUnit { function bombardStrength() { $ret = 0; foreach( $this->units as $unit ) { $ret += $unit->bombardStrength(); } return $ret; } } class Archer extends Unit { function bombardStrength() { return 4; } } class LaserCannonUnit extends Unit { function bombardStrength() { return 44; } } class UnitScript { static function joinExisting( Unit $newUnit, Unit $occupyingUnit ) { // 靜態(tài)方法,直接通過類名來使用 $comp; if ( ! is_null( $comp = $occupyingUnit->getComposite() ) ) { // 軍隊(duì)合并處理 $comp->addUnit( $newUnit ); } else { // 士兵合并處理 $comp = new Army(); $comp->addUnit( $occupyingUnit ); $comp->addUnit( $newUnit ); } return $comp; } } $army1 = new Army(); $army1->addUnit( new Archer() ); $army1->addUnit( new Archer() ); $army2 = new Army(); $army2->addUnit( new Archer() ); $army2->addUnit( new Archer() ); $army2->addUnit( new LaserCannonUnit() ); $composite = UnitScript::joinExisting( $army2, $army1 ); print_r( $composite ); ?>
output:
Army Object ( [units:CompositeUnit:private] => Array ( [0] => Archer Object ( ) [1] => Archer Object ( ) [2] => Army Object ( [units:CompositeUnit:private] => Array ( [0] => Archer Object ( ) [1] => Archer Object ( ) [2] => LaserCannonUnit Object ( ) ) ) ) )
點(diǎn)評(píng):Unit 基礎(chǔ),CompositeUnit復(fù)合中實(shí)現(xiàn)add與remove。軍隊(duì)繼承Composite,射手繼承Archer。這樣射手中就不會(huì)有多余的add與remove方法了。
裝飾模式
裝飾模式幫助我們改變具體組件的功能。
看例子
<?php abstract class Tile { // 磚瓦 abstract function getWealthFactor(); // 獲取財(cái)富 } class Plains extends Tile { // 平原 private $wealthfactor = 2; function getWealthFactor() { return $this->wealthfactor; } } class DiamondPlains extends Plains { // 鉆石地段 function getWealthFactor() { return parent::getWealthFactor() + 2; } } class PollutedPlains extends Plains { // 污染地段 function getWealthFactor() { return parent::getWealthFactor() - 4; } } $tile = new PollutedPlains(); print $tile->getWealthFactor(); ?>
output:
-2
點(diǎn)評(píng):不具有靈活性,我們不能同時(shí)獲得鉆石與被污染的土地的資金情況。
裝飾模式使用組合和委托而不是只使用繼承來解決功能變化的問題。
看例子:
<?php abstract class Tile { abstract function getWealthFactor(); } class Plains extends Tile { private $wealthfactor = 2; function getWealthFactor() { return $this->wealthfactor; } } abstract class TileDecorator extends Tile { // 裝飾 protected $tile; function __construct( Tile $tile ) { $this->tile = $tile; } } class DiamondDecorator extends TileDecorator { // 鉆石裝飾 function getWealthFactor() { return $this->tile->getWealthFactor()+2; } } class PollutionDecorator extends TileDecorator { // 污染裝飾 function getWealthFactor() { return $this->tile->getWealthFactor()-4; } } $tile = new Plains(); print $tile->getWealthFactor(); // 2 $tile = new DiamondDecorator( new Plains() ); print $tile->getWealthFactor(); // 4 $tile = new PollutionDecorator( new DiamondDecorator( new Plains() )); print $tile->getWealthFactor(); // 0 ?>
output:
2
4
0
