PHP面向对象程序设计组合模式与装饰模式详解

本文实例讲述了PHP面向对象程序设计组合模式与装饰模式。分享给大家供大家参考，具体如下：

组合模式

定义：组合模式定义了一个单根继承体系，使具有截然不同职责的集合可以并肩工作。

一个军队的案例，

军队整合成员，输出火力

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(); // 输出火力
?>

output:
48
军队进一步整合其他军队

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; // 克隆军队
$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。

units,true ) ) { // $this用于调用正常的属性或方法，self调用静态的方法，属性或者常量
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( $this->units,// create_function( '$a,$b','return ($a === $b)?0:1;' ) );
// 对象数组，create_function,创建函数
}
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:

Array
(
[0] => Soldier Object
(
)
[1] => Tank Object
(
)
[2] => Tank Object
(
)
)
)
16
Army Object
(
[units:Army:private] => Array
(
[1] => Tank Object
(
)
[2] => Tank Object
(
)
)
)
8

添加异常处理

units[] = $unit;
}
function removeUnit( Unit $unit ) {
// >= php 5.3
//$this->units = array_udiff( $this->units,// function( $a,$b ) { return ($a === $b)?0:1; } );
// < php 5.3 $this->units = array_udiff( $this->units,create_function( '$a,'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'

点评：组合模式中的一切类都共享同一个父类型，可以轻松地在设计中添加新的组合对象或局部对象，而无需大范围地修改代码。

最终的效果，逐步优化(完美)：