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C语言的观察者模式
/*hdr ** Copyright ... ** AUTHOR MichaelMa ** DATE 4-May-2014 ** DESCRIPTION implement a mode of observer in C ** NOTE may be some bugs */ #include <stdio.h> #include <stdlib.h> #include <string.h> /***************************DEFINES************************************/ #define MAX_LIST_CNT 10 #define MAX_ID_LEN 256 /* zero members */ #define ZERO(TYPE,instance) struct TYPE instance; instance.TYPE##_constructor = TYPE##_constructor; instance.TYPE##_constructor(&instance); /***************************TYPEDEFS**********************************/ typedef struct _Observer* List; struct _Observer { char ID[MAX_ID_LEN]; void (*_Observer_constructor)(struct _Observer*); void (*_Observer_destructor)(struct _Observer*); void (*_Observer_Update)(struct _Observer*); }; struct _Fire { unsigned short m_nObserverCnt; List m_listObservers[MAX_LIST_CNT]; void (*_Fire_constructor)(struct _Fire*); void (*_Fire_destructor)(struct _Fire*); void (*_Fire_Notify)(struct _Fire*); void (*_Fire_AddObserver)(struct _Fire*,void* pElement); void (*_Fire_DelObserver)(struct _Fire*,void* pElement); }; /****************************FUNCTIONS**********************************/ void _Observer_Update(struct _Observer* pThis) { printf("%s\n",pThis->ID); } void _Observer_destructor(struct _Observer* pThis) { } void _Observer_constructor(struct _Observer* pThis) { memset(pThis->ID,0,sizeof(pThis->ID)); pThis->_Observer_Update = _Observer_Update; pThis->_Observer_destructor = _Observer_destructor; } void _Fire_Notify(struct _Fire* pThis) { unsigned short uIter = 0; pThis = pThis; for( ; uIter < pThis->m_nObserverCnt ; ++uIter) { (pThis->m_listObservers[uIter])->_Observer_Update(pThis->m_listObservers[uIter]); } } void _Fire_AddObserver(struct _Fire* pThis,void* pElement) { if(pThis->m_nObserverCnt < MAX_LIST_CNT) { pThis->m_listObservers[pThis->m_nObserverCnt] = (List)pElement; ++(pThis->m_nObserverCnt); } else { printf("list is full now!\n"); } } void _Fire_DelObserver(struct _Fire* pThis,void* pElement) { unsigned short uIter = 0; unsigned short uInnerIter = 0; for( ; uIter < pThis->m_nObserverCnt ; uIter++) { if(pThis->m_listObservers[uIter] == pElement) { --(pThis->m_nObserverCnt); for(uInnerIter = uIter; uInnerIter < (pThis->m_nObserverCnt - uIter) ; uInnerIter++) { pThis->m_listObservers[uInnerIter] = pThis->m_listObservers[uInnerIter + 1]; } pThis->m_listObservers[pThis->m_nObserverCnt] = NULL; break; } } } void _Fire_destructor(struct _Fire* pThis) { } void _Fire_constructor(struct _Fire* pThis) { pThis->m_nObserverCnt = 0; memset(pThis->m_listObservers,0,sizeof(pThis->m_listObservers)); pThis->_Fire_Notify = _Fire_Notify; pThis->_Fire_AddObserver = _Fire_AddObserver; pThis->_Fire_DelObserver = _Fire_DelObserver; pThis->_Fire_destructor = _Fire_destructor; } int main(void) { printf("init...\n"); ZERO(_Observer,obs1); strcpy(obs1.ID,"MichaelMa"); ZERO(_Observer,obs2); strcpy(obs2.ID,"ZhangZhan"); ZERO(_Observer,obs3); strcpy(obs3.ID,"ChenFeng"); ZERO(_Observer,obs4); strcpy(obs4.ID,"LuoJi"); ZERO(_Fire,fire); fire._Fire_AddObserver(&fire,&obs1); fire._Fire_AddObserver(&fire,&obs2); fire._Fire_AddObserver(&fire,&obs3); fire._Fire_AddObserver(&fire,&obs4); fire._Fire_Notify(&fire); printf("----------------------------\n"); fire._Fire_DelObserver(&fire,&obs1); fire._Fire_Notify(&fire); printf("----------------------------\n"); fire._Fire_AddObserver(&fire,&obs1); fire._Fire_Notify(&fire); printf("finished...!\n"); return 0; }
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