點(diǎn)評(píng):這個(gè)模型具有擴(kuò)展性。我們不需要?jiǎng)?chuàng)建DiamondPollutionPlains對(duì)象就可以構(gòu)建一個(gè)鉆石被污染的對(duì)象。
一個(gè)更逼真的例子
<?php class RequestHelper{} // 請(qǐng)求助手 abstract class ProcessRequest { // 進(jìn)程請(qǐng)求 abstract function process( RequestHelper $req ); } class MainProcess extends ProcessRequest { // 主進(jìn)程 function process( RequestHelper $req ) { print __CLASS__.": doing something useful with request\n"; } } abstract class DecorateProcess extends ProcessRequest { // 裝飾進(jìn)程 protected $processrequest; function __construct( ProcessRequest $pr ) { // 引用對(duì)象,委托 $this->processrequest = $pr; } } class LogRequest extends DecorateProcess { // 日志請(qǐng)求 function process( RequestHelper $req ) { print __CLASS__.": logging request\n"; // 當(dāng)前類,有點(diǎn)遞歸的感覺 $this->processrequest->process( $req ); } } class AuthenticateRequest extends DecorateProcess { // 認(rèn)證請(qǐng)求 function process( RequestHelper $req ) { print __CLASS__.": authenticating request\n"; $this->processrequest->process( $req ); } } class StructureRequest extends DecorateProcess { // 組織結(jié)構(gòu)請(qǐng)求 function process( RequestHelper $req ) { print __CLASS__.": structuring request\n"; $this->processrequest->process( $req ); } } $process = new AuthenticateRequest( new StructureRequest( new LogRequest ( new MainProcess() ))); // 這樣可以很靈活的組合進(jìn)程的關(guān)系,省去很多重復(fù)的繼承 $process->process( new RequestHelper() ); print_r($process); ?>
output:
AuthenticateRequest: authenticating request StructureRequest: structuring request LogRequest: logging request MainProcess: doing something useful with request AuthenticateRequest Object ( [processrequest:protected] => StructureRequest Object ( [processrequest:protected] => LogRequest Object ( [processrequest:protected] => MainProcess Object ( ) ) ) )
點(diǎn)評(píng):這里有一種遞歸的感覺,一層調(diào)用一層。模式是牛人總結(jié)出來用于靈活的解決一些現(xiàn)實(shí)問題的。牛!給開發(fā)多一點(diǎn)思路。
更多關(guān)于PHP相關(guān)內(nèi)容感興趣的讀者可查看本站專題:《php面向?qū)ο蟪绦蛟O(shè)計(jì)入門教程》、《PHP基本語法入門教程》、《PHP運(yùn)算與運(yùn)算符用法總結(jié)》、《PHP網(wǎng)絡(luò)編程技巧總結(jié)》、《PHP數(shù)組(Array)操作技巧大全》、《php字符串(string)用法總結(jié)》、《php+mysql數(shù)據(jù)庫操作入門教程》及《php常見數(shù)據(jù)庫操作技巧匯總》
希望本文所述對(duì)大家PHP程序設(shè)計(jì)有所幫助。
相關(guān)文章
在PHP中養(yǎng)成7個(gè)面向?qū)ο蟮暮昧?xí)慣
如果您尚未打算用 OO 原則創(chuàng)建應(yīng)用程序,則使用 PHP 的面向?qū)ο螅∣O)的語言特性,這 7 個(gè)習(xí)慣將幫助您開始在過程編程與 OO 編程之間進(jìn)行轉(zhuǎn)換。2010-07-07php實(shí)現(xiàn)指定字符串中查找子字符串的方法
這篇文章主要介紹了php實(shí)現(xiàn)指定字符串中查找子字符串的方法,涉及php中strpos()函數(shù)查找字符串的技巧,具有一定參考借鑒價(jià)值,需要的朋友可以參考下2015-03-03php實(shí)現(xiàn)XML和數(shù)組的相互轉(zhuǎn)化功能示例
這篇文章主要介紹了php實(shí)現(xiàn)XML和數(shù)組的相互轉(zhuǎn)化功能,結(jié)合實(shí)例形式分析了php實(shí)現(xiàn)xml轉(zhuǎn)數(shù)組及數(shù)組轉(zhuǎn)xml相關(guān)操作技巧,需要的朋友可以參考下2017-02-02PHP性能分析工具xhprof的安裝使用與注意事項(xiàng)
xhprof 是一款Facebook工程師開發(fā)和維護(hù)的一款PHP性能分析、調(diào)試工具,相較于xdebug要更輕量,更節(jié)省資源,強(qiáng)烈推薦大家使用。下面這篇文章主要給大家介紹了關(guān)于PHP性能分析工具xhprof的安裝與使用方法的相關(guān)資料,需要的朋友可以參考下。2017-12-12