如何使用Temple方法，泛型方法或其他方法优化代码？现在我必须编写三遍类似的代码

Question

Now I want to send the message to the people which may be student,teacher or schoolmaster,and all of them have the phone,name and availdSendMsgCount.Before send the message which means insert the data to database,I have to judge whether them can be sent or not.So I write the code like this:

if(sendType=SendType.student){
 List<Student> students=tStudentServiceImpl.queryByParam(conditionMap);
         sendPhoneCout=students.size(); 
         checkSendNumber(availdSendMsgCount,sendPhoneCout); 
Log log=logMsgSend(content,sendPhoneCout,sendType); 
         for (Student vo : students)      
 sendMsgItem(content,vo.getPhone(),vo.getName(),vo.getId(),log.getId()); 
}
 else if(sendType=SendType.teacher){
 List<Teacher> teachers=tTeacherServiceImpl.queryByParam(conditionMap);
         sendPhoneCout=teachers.size(); 
         checkSendNumber(availdSendMsgCount,sendPhoneCout); 
     Log log=logMsgSend(content,sendPhoneCout,sendType); 
         for (Teacher vo : teachers)      
   sendMsgItem(content,vo.getPhone(),vo.getName(),vo.getId(),log.getId()); 
}
else{
  List<Schoolmaster>  schoolmasters=tSchoolmasterServiceImpl.queryByParam(conditionMap);
         sendPhoneCout=schoolmasters.size(); 
         checkSendNumber(availdSendMsgCount,sendPhoneCout); 
     Log log=logMsgSend(content,sendPhoneCout,sendType); 
         for (Schoolmaster vo : schoolmasters)      
   sendMsgItem(content,vo.getMasterPhone(),vo.getMasterName(),vo.getId(),log.getId()); 
 }

I think this code is bad.But how to optimize?

Answer 1

When Schoolmaster, Teacher and Student implement the same interface or superclass then you could write one method with List as parameter which is doing all the stuff and that is called in each of your three cases.

On the other hand, why do you have three different classes? They seem to have exactly the same methods. Wouldn't one be enough with a type parameter that is deciding what kind of type it is?

Answer 2

I suggest you to create an interface and implement it in your dao classes, so each of them will behave differently.

public interface NameMe {
      void sendMsgItem(content, Integer logId); // it's not clear the type of content
}

There is the method

// replace T with type of 'conditionMap' object, it's not clear from your code
public static void getAndSendMessageItems(Function<T, List<NameMe>> serviceFunc,
        T conditionMap, Integer availdSendMsgCount, SendType sendType) { 
    List<NameMe> values = serviceFunc.apply(conditionMap);
    Integer sendPhoneCout = values.size(); 
    checkSendNumber(availdSendMsgCount, sendPhoneCout); 
    Log log = logMsgSend(content, sendPhoneCout, sendType); 
    for (NameMe i : values) {     
         i.sendMsgItem(content, log.getId());            
    }
}

And call it in your if/else

Function<T, List<NameMe>> serviceFunc = null; 
if (SendType.student.equals(sendType)) {
    serviceFunc = tStudentServiceImpl::queryByParam;
} else if (SendType.teacher.equals(sendType)) {
    serviceFunc = tTeacherServiceImpl::queryByParam;
} else {
    serviceFunc = tSchoolmasterServiceImpl::queryByParam;
}
getAndSendMessageItems(serviceFunc, conditionMap, availdSendMsgCount, sendType);

However, if your services implement the same interface, you even don't need to use Function<T, List<NameMe>> , you can just pass service via interface object.

Hope it helps!