今天在看cocos2d的时候，看到Action的设计采用了组合模式和装饰模式,可以将一系列的action组合起来,让CCNodec对象执行,就像给CCNode下达一系列的命令一样.
例如以下代码：
1 CCActionInterval* move =CCMoveBy::actionWithDuration(0.5f, ccp(0,160)); 2 CCActionInterval*rotate = CCRotateBy::actionWithDuration(2, 360); 3 CCActionInterval*scale = CCScaleBy::actionWithDuration(2, 5); 4 CCActionInterval*opacity = CCFadeOut::actionWithDuration(2); 5 CCActionInterval*fadein = CCFadeIn::actionWithDuration(2); 6 CCActionInterval* scaleback =CCScaleTo::actionWithDuration(1, 1); 7 CCFiniteTimeAction*seq0 = CCSequence::actions(move, rotate, scale, opacity, fadein, scaleback,NULL); 8 Actor->runAction(seq0);
于是就看了一下组合模式,写了个小例子：
1 #include <vector> 2 //组合模式是为了让访问单一对象与多个对象具有一致性。 3 // 想一下我们就可以知道可以用循环去遍历对象数组。提供通用接口 4 abstract class Component 5 { 6 public: vector<Component> vect ; 7 virtual int add() = 0 ; 8 virtual int del(&Component) = 0 ; 9 virtual int run() = 0 ; 10 }; 11 class composite:public Component 12 { 13 public: composite(); 14 int add(&Component); 15 int del(&Component); 16 int run(); 17 ~composite(); 18 }; 19 20 composite::composite() { } 21 composite::add(Component &item) 22 { vect.push_back(item); } 23 composite::del(Component &item) 24 { 25 for( vector<Component*>::iterator it=vect.begin();it!=vect.end() ) 26 { 27 //erase()并不会删除*it指向的对象，所以我们需要额外释放它 28 //这里如何判断两个对象是否相等呢？我们可以判断它们的地址是否相等 29 it == item ? vect.erase(it) : it++ ; 30 } 31 //使用swap来减少容量 32 vector(vect).swap(vect); 33 } 34 composite::run() 35 { 36 vector<Component*>::iterator it ; 37 for( it= vect.begin();it!=vect.end();it++ ) 38 { *it->run() ; } 39 } 40 composite::~composite() {} 41 int main() 42 { 43 composite vect = new composite(); 44 //单个对象 45 Component single = new Component(); 46 vect.add(&single); 47 vect.run(); 48 Component mul1 = new Component(); 49 Component mul2 = new Component(); 50 Component mul3 = new Component(); 51 vect.add(&mul1); 52 vect.add(&mul2); 53 vect.add(&mul3); 54 vect.run(); 55 //向量内存放的只是对象的副本，所以析构时不会释放对象的内存，我们需要手动释放 56 delete single ; 57 delete mul1; 58 delete mul2; 59 delete mul3; 60 return 0; 61 }
平时用C++不多，看了大半天的STL，真感慨C++的内存管理如此复杂